Typhoid

Efficacy of typhoid conjugate vaccine: final analysis of a 4-year, phase 3, randomised controlled trial in Malawian children

The World Health Organization (WHO) says an estimated 9 million people get sick from typhoid, and 110,000 people die from Salmonella Typhi, commonly known as typhoid.

In 2024, millions of children who lack access to safe drinking water and adequate sanitation are at risk in typhoid-endemic countries, particularly in Asia and sub-Saharan Africa.

Furthermore, travelers to these countries are usually at risk when exposed to low food hygiene standards and poor water quality, says the WHO.

The good news is that approved typhoid vaccines are available in 2024.

But, the duration of effectiveness has been debated for years.

A peer-reviewed study by researchers with the University of Maryland School of Medicine (UMSOM) helps clarify this debate.

Published in The Lancet on January 25, 2024, a phase 3 clinical trial found a single dose of the Vi polysaccharide conjugated to tetanus toxoid vaccine (Vi-TT) is durably efficacious for at least four years among children and shows efficacy in all age groups, including children younger than two years.

"The newly published study supports the long-lasting impacts of a single dose of TCV, even in the youngest children, and offers hope of preventing typhoid in the most vulnerable children," said Kathleen Neuzil, MD, MPH, CVD Director, the Myron M. Levine, MD, DTPH, Professor in Vaccinology at UMSOM and coauthor of the current study, in a press release.

This study found that between February 2018 and September 2018, 28,130 children were vaccinated. After a median follow-up of 4.3 years, 24 (39.7 cases per 100 000 person-years) children in the Vi-TT group and 110 (182,7 cases per 100 000 person-years) children in the MenA group were diagnosed with a first episode of blood culture-confirmed typhoid fever.

In the intention-to-treat population, the efficacy of Vi-TT was 78.3% (95% CI 66·3–86·1), and 163 (129–222) children needed to be vaccinated to prevent one case.

These results support current WHO recommendations in typhoid-endemic areas for mass campaigns among children aged nine months to 15 years, followed by routine introduction in the first two years of life.

Jeri Beales MSN, RN provides education and vaccinations to travelers preparing for their international adventures at Destination Health Travel Clinic near Boston, MA, and offered this advice about typhoid fever to Precision Vax on January 28, 2024, "Trying local cuisines and flavors is the highlight of many international adventures."

"But the food you eat is only as safe as the hygiene of the person preparing it."

"If you have plans to visit a country where typhoid fever is a problem, take the time to get the vaccine because a lot of the risk is literally out of your hands."

"The typhoid fever vaccine is not 100% effective and doesn't protect against all food-borne illness, so you should still be selective in what foods and beverages you consume."

A brief history of typhoid vaccines was discussed in a related Commentary written by Birkneh Tilahun Tadesse, Rita Soares, Barbosa Cardona, and Florian Marks.

Since the 19th century, the first generation vaccine was a whole cell inactivated version, which became less preferred due to significant adverse events.

Second-generation typhoid vaccines included live attenuated vaccines like Ty21a, which can be used in individuals older than six years, and capsular polysaccharide vaccines, which are less immunogenic in children younger than two years.

These limitations prompted the development of typhoid conjugate vaccines (TCVs), which have been shown to induce robust immune responses.

Currently, TCVs that have received WHO prequalification The Typbar TCV® vaccine, developed by Bharat Biotech, received WHO prequalification in 2017.

A University of Oxford study found that the vaccine is safe, 100% immunogenic, and prevents up to 87.1% of infections when using real-life definitions of typhoid fever.

In the United States, very few typhoid cases are reported (157; 2020), mainly related to international travel.

However, the CDC says two typhoid vaccines are available in the U.S.

One is an inactivated (killed) vaccine; the other is a live, attenuated (weakened) vaccine.

Healthcare providers such as doctors, pharmacists, and nurses can help you decide which TCV is best for you.

Unfortunately, there isn't a vaccine that protects people against paratyphoid fever.

The Bill & Melinda Gates Foundation funds the Typhoid Vaccine Acceleration Consortium.

Sub Title:

Typhoid vaccination recommended for certain international travlers

References:

Long-term protection conferred by typhoid conjugate vaccines: a step towards typhoid elimination?

Single dose TCV provides lasting efficacy in children

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US CDC typhoid case map 2020

Typhoid Vaccine Provides Multi-Year Immunity in Children

Donald Hackett — Wed, 10 Aug 2022 14:41:47 +0000

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Kamuzu University of Health Sciences, Malawi

An early release study published today in The Lancet Global Health found the typhoid conjugate vaccine, Typbar TCV®, can offer disease immunity for up to three years in children as young as nine months old.

The phase 3 research conducted in the African country of Malawi found that the TCV vaccine is safe and well tolerated.

Notably, the TCV vaccine can be administered to nine-month-old infants simultaneously as measles-rubella vaccinations without reducing the immune response to either vaccine.

These immunogenicity data can support TCV vaccine introduction in typhoid-endemic countries without data, which is essential, particularly in sub-Saharan Africa, where young children carry a high burden of typhoid fever, stated these researchers.

Typhoid causes more than nine million cases and at least 110,000 deaths yearly.

"It is simply amazing that a single dose of TCV will protect Malawian children for years," said Ngina Nampota, MBBS, MS, lead author of the new research and Study Physician with the Blantyre Malaria Project, an affiliate of Kamuzu University of Health Sciences, Malawi, in a press release on August 10, 2022.

Although whole-cell and polysaccharide typhoid vaccines have been available since the 1980s, uptake in endemic regions has been hindered by moderate and short-lived vaccine protection.

Bharat Biotech International's Typbar TCV contains the Vi-antigen polysaccharide conjugated to a tetanus-toxoid protein carrier that reached WHO prequalification in 2017.

In 2018, the WHO recommended a single-dose TCV for the control of typhoid fever beginning as early as six months of age in typhoid-endemic regions, with priority in countries with the highest typhoid burden disease or a high burden of antimicrobial-resistant S Typhi.

