YF-VAX Yellow Fever Vaccine

Colombia's Yellow Fever Outbreak Threatens Urban Centers

Karen McClorey Hackett — Sat, 19 Apr 2025 10:14:40 +0000

Reviewer:

The ongoing outbreak of Yellow Fever in the Republic of Colombia has been progressively expanding in South America, particularly in regions such as the Amazon basin, the Magdalena River, and departments like Meta.

Furthermore, Yellow Fever (YF) outbreaks have been reported in areas where the disease had not historically occurred, including the municipality of Neira in Caldas, which is situated in the coffee-growing region.

Since September 2024, 75 YF cases and 34 deaths have been confirmed in Colombia, representing a fatality rate of 45%.

In 2025, YF cases are distributed in nine departments: Tolima (59 cases), Putumayo (7), Nariño (2), Caquetá (2), Huila, Vaupés, Cauca, Meta, and Caldas (1).

The total number of confirmed YF-related deaths in Tolima is 23.

"A new case has arrived in the municipality of Chaparral, and here we know we have a focus in the east, south, and north, but we have the solution at our fingertips, and that is vaccination," said Health Secretary Katherine Rengifo Hernández, in a media release on April 15, 2025.

"There are educational checkpoints in place, accompanied by law enforcement, following the directives of our governor."

Although urban transmission of yellow fever has not been reported in Colombia since 1929, there is a potential risk of re-emergence.

Urban areas located below 2,200 meters are at risk of being affected by virus-transmitting mosquitoes. However, with climate change, the range of mosquitoes is expanding.

For example, Bogotá, the Distrito Capital, has approximately 8 million residents and is located at an elevation of just 2,640 meters.

To alert residents and visitors, Columbia's National Government declared a YF public health emergency on April 17, 2025. The measure aims to protect the population's lives, contain the spread of the virus, and mitigate its potential impact on public health.

The Government's urgent call to citizens to get vaccinated against yellow fever was reiterated.

Since September 2024, the National Government has intensified its vaccination strategy. The age range for immunization has been expanded, starting at 9 months of age and including people over 59 years of age, with mass mobilizations in the affected municipalities.

And Health Promotion Entities were instructed to form and operate vaccination teams in coordination with the public and private networks in all affected territories.

According to the U.S. Centers for Disease Control and Prevention (CDC), yellow fever is a viral disease transmitted by the bite of infected mosquitoes. In the first 24 hours, symptoms such as fever, headache, and malaise may manifest. In the following 72 hours, symptoms often intensify with gastrointestinal symptoms such as vomiting, diarrhea, and abdominal pain.

Starting on the fifth day, signs such as jaundice (yellowing of the skin and eyes) and bleeding may appear, which can lead to death in unvaccinated individuals.

To alert the millions of international travelers who visit South America each year, the CDC issued a Level 2 Travel Health Advisory on April 15, 2025, highlighting areas in Bolivia, Brazil, Colombia, and Peru.

The CDC stated that travelers to these areas should get vaccinated at least ten days before traveling abroad.

As of April 19, 2025, the YF-VAX (Stamaril) vaccine is commercially available at travel clinics and pharmacies in the United States. And vaccination certificates, for entry into designated countries, are issued upon completion.

Sub Title:

Yellow Fever vaccination services offered at travel clinics and pharmacies in 2025

References:

Columbia National Government declares a national health emergency due to an increase in yellow fever cases.

YF - Level 2 - Practice Enhanced Precautions

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US CDC Yellow Fever Advisory April 15, 2025

Children May Need More Than One Yellow Fever Vaccination

Karen McClorey Hackett — Thu, 10 Apr 2025 19:54:21 +0000

Reviewer:

Robert Carlson, MD

In 2013, the World Health Organization (WHO) withdrew its recommendation for the yellow fever (YF) vaccine booster doses. However, new research supports the Brazilian National Immunization Program's recommendation for a booster dose of the vaccine at four years of age.

This vaccination policy change is vital for the Federative Republic of Brazil as it combats the spread of this severe mosquito-transmitted virus.

To assess the duration of vaccine-induced immunity, Plos Neglected Tropical Diseases published research on April 9, 2025, of a study cohort involving adults and children in an area in northeastern Brazil without wild-type YF virus circulation, but with a high incidence of other mosquito-transmitted orthoflavivirus, such as Zika.

This phase IV, uncontrolled cohort study was carried out in three municipalities in northeastern Brazil.

The 17DD strain of the (YF-VAX, Stamaril) vaccine was administered to children aged 9 months to 4 years and adults aged 18 to 50 years. Blood samples were collected for antibody titration before vaccination, 30–45 days after vaccination, and one year post-vaccination.