This recommendation was made based on safety and immunogenicity data from a study on Asian children and efficacy data from an adult human challenge study in the U.K.

At the time of this phase 3 trial, there was no data from Africa on TCV efficacy and immunogenicity, including coadministration of TCV with routine vaccines at nine months of age.

However, the response might differ based on regional demographic, environmental, and genetic factors and coadministration with other vaccines.

The next steps are to assess the effect of a booster dose on long-term protection from typhoid fever in children.

While researchers continue to monitor the children vaccinated as part of this study, previous research suggests that TCV protection likely lasts at least five years.

"Our team's goal to protect children against typhoid represents a long-term aim of scientists working across the globe," commented Mark T. Gladwin, M.D., V.P. for Medical Affairs, UM Baltimore, and Dean at UMSOM.

"We are proud of these life-saving accomplishments of scientists in the University of Maryland's Center for Vaccine Development and Global Health, who focus on global efforts to reduce health care disparities."

The Bill & Melinda Gates Foundation partially funded this study with grant OPP1151153.

And this phase 3 study was supported by TyVAC – a partnership between CVD, the Oxford Vaccine Group at the University of Oxford, and the global non-profit PATH. TyVAC was initiated in 2016 as a multi-country project to accelerate the introduction of the TCV vaccine in Gavi-eligible countries.

Typbar TCV® is licensed by Bharat Biotech International Limited, Hyderabad, India.

Additional travel vaccine news is posted at Vax-Before-Travel.

Vax-Before-Travel publishes fact-checked, research-based travel vaccine news translated and curated for international travelers.

Sub Title:

Typbar TCV vaccine immunity in children can last three years

References:

Safety and immunogenicity of a typhoid conjugate vaccine among children aged 9 months to 12 years in Malawi

TypBar TVC vaccine

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Frontline Antibiotics Losing to Typhoid Mutations

Karen McClorey Hackett — Fri, 08 Jul 2022 16:45:41 +0000

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‘Global response’ needed as typhoid evades antibiotics

The bacteria that causes typhoid fever is becoming increasingly resistant to antibiotics used to treat the disease, with resistant strains spreading to hundreds of countries in the past three decades, according to an analysis published by The Lancet Microbe in June 2022.

This recent study shows how resistant strains from South Asia, where the disease is endemic, have spread 200 times to other countries since 1990.

Lead author Jason Andrews, an infectious disease specialist from Stanford University, told SciDev.Net’s Dann Okoth on July 4, 2022, “The repeated acquisition of antimicrobial resistance among S.Typhi and spread across borders is concerning.”

“We have very few antibiotics left that are effective against typhoid.”

Typhoid fever is a life-threatening infection caused by the bacterium Salmonella Typhi (S.Typhi), leading to over 128,000 related fatalities, according to the World Health Organization.

To isolate the drug-resistant typhoid strains, the researchers performed genome sequencing on 3,489 S.Typhi candidates obtained from blood samples collected between 2014 and 2019 from people in Bangladesh, India, Nepal, and Pakistan with confirmed cases of typhoid fever.

The researchers stated it is ‘the largest ever examination of the S. Typhi bacterium.’

They showed that of the 7,658 strains studied, genetic analysis techniques were resistant to typical frontline antibiotics like ampicillin, chloramphenicol, and trimethoprim/sulfamethoxazole.

The findings show that resistant S. Typhi strains have spread between countries at least 197 times since 1990, with strains that often occurred in South Asia and South-East Asia, East and Southern Africa spreading to countries including the USA, the U.K., and Canada.

The highly contagious disease usually spreads via contaminated water and food or person-to-person contact in areas with poor sanitation.

And Multidrug-resistant (MDR) typhoid is being seen in Pakistan.

To alert international travelers, the U.S. CDC issued a Watch - Level 1, Practice Usual Precautions notice regarding Pakistan’s extensively drug-resistant (XDR) typhoid fever outbreak.

Extensively drug-resistant infections do not respond to most antibiotics, says the CDC.

“If MDR strains acquire azithromycin resistance, we will have no effective oral antibiotics left for treating typhoid,” Andrews added. According to the study, mutations causing resistance to azithromycin have emerged seven times in the past 20 years.

Furthermore, typhoid strains resistant to quinolones – a class of antibiotics that act against a wide range of disease-causing bacteria – have risen and spread at least 94 times since 1990, according to the study.

It says strains resistant to quinolones accounted for more than 85% of S.Typhi in Bangladesh by the early 2000s, rising to more than 95% in India, Pakistan, and Nepal by 2010.

Quinolones became the mainstay of treatment for suspected typhoid cases in the 1990s since they were highly effective against the disease, says Andrews.

The CDC says, ‘If you are going to South Asia, including Pakistan, protect yourself by getting a typhoid fever vaccination before your trip and taking extra care to follow safe food and water guidelines.’

In the USA, two types of typhoid fever vaccines are available:

Oral vaccine: Can be given to people at least six years old. It consists of four pills taken every other day, should be finished at least one week before travel, and requires a booster every five years.
Injectable vaccine: Can be given to people at least two years old and should be given at least two weeks before travel, and requires a booster every two years

If you were vaccinated in the past, ask your doctor or pharmacist if it is time for booster vaccination, says the CDC.

This article is republished from SciDev.Net under a Creative Commons license.

Vax-Before-Travel publishes fact-checked research-based travel vaccine news.

Sub Title:

Resistant S. Typhi bacterium strains found in the USA, U.K., and Canada

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WHO: Typhoid

TYPHOID VACCINES

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XDR Typhoid Fever Cases Found in the USA

Don Hackett — Thu, 18 Feb 2021 22:29:22 +0000

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XDR Typhoid Fever in Travelers

The US Centers for Disease Control and Prevention (CDC) announced nine extensively drug-resistant (XDR) typhoid fever cases in the USA unrelated to international travel.

Additionally, the CDC’s Health Advisory Network issued an Alert on February 12, 2021, stating an ongoing outbreak of XDR typhoid fever has sickened more than 5,000 people in the Islamic Republic of Pakistan since 2016.

As of January 14, 2021, the CDC received 71 reports of XDR Typhi infection in the USA, with specimens obtained from February 2018 through November 2020. Among 67 patients with known travel history, 87% had traveled to Pakistan in the 30 days before illness began.

However, the nine patients from six states (NY, CA, IL, MD, NJ, and TX) reported that they had not traveled to Pakistan or any other country. Susceptibility testing of these specimens showed the same resistance pattern described in Pakistan.

Most people in the USA diagnosed with typhoid fever acquired it during international travel. However, CDC has not identified linkages among these patients or a common infection source.

Before the outbreak in Pakistan, no case of ceftriaxone-resistant Typhi infection had been identified in the United States. An unrelated cluster of ceftriaxone-resistant Typhi infections linked to Iraq has been reported in the USA and the United Kingdom.

According to the CDC, up to 30% of people with typhoid fever will die without appropriate antibiotic treatment.

The CDC states ‘Clinicians should consider empiric treatment with a carbapenem, azithromycin, or both agents for suspected typhoid fever in patients who did not travel out of the USA and those who traveled to Pakistan or Iraq.

Ceftriaxone remains an appropriate empiric treatment option for patients who traveled to countries other than Pakistan and Iraq.

Taking antibiotics will not prevent typhoid fever; they only help treat it.

‘Vaccinate patients who are at high risk for typhoid fever, including those traveling to parts of the world where typhoid fever is common, those in close contact with a typhoid carrier, and those who might work with Typhi in a laboratory, says the CDC.

Two typhoid fever vaccines are available in the United States, which are not 100% effective since Typhoid vaccines lose effectiveness over time.

Vivotif oral vaccine: Can be given to people at least six years old. It consists of four pills taken every other day and should be finished at least one week before travel and requires a booster every five years.

Typhim IV injectable vaccine: Can be given to people at least two years old and should be given at least two weeks before travel. The injectable vaccine requires a booster every two years. If you were vaccinated in the past, ask your doctor if it is time for a booster vaccination.

As of September 2020, the CDC issued a Level 1, Practice Usual Precautions, for anyone visiting Pakistan. This advisory says, ‘All travelers to Pakistan are at risk of getting XDR typhoid fever. Those visiting friends or relatives are at a greater risk than tourists or business travelers.’

PrecisionVaccinations publishes research-based vaccine news.

Sub Title:

Extensively Drug-Resistant Salmonella Typhi infections found among USA residents without international travel

References:

CDC: XDR Typhi infection

CDC: Extensively Drug-Resistant Typhoid Fever in Pakistan

CDC: Update on XDR Salmonella SeroType Typhi Infections Among Travelers to or from Pakistan

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Accurately Diagnosing Typhoid Requires Enhanced Testing

Danielle Reiter RN — Fri, 17 Jan 2020 15:42:09 +0000

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Under-detection of blood culture-positive enteric fever cases: The impact of missing data and methods for adjusting incidence

A new study focused on typhoid and paratyphoid fevers indicates cases can be missed when patients don't seek medical care, or seek medical care and don't have a blood culture test.

Which means, the true burden of typhoid related disease could be underestimated.

This is important news since the World Health Organization (WHO) estimates about 22 million cases of typhoid fever and 5 million cases of paratyphoid fever occur worldwide each year, causing about 200,000 fatalities.

Typhoid and paratyphoid fever are infections caused by the bacteria Salmonella enterica Typhi and S. Paratyphi.

Researchers writing in PLOS Neglected Tropical Diseases on January 16, 2020, have now calculated inflation factors that can be used to adjust these typhoid incidence rates to account for under-detection.

Merryn Voysey, the Lead Statistician at the Oxford Vaccine Group, University of Oxford, UK, and colleagues used data from an ongoing Typhoid Vaccine Acceleration Consortium (TyVAC) clinical trial of a typhoid vaccine in Nepal.

During the first year of passive surveillance, data was collected on 2,393 fever presentations. Overall, 1615 (68%) of patients had blood cultures.

The models used in this study revealed that patients who had blood taken were 1.87 times more likely to be positive for Salmonella than those without blood cultures.

"Crude typhoid incidence estimates should be adjusted for both the proportion of cases that go undetected due to missing blood cultures as well as the lower likelihood of culture-positivity in the group with missing data," the researchers say.

In the UK, the NHS says a diagnosis of typhoid feve r can usually be confirmed by analyzing samples of blood, stools, or urine. These will be examined for the Salmonella typhi bacteria that cause the condition.

In countries with a high incidence rate of typhoid-related diseases, vaccine programs are used to control typhoid fever.

To address this need, the WHO issued a revised policy on typhoid vaccines in 2018. This policy follows evidence-based recommendations that prevention through vaccination is one of the most effective solutions to reduce the burden of typhoid in endemic areas.

In a previous, related study of the typhoid conjugate vaccine (TCV) December 5, 2019, showed a single vaccination to be 81 percent safe and effective in reducing typhoid in children between the ages of 9 months and less than 16 years.

The researchers noted that these were preliminary results and that the study will continue to follow the participants for the next 2 years.

The US Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices recommends 2 typhoid fever vaccines, an oral vaccine, Vivotif, and an injectable vaccine, Typhim VI.

Neither vaccine is 100 percent effective, so travelers to endemic countries should also practice safe eating and drinking habits while traveling abroad, says the CDC.

Travelers to Asia, Africa, and Latin America are especially at risk, and the highest risk for typhoid is in south Asia.

If you get sick after returning to the United States, seek medical care and tell your healthcare provider where and when you traveled, says the CDC.

In the USA, approximately 350 culture-confirmed cases of typhoid fever and 90 cases of paratyphoid fever caused by Paratyphi A are confirmed annually.