This study showed that YF seroconversion rates 30–45 days after vaccination increased with age, reaching 99% in adults. However, 10% of infants did not have detectable antibodies.

These findings are the first to examine a cohort of vaccinees with serological follow-up in an area without YF viral circulation.

In summary, these researchers wrote, 'Current recommendations assuming lifelong protection from a single dose of the YF vaccine do not appear to provide sufficient protection in high-risk areas, particularly where infants are the primary target for vaccination.'

These findings align with a previous cross-sectional study, which found that 76.4% of children were seropositive between 9 and 23 months after vaccination. In addition to showing lower seroconversion rates, children aged 9–12 months had significantly lower antibody titers over time, with seropositivity dropping below 60% four years after vaccination.

According to the U.S. Centers for Disease Control and Prevention (CDC), yellow fever vaccination is recommended for people aged nine months or older who are traveling to or living in areas at risk for the YF virus, such as Brazil and Colombia.

The 17D yellow fever vaccine was initially approved for human use in 1938, and about 850 million doses have been distributed..

In the United States, the YF-VAX® vaccine is commercially available at travel clinics and pharmacies in April 2025.

Sub Title:

Yellow Fever vaccination services offered in the United States in 2025

Reference:

Immunogenicity of a single dose of the 17DD yellow fever vaccine in a cohort of adults and children

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US CDC 2025

Can Fractional Yellow Fever Vaccinations Decrease Deaths in the Americas

Karen McClorey Hackett — Fri, 21 Feb 2025 10:09:57 +0000

Reviewer:

Robert Carlson, MD

While the Yellow fever vaccine has been found highly effective when administered as a single dose, researchers have continued to examine the minimum dose requirements for seroconversion.

These researchers say the potential advantages of offering fractional doses are increased vaccinations and reduced under-vaccination, which have become a measurable health concern in the Region of the Americas over the past few years.

For example, 61 human cases of yellow fever were confirmed in the Region of the Americas in 2024, of which 30 were fatal (case fatality ratio, 50%).

According to a new study, fractional dosing can protect people similarly to a full dose.

On February 19, 2025, the NEJM published an Orginal Article that concluded that Institut Pasteur de Dakar 17D-204 yellow fever vaccination fractional dose of 500 IU was noninferior to the standard dose of 13,803 IU for producing seroconversion within 28 days.

Noninferiority was shown if the lower boundary of the 95% confidence interval for the difference in the incidence of seroconversion between the fractional dose and the standard dose was higher than -10 percentage points.

Previously, The Lancet Infectious Diseases published an Opinion on April 28, 2023, saying fractional dose yellow vaccination in an emergency or reactive mass vaccination campaign has become essential in stretching the limited vaccine stockpile over a much larger population.

The Lancet also published results from a clinical study in January 2021 (updated Feb. 2022), concluding, 'Fractional doses of all WHO-prequalified yellow fever vaccines were non-inferior to the standard dose in inducing seroconversion 28 days after vaccination, with no major safety concerns. These results support using fractional dosage in the general adult population for outbreak response in a vaccine shortage.'

Moreover, the WHO's initial position on fractional yellow fever vaccine was set out in the 2013 position paper.

According to the Pan American Health Organization (PAHO) rapid risk assessment on February 14, 2025, yellow fever under vaccinations remains a public health concern.

Between 2014 and 2023, yellow fever vaccine coverage declined in about half of the countries with yellow fever endemic areas in the Americas. Six countries had less than 80% coverage: Argentina, Bolivia, Brazil, Panama, Peru, and Venezuela.

This under-vaccination rate is associated with the increase of yellow fever cases in late 2024 and the beginning of 2025 in endemic countries of the Americans, such as Brazil and Columbia.

PAHO says the overall risk of this event in the Americas Region, especially in endemic countries, is classified as ¨High¨ with a ¨High¨ level of confidence based on the available information.

Regardless of the vaccine's dosage, the PAHO and the U.S. Centers for Disease Control and Prevention recommend international travelers be fully protected against the mosquito-transmitted Yellow fever virus before visiting endemic areas in 2025.

In the United States, travel clinics and pharmacies offer the U.S. FDA-approved yellow fever vaccine YF-VAX.