Study funding: The authors thank the Bill & Melinda Gates Foundation (OPP1151153) for funding TyVAC, including the Nepal trial; the Wellcome Trust and the Bill & Melinda Gates Foundation for funding of The Strategic Typhoid Alliance across Africa and Asia, which supported the surveillance that underpins this trial; and the National Institute for Health Research Oxford Biomedical Research Centre. MV is funded by a National Institute of Health Research (NIHR) Doctoral Research Fellowship (DRF-2015-08-048). The funders had no role in study design, data collection, and analysis, decision to publish, or preparation of the manuscript.

The researchers disclosed various industry relationships.

The Typhoid Vaccine Acceleration Consortium (TyVAC), a partnership between the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, the Oxford Vaccine Group at the University of Oxford, and PATH, an international nonprofit, aims to accelerate the introduction of new typhoid conjugate vaccines (TCVs) as part of an integrated approach to reducing the burden of morbidity and mortality from typhoid in countries eligible for support from Gavi, the Vaccine Alliance.

Typhoid travel vaccine news published by Vax-Before-Travel

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Blood cultures are very beneficial when diagnosing typhoid and paratyphoid fever

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CDC: Typhoid Fever

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Just One Typhoid Vaccination Found Very Effective in Nepal

Danielle Reiter RN — Fri, 06 Dec 2019 16:20:54 +0000

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Phase 3 Efficacy Analysis of a Typhoid Conjugate Vaccine Trial in Nepal

An extensive study of the typhoid conjugate vaccine (TCV) has shown a single dose to be 81 percent safe and effective in reducing typhoid in children between the ages of 9 months and less than 16 years.

Announced on December 5, 2019, and published in the New England Journal of Medicine, this interim analysis involved 20,019 children who were randomly given one of two vaccines; half received TCV and half received the Group A meningococcal (MenA) vaccine, which was the study’s control group.

Additionally, in this study’s immunogenicity subgroup, the seroconversion (a Vi IgG level that at least quadrupled 28 days after vaccination) was reported at 99 percent in the TCV group and 2 percent in the MenA vaccine group.

The researchers noted that these were preliminary results and that the study will continue to follow the participants for the next 2 years.

These results show the TCV vaccine has the potential to significantly reduce the burden of typhoid in high-risk populations. Typbar TCV is a vaccine containing polysaccharide of Salmonella typhi Ty2 conjugated to Tetanus Toxoid.

An estimated 26 million cases of typhoid fever and 5 million cases of paratyphoid fever occur worldwide each year, causing about 215,000 deaths.

Furthermore, this data is especially timely with the recent spread of extensively drug-resistant typhoid, which threatens child health in affected regions.

To address this need, the World Health Organization (WHO) issued a revised policy on typhoid vaccines in 2018. This policy follows evidence-based recommendations that prevention through vaccination is one of the most effective solutions to reduce the burden of typhoid in endemic areas.

The good news is the government of Pakistan said it was launching an Expanded Program on Immunization for the TCV vaccination campaign in the Sindh province.

Andrew Pollard, Professor of Paediatric Infection and Immunity at Oxford University’s Department of Paediatrics, said in a related statement, 'This is the first study to show that a single dose of TCV is safe, immunogenic, and effective, which provides clear evidence that vaccination will help efforts to control this serious disease and is a strong endorsement of the WHO policy for vaccine implementation.'

'The efficacy of these results in an endemic population adds to a growing body of evidence supporting the use of TCV to reduce disease and save lives in populations that lack clean water and improved sanitation,' said Dr. Kathleen Neuzil, M.D., director of the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine and director of TyVAC.

Neither vaccine is 100 percent effective, so travelers to endemic countries should also practice safe eating and drinking habits while traveling abroad, says the CDC

Caused by the bacterium Salmonella Typhi, Typhoid fever is a serious disease that is spread by contaminated food and water. Humans are the only source of these bacteria.

Symptoms of typhoid fever often include high fever, weakness, stomach pain, headache, cough, and loss of appetite. People may have diarrhea or constipation.

The incubation period of typhoid and paratyphoid infections is 6–30 days, says the CDC.

If you travel abroad and get sick, seek medical care ASAP.

If you get sick after returning to the United States, seek medical care and tell your health care provider where and when you traveled, says the CDC.

In the USA from 2008–2015, approximately 350 culture-confirmed cases of typhoid fever and 90 cases of paratyphoid fever caused by Paratyphi A were reported each year.

Funding for this study was provided by a grant from the Bill & Melinda Gates Foundation.

The investigational vaccine Typbar-TCV is licensed by Bharat Biotech International Limited, Hyderabad, India.

Travel vaccine news is published by Vax-Before-Travel

Sub Title:

Typbar typhoid conjugate vaccine TCV shown to be 81 percent safe and effective in reducing typhoid in children

References:

TyVAC Nepal: typhoid vaccine study

Typhoid vaccine over 81% effective in tackling disease in Nepal

Typhoid Vaccine May Offer Extended Protections

XDR Typhoid Fever Outbreak Confirmed in the Islamic Republic of Pakistan

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Enteric Fever Vaccine Candidate to Launch Phase 1 Study

Don Hackett — Tue, 26 Nov 2019 20:26:14 +0000

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Prokarium Announces MHRA Acceptance to Run Phase I Trial of Lead Vaccine Against Enteric Fever

Kelley Lu, PharmD

A London based biotechnology company has received Clinical Trial Authorization acceptance from the UK Medicines and Healthcare products Regulatory Agency to conduct a first-in-human Phase I trial for Entervax™, a vaccine candidate against enteric fever also known as typhoid.

Entervax is an oral, bivalent vaccine based on the Vaxonella® platform and is the combination of Prokarium’s proprietary strain ZH9 (Salmonella enterica serovar Typhi ZH9), plus a novel strain modified to express antigens specific to S. Paratyphi A.

The company, Prokarium, said in a press release published on November 26, 2019, it anticipates dosing of the 1st subject to begin in the first quarter of 2020.

Enteric fever is a preventable illness caused predominantly by Salmonella enterica serovars Typhi and Paratyphi A, accounts for at least 20 million cases annually and is the most common bacterial bloodstream infection in South Asia, said the company.

The endemic population in low- and middle-income countries (LMICs) is about 5.6 billion of which 1.6 billion are at high-risk of developing a typhoid infection.

Misdiagnoses and lack of efficacy of first-line treatments have led to an outbreak of extensively drug-resistant strains and vaccination is the most effective medical intervention to stop the spread of the disease.

This is complicated by the spread of an extensively drug-resistant strain which is creating a growing global demand for new vaccines.

Entervax™ has the potential to provide broader protection for these at-risk individuals in LMICs and travelers to those countries.

Following this Phase I trial, Prokarium plans to run a Phase Ib age-descending, dose-escalation study in South Asia.

The new clinical trial is part of a collaboration between Prokarium and the Wellcome Trust, which invested £4.6m earlier in 2019.

Prokarium is a developer of targeted vaccines against infectious diseases. Its lead candidate is Entervax, a vaccine against enteric fever.

Enteric Fever (Typhoid) news published by Precision Vaccinations

Sub Title:

Prokarium Entervax is an oral, bivalent vaccine based on the Vaxonella platform

References:

Enteric Fever Caused by Salmonella enterica Serovars with Reduced Susceptibility of Fluoroquinolones at a Community Based Teach

CDC: Typhoid Fever and Paratyphoid Fever

WHO: Typhoid fever

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Which Travel Vaccinations Are Important This Winter?

Danielle Reiter RN — Mon, 25 Nov 2019 15:42:11 +0000

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Get your vaccinations before you travel for holidays

The winter holiday season is arriving and so are holiday travel trips. If you plan to travel abroad, there may be required vaccination prior to visiting an infectious disease hot-spot, such as Brazil.

‘It’s important to talk to your doctor about vaccines to keep you safe during and after international travel,’ says Drs. Megan Berman and Richard Rupp, at the University of Texas Medical Branch, located in Galveston, Texas.

These health experts said in Vaccine Smarts published on November 19, 2019, ‘routine vaccinations, based on age and health conditions, are recommended for all travelers.’

‘This recommendation is particularly important considering that many countries don’t have robust pediatric vaccination programs, so travelers will not benefit from the herd immunity afforded by such programs.’

Excerpts from this informative article are inserted below:

Tetanus:

Tetanus vaccination is recommended every 10 years, but international travelers should be vaccinated if it has been five or more years since the last booster dose.
Tetanus is found in the environment, and the toxin it releases during infection causes lockjaw. Travelers should receive the vaccine in case of an accidental injury because it may be difficult to find good medical care.
The vaccine also includes protection against diphtheria, a serious throat infection, and may include protection against pertussis (whooping cough), which causes prolonged cough in adults.

Typhoid:

Typhoid vaccination is recommended for travel in the developing world. Typhoid fever is a potentially lethal illness with the primary symptoms of fever, headache, and diarrhea.
Typhoid occurs in areas with underdeveloped sewage and water systems (for example, regions of Africa, South America, South and Southeast Asia, and the Caribbean).
Typhoid is transmitted by the fecal-oral route, meaning an infected food handler practicing poor bathroom hygiene can transmit the disease to others — remember Typhoid Mary.
Typhoid vaccines are available as an injection or pill. The injection is a killed (inactivated) germ and is approved for those older than 2 years of age. Protection lasts for two years.
The pill may be better for frequent travelers as it protects for five years. The pill is approved for people 6 years and older. It’s a live but weakened germ, and so it cannot be used if someone has a weak immune system.
The pill is tricky to take correctly. It needs to be refrigerated. The pill is taken every other day, one hour prior to a meal with a cold or lukewarm drink, for a total of four doses.

Hepatitis A:

Since 2008, it has been recommended routinely for children after their first birthday. This vaccine works incredibly well — after two doses the vaccine is nearly 100 percent effective.
The virus attacks the liver and can cause liver failure. Hepatitis A is common in Africa, Asia, Central and South America, the Middle East, and the Western Pacific.
Travelers who haven’t received the vaccine should receive two doses six months apart. Those who cannot get both doses before leaving should not fret as even one dose offers excellent protection.
The second dose can be given upon returning to the USA.

Other vaccines may be recommended depending on the region to be visited and on planned activities. It’s important to speak with your healthcare provider about vaccines and other precautionary measures, such as those to protect against malaria or diarrhea, concluded Drs. Berman and Rupp.

Specific vaccine details can be easily searched at Precision Vaccinations.

The US Centers for Disease Control and Prevention says any vaccine can cause side effects, which should be immediately reported to a healthcare provider.

Vaccine Smarts is written by Sealy Institute for Vaccine Sciences faculty members Drs. Megan Berman, an associate professor of internal medicine, and Richard Rupp, a professor of pediatrics at the University of Texas Medical Branch.

For questions about vaccines, email vaccine.smarts@utmb.edu.

Travel Vaccine news published by Vax-Before-Travel

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Travel vaccination advice and suggestions from UTMB Vaccine Smarts

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10 Million Pakistan Children To Receive Typhoid Vaccination

Danielle Reiter RN — Sat, 16 Nov 2019 14:00:26 +0000

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Govt is all set to launch typhoid vaccination campaign

Typhoid fever is a continuing public health threat in many low- and middle-income countries around the world.

But, routine vaccine prevention programs have not been implemented in most countries.

To address this shortcoming, the World Health Organization (WHO) issued a revised policy on typhoid vaccines in 2018. This new policy follows evidence-based recommendations by the WHO Strategic Advisory Group of Experts on immunization for routine and catch-up vaccination with typhoid conjugate vaccines (TCV).

Prevention through vaccination is one of the most effective solutions to reduce the burden of typhoid in endemic areas, says the WHO.

The good news is the government of Pakistan is launching an Expanded Program on Immunization for TCV vaccination campaign in the Sindh province, beginning November 18, 2019, reported Incpak on November 13, 2019.