Sub Title:

Yellow Fever Vaccine Fractional Dosage Found Protective

References:

Low-Dose Yellow Fever Vaccine in Adults in Africa

Public Health Risk Assessment related to yellow fever: implications for the Americas Region

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WHO 2025

Arriving at Juan Santamaria International Airport Has Enhanced Requirements

Karen McClorey Hackett — Sat, 08 Feb 2025 11:21:08 +0000

Reviewer:

Robert Carlson, MD

Arriving at the Republic of Costa Rica's Juan Santamaria International Airport (SJO) may include a few arrival requirements for Spring Break 2025. Last year, over 2 million people visited Costa Rica's beaches and mountains, many traveling from the United States.

As of February 8, 2025, the Costa Rican Ministry of Health and the U.S. Embassy in San Jose recently issued travel advisories to inform visitors of some changes.

Beginning in 2025, Costa Rica's Ministry of Health has enforced an expanded yellow fever vaccination requirement for all travelers from designated high-risk countries arriving at SJO. This enhancement is designed to bolster the country's public health defenses against the potential spread of the mosquito-transmitted yellow fever virus.

This yellow fever certificate (ICVP) requirement policy was first implemented in 2007, was enhanced on October 16, 2024, and became effective on January 11, 2025.

According to the Health Ministry, foreigners who arrive in Costa Rica and do not present the ICVP for either YF-VAX or Stamaril vaccination to the SJO immigration authority may not be allowed to enter the Central American country.

Countries now considered at risk and for which yellow fever ICVP is required include, but are not limited to, Bolivia, Brazil, Colombia, Ecuador, Guyana, French Guiana, Paraguay, Peru, Suriname, Venezuela, Trinidad and Tobago, and certain countries in Africa.

Since the YF vaccine is not part of the mandatory Costa Rican vaccination schedule, it must be purchased commercially at pharmacies or travel clinics.

In addition to YF, Costa Rica recommends that visitors protect themselves against the Chikungunya, Dengue, and Zika viruses.

Local chikungunya cases were confirmed throughout 2024 and already in 2025.

To prevent disease, Valneva SE's IXCHIQ® chikungunya vaccine has been approved and is available in numerous countries this year.

Furthermore, the U.S. Embassy recently announced travel incident reports have occurred near the SJO airport.

As of February 5, 2025, the Embassy recommends that visitors use caution when frequenting this area. If confronted on a trip to or from SJO, do not stop; continue progressing forward and contact 911 when it is safe.

Previously, the U.S. State Department issued a Level 2: Exercise Increased Caution Travel Advisory for Costa Rica, which states that visitors should exercise increased caution due to various civil unrest targeting tourists.

The local Embassy says that whether you reside in Costa Rica or are visiting for a week, you should enroll in our Smart Traveler Enrollment Program so that we can better assist you in an emergency.

Sub Title:

Costa Rica recommends yellow fever vaccination in 2025

References:

An amendment to Ministerial Resolution No. DM-CB-3109-2018 of July 20, 2018

Alert: Caution Traveling Near Juan Santamaria International Airport

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Juan Santamaria International Airport 2025

Hajj 1445 Pilgrims Were Well Protected from Disease

Karen McClorey Hackett — Mon, 07 Oct 2024 18:32:31 +0000

Reviewer:

Robert Carlson, MD

The annual Hajj pilgrimage to the Kingdom of Saudi Arabia (KSA) is the largest religious mass gathering in the world. Over the past two decades, up to 3.2 million pilgrims from more than 180 countries have gathered annually in Saudi Arabia for the Hajj.

These pilgrims arrive in Makkah and Madinah from diverse backgrounds, traveling to a confined geographic area, coupled with the close proximity and interactions among them, heightening the potential for spreading infectious diseases and posing unique challenges for public health management and disease control.

In 2024, the Saudi Ministry of Health remained vigilant in monitoring global disease outbreaks and recommend immunizations and preventive measures for the Hajj.

Published by the Journal of Infection and Public Health, Volume 17, Issue 11, November 2024, this review examines current trends in communicable diseases and their impact, drawing insights from expert perspectives on the required (e.g., meningococcal meningitis, polio, and yellow fever) and recommended vaccinations (influenza, COVID-19) for Hajj 1445 participants.

The updated COVID-19 vaccine is mandatory for local pilgrims and strongly recommended for international visitors. Discussions are ongoing on adapting protocols to address emerging variants.

The timing and strain coverage of influenza vaccination, along with quadrivalent meningococcal vaccination, are also emphasized as critical preventive measures.

Diseases such as cholera and yellow fever are addressed, underscoring the need for rigorous surveillance and targeted vaccination strategies to mitigate the risk of transmission during the Hajj.

The continued identification of novel infectious diseases, such as the Middle East Respiratory Syndrome Coronavirus (MERS-CoV), has also prompted modifications to