Sindh is one of the 4 provinces of Pakistan, located in the southeast of the country.

More than 15,000 people have been affected in the current outbreak, the first-ever reported ceftriaxone-resistant typhoid outbreak.

Over 8,000 vaccination teams working with local Union Councils throughout Sindh will target 10.1 million children, disclosed by Dr. Akram Sultan, Project Director, in Sindh.

After first being introduced in the Sindh Province, which is the center of an ongoing extensively drug-resistant (XDR) typhoid outbreak, the TCV vaccine will next be introduced in Punjab Province in 2020, and then nationally in 2021.

XDR infections do not respond to most antibiotics.

The WHO prequalified the first conjugate vaccine to prevent typhoid fever called Typbar-TCV® developed by Indian pharmaceutical company Bharat Biotech, in 2018.

The Typbar-TCV vaccine contains polysaccharide of Salmonella typhi Ty2 conjugated to Tetanus Toxoid.

The Typbar-TCV vaccine is a 1-dose, injected intramuscularly, that is expected to provide long-lasting immunity in adults, children, and infants 6 months of age and older.

The WHO has recommended the TCV vaccine for use in all typhoid-endemic countries because of its higher efficacy compared to previously used typhoid vaccines.

Additionally, the Typbar-TCV vaccine should also help to curb the frequent use of antibiotics for treatment of presumed typhoid fever, and thus help slow the increase in antibiotic resistance in Salmonella Typhi, says the WHO.

About 300 people get typhoid fever in the United States each year. Most typhoid cases in the USA are from people who have recently traveled internationally, says the Centers for Disease Control and Prevention (CDC).

Typhoid, a serious illness caused by Salmonella Typhi, is spread through contaminated food and water. In addition, WASH solutions (water, sanitation, and hygiene) should be promoted alongside TCV introduction.

Typhoid symptoms of typhoid include lasting high fevers, weakness, stomach pains, headache, and loss of appetite. Some patients have constipation, and some have a rash. Internal bleeding and death can occur but are rare, reports the CDC.

Typhoid vaccines are recommended for:

Travelers to parts of the world where typhoid is common Note: typhoid vaccine is not 100% effective and is not a substitute for being careful about what you eat or drinkn
People in close contact with a typhoid carrier
Laboratory workers who work with Salmonella Typhi bacteria

There are two vaccines to prevent typhoid. One is an inactivated (killed) vaccine gotten as an injection and the other is a live, attenuated (weakened) vaccine, which is taken orally.

The CDC says any vaccine can cause side effects, which should be reported to a healthcare provider.

Typhoid Vaccine news published by Vax-Before-Travel

Sub Title:

Pakistan launching Expanded Program on Immunization for TCV vaccinations in Sindh province

References:

Introduction of Typhoid Conjugate Vaccines in Africa and Asia

Toward Control? The Prospects and Challenges of Typhoid Conjugate Vaccine Introduction

CDC: Extensively Drug-Resistant Typhoid Fever in Pakistan

WHO: Typhoid vaccine prequalified

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Ireland Confirms 23 Typhoid Fever Cases

Danielle Reiter RN — Thu, 10 Oct 2019 12:21:07 +0000

Reviewer:

Increase in typhoid notifications in travellers returning from Pakistan

The Health Protection Surveillance Centre in Ireland reported an increase in typhoid fever notifications in travelers returning from Pakistan.

According to the Irish authorities on October 9, 2019, there have been 23 cases of Salmonella enterica serovar Typhi (S. Typhi) in 2019.

This is the first time that cases of XDR typhoid fever have been identified by the national reference laboratory in Ireland.

The European Centre for Disease Prevention and Control (ECDC) reported 12 of these cases had a recent travel history to Pakistan.

Unfortunately, 3 of these 12 cases of typhoid fever with travel history in Pakistan were infected with extensively drug-resistant (XDR) strains.

According to the WHO/EMRO bulletin, Pakistan is experiencing a continuous surge of XDR S. Typhi since 2016.

As of August 2019, 10,365 cases of XDR typhoid fever were reported from 23 districts in Sindh province, with the Karachi district being the most affected, having 67 percent of the cases.

Pakistan is the world’s 6th-most populous country with a population exceeding 210 million people, located in South Asia.

The XDR S. Typhi strain acquired a plasmid that confers resistance to multiple antibiotics, including the first-line antibiotics chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole, as well as fluoroquinolones and third-generation cephalosporins, says the ECDC.

The strain remained susceptible to azithromycin and carbapenems.

The increased resistance in typhoid fever limits treatment options and poses a threat to international spread.

In response, the US Centers for Disease Control and Prevention (CDC) issued a Level 1 Travel Alert regarding traveling to Pakistan in 2019.

This ‘Practice Usual Precautions’ Travel Alert published on September 30, 2019, is very important since, in rare cases, typhoid fever can be fatal.

According to the Pakistan Tourism Development Corporation, about 1.75 million tourists visited Pakistan in 2017 alone.

The CDC says ‘if you are going to South Asia, including Pakistan, protect yourself against typhoid infection by getting a typhoid fever vaccination.’

The CDC’s Advisory Committee on Immunization Practices (ACIP) recommends 2 typhoid fever vaccines, an oral vaccine, Vivotif, and an injectable vaccine, Typhim VI.

The oral vaccine Vivotif is approved for people 6 years of age or older and should be taken as directed, at least 1 week before departure.

The injectable vaccine is approved for people 2 years of age or older. Travelers should receive the injectable vaccine Typhim VI at least 2 weeks before departure.

Neither vaccine is 100 percent effective, so travelers should also practice safe eating and drinking while traveling abroad, says the ACIP.

Typhoid fever is a serious disease caused by the bacterium Salmonella Typhi, spread by contaminated food and water. Humans are the only source of these bacteria.

The incubation period of typhoid and paratyphoid infections is 6–30 days, says the CDC.

Symptoms of typhoid fever often include high fever, weakness, stomach pain, headache, cough, and loss of appetite. People may have diarrhea or constipation.

If you travel abroad and get sick while traveling, seek medical care ASAP.

If you get sick after returning to the United States, seek medical care and tell your health care provider where and when you traveled. Do not prepare food for other people, says the CDC.

An estimated 26 million cases of typhoid fever and 5 million cases of paratyphoid fever occur worldwide each year, causing 215,000 deaths.

Also, the CDC says to ensure you are up-to-date on several vaccinations before visiting Pakistan. These vaccines and related medications can be found at most travel pharmacies in the USA.

From a security perspective, the US Department of State issued a ‘Reconsider Travel to Pakistan’ Level 3 Advisory regarding civil unrest on April 9, 2019.

Moreover, some areas of Pakistan have a ‘Do Not Travel’ Level 4 Advisory.

Travel Alert news is published by Vax-Before-Travel.

Sub Title:

XDR typhoid fever has been identified in Ireland for the first time

References:

Increase of XDR Typhoid fever in travellers returning from Pakistan

US Department of State: Pakistan - Level 3: Reconsider Travel

XDR Typhoid Fever Outbreak Confirmed in the Islamic Republic of Pakistan

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XDR Typhoid Fever Outbreak Confirmed in the Islamic Republic of Pakistan

Danielle Reiter RN — Sun, 06 Oct 2019 18:08:04 +0000

Reviewer:

CDC: Health Information for Travelers to Pakistan

The U.S. Centers for Disease Control and Prevention (CDC) issued a Level 1 Travel Alert regarding the ongoing outbreak in the Islamic Republic of Pakistan, of Extensively Drug-Resistant (XDR) Typhoid Fever.

This ‘Practice Usual Precautions’ Travel Alert published on September 30, 2019, is very important since XDR infections do not respond to most antibiotics, such as ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, ciprofloxacin, and ceftriaxone.

And in rare cases, typhoid fever can be fatal.

The CDC says people from the United States, Canada, United Kingdom, Denmark, and Australia with a travel history to Pakistan have reported XDR typhoid infections. According to the Pakistan Tourism Development Corporation, about 1.75 million tourists visited Pakistan in 2017 alone.

Pakistan is the world’s 6th-most populous country with a population exceeding 210 million people, located in South Asia.

Pakistan’s current XDR typhoid fever outbreak began in Hyderabad, which is a city of Sindh province, part of the Islamic Republic of Pakistan, during November 2016.

The CDC says ‘if you are going to South Asia, including Pakistan, protect yourself against typhoid infection by getting a typhoid fever vaccination.’

The CDC’s Advisory Committee on Immunization Practices (ACIP) recommends 2 typhoid fever vaccines, an oral vaccine, Vivotif, and an injectable vaccine, Typhim VI.

The oral vaccine Vivotif is approved for people 6 years of age or older and should be taken as directed at least 1 week before departure.

The injectable vaccine Typhim VI is approved for people 2 years of age or older. Travelers should receive the injectable vaccine Typhim VI at least 2 weeks before departure.

Neither vaccine is 100% effective, so travelers should also practice safe eating and drinking habits while traveling abroad, says the ACIP.

Typhoid fever is a serious disease caused by the bacterium Salmonella Typhi, spread by contaminated food and water. Humans are the only source of these bacteria.

The incubation period of typhoid and paratyphoid infections is 6–30 days, says the CDC.

Symptoms of typhoid fever often include high fever, weakness, stomach pain, headache, cough, and loss of appetite. People may have diarrhea or constipation.

If you travel abroad and get sick while traveling, seek medical care ASAP.

If you get sick after returning to the United States, seek medical care and tell your health care provider where and when you traveled. Do not prepare food for other people, says the CDC.

An estimated 26 million cases of typhoid fever and 5 million cases of paratyphoid fever occur worldwide each year, causing 215,000 deaths.

In the USA from 2008–2015, approximately 350 culture-confirmed cases of typhoid fever and 90 cases of paratyphoid fever caused by Paratyphi A were reported each year.

Additionally, during the week ending September 11, 2019, Pakistan confirmed 4 wild poliovirus type 1 (WPV1) cases and 28 WPV1-positive environmental samples.

And, on September 3, 2019, a total of 7.1 million Pakistani children were successfully administered polio drops, which means they are protected against the poliovirus.

Also, the CDC says to ensure you are up-to-date on several vaccinations before visiting Pakistan.

These vaccines and related medications can be found at most travel pharmacies in the USA.

From a security perspective, the U.S. Department of State issued a ‘Reconsider Travel to Pakistan’ Level 3 Advisory regarding civil unrest on April 9, 2019. Moreover, some areas of Pakistan have a ‘Do Not Travel’ Level 4 Advisory, such as:

Balochistan province and Khyber Pakhtunkhwa (KPK) province, including the former Federally Administered Tribal Areas (FATA), due to terrorism and kidnapping.
The Azad Kashmir area, due to terrorism and the potential for armed conflict.

CDC and State Department Travel Alert news is published by Vax-Before-Travel.

Sub Title:

Pakistan Travel Alert regarding extensively drug-resistant (XDR) typhoid fever issued by CDC

References:

CDC: Extensively Drug-Resistant Typhoid Fever in Pakistan

US Department of State: Pakistan - Level 3: Reconsider Travel

CDC: Typhoid & Paratyphoid Fever

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CDC Watch - Level 1, Practice Usual Precautions

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Typhoid Vaccinations Can Be A Cost-Effective Solution

Don Hackett — Tue, 28 May 2019 19:44:32 +0000

Reviewer:

Cost-effectiveness of routine and campaign use of typhoid Vi-conjugate vaccine in Gavi-eligible countries: a modelling study

Researchers at the Yale School of Public Health say introducing a typhoid conjugate vaccine (TCV) into routine child vaccine schedules and conducting vaccination campaigns for young teenagers is a cost-effective solution to reduce the burden of typhoid.

This Yale study published on May 24, 2019, is the 1st comprehensive analysis of the cost-effectiveness of different typhoid vaccination strategies for 54 countries hit hardest by typhoid.

In the Yale modeling study, the researchers compared various strategies:

no vaccination
routine immunization at 9 months
routine immunization at 9 months with catch-up campaigns to either age 5 years or 15 years

An optimum strategy for a country was considered one that ‘maximized the average net monetary benefit.’ TCV vaccination was likely to be cost-effective in countries with 300 or more typhoid cases per 100,000 person-years.

Individual country reports on the cost-effectiveness and potential benefits of the TCV vaccine can be found at Together We Can Take On Typhoid.

The typhoid conjugate vaccine, Typbar-TCV®, was recently approved by the World Health Organization and is currently recommended as part of an integrated approach to controlling the disease along with improvements in water, sanitation, and hygiene.

Typbar TCV is a vaccine containing polysaccharide of Salmonella typhi Ty2 conjugated to Tetanus Toxoid. Vi Capsular polysaccharide of Salmonella typhi alone elicit B cell responses, but the conjugation of bacterial polysaccharide to a protein carrier provides foreign peptide antigens that are presented to the immune system eliciting antigen-specific CD4+ Th cells, referred to as T-dependent antibody responses.

A hallmark of T-dependent responses, which are also elicited by toxoid is to induce both higher-affinity antibodies and long-term immune memory.

The Typbar-TCV vaccine overcomes many of the limitations of earlier typhoid vaccines, such as:

offers longer-lasting protection
requires fewer doses and is suitable for children as young as 6 months of age
allowing it to be included in routine childhood immunization programs

“We have provided all of the information for decision-makers to evaluate whether the typhoid conjugate vaccine is a good value,” said Virginia Pitzer, associate professor of epidemiology at the Yale School of Public Health and the study’s senior author.

“Now each country will have the information needed to decide for itself whether or not to apply for Gavi funding to introduce the vaccine.”

Typhoid is a serious and sometimes fatal disease caused by the bacteria Salmonella Typhi.

It impacts over 10 million people a year and is spread through contaminated food and water, usually due to inadequate sanitation and water infrastructures in low- and middle-income countries.

While the global incidence of typhoid has declined in recent years, prolonged multi-year outbreaks continue to pose a public health threat, says the WHO.

Recent typhoid vaccine news:

“Expanding access to, and coverage of, TCVs can protect children and adolescents from illness, reduce the need for antibiotics, slow emergence of drug-resistant strains, and save lives,” said Dr. Kathleen Neuzil, director of the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine and director of the Typhoid Vaccine Acceleration Consortium (TyVAC).

TyVAC, one of the funders of the study, is a partnership between the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, the Oxford Vaccine Group at the University of Oxford and PATH, an international nonprofit, that aims to accelerate the introduction of TCVs into low-resource settings.

The study was led by Pitzer and Professor A. David Paltiel, co-directors of the Yale School of Public Health’s Modeling Concentration, in close collaboration with a team in the Center for Health Economics and Modelling Infectious Diseases (CHERMID) at the University of Antwerp in Belgium. No conflicts of interest were disclosed.

Sub Title:

Bharat Biotech typhoid vaccine Typbar-TCV was approved by the WHO in 2018

References:

Vaccine Is a Cost-Effective Solution for Countries Burdened by Typhoid

Typhoid vaccine prequalified

About Typbar TCV

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Zimbabwe’s Typhoid Vaccination Campaign Concludes Successfully

Don Hackett — Wed, 06 Mar 2019 22:46:18 +0000

Reviewer:

Africa’s first-ever mass typhoid fever vaccination campaign ends in Zimbabwe

The first-ever vaccination campaign in Africa against typhoid fever promises to be a new layer of protection, especially for families living in conditions of unsafe water and sanitation, says the World Health Organization (WHO).

This 8-day vaccination campaign took place in high-density Harare suburbs between February 25 to March 4, 2019.

The WHO vaccinated 370 000 people, mostly adolescents, reaching 73 percent of the targeted population in the first 6 days of the campaign.

This vaccination campaign is important since more than 1,682 suspected and 39 confirmed typhoid fever cases were reported in Zimbabwe’s capital city between September 2018 and January 2019.

“Zimbabwe is the first country in Africa to benefit from the mass typhoid vaccination, which has been proven safe and effective,” says WHO Country Representative Dr. Alex Gasasira.

The Typbar-typhoid conjugate vaccine against typhoid is new, and, unlike the routine typhoid immunization, it has proven safe for children older than 6 months of age.

“We noted with concern that typhoid cases in Harare had been on the increase, with the peak reached in December 2018,” explains Dr. Obadiah Moyo, Minister of Health and Child Care.

“In order to prevent further spread of typhoid, we decided to introduce the typhoid conjugate vaccine in high-risk areas while at the same time promoting water provision, sanitation, and good hygiene.”

Typhoid fever is a bacterial infection caused by Salmonella Typhi that is estimated to cause between 128,000-190,000 deaths annually, says the WHO.

In the USA, Vivotif is a Typhoid Vaccine Live Oral Ty21a authorized by the Food and Drug Administration for immunization of adults and children greater than 6 years of age against disease caused by Salmonella typhi.

Additionally, the Centers for Disease Control and Prevention has issued various Travel Alerts regarding Typhoid Fever outbreaks around the world.

On February 13, 2019, the CDC updated its vaccine recommendations when visiting Zimbabwe, which includes the Typhoid vaccination.

Pre-trip, vaccine and medication counseling appointments can be scheduled at Vax-Before-Travel.

And, U.S. citizens who travel abroad should always have a contingency plan for emergency situations, such as this Traveler’s Checklist.

Sub Title:

Vivotif is a typhoid vaccine live oral Ty21a authorized by the FDA

References:

Typhoid Fever

Health Information for Travelers to Zimbabwe Traveler View

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Typhoid Vaccine May Offer Extended Protections

Don Hackett — Wed, 27 Feb 2019 21:26:42 +0000

Reviewer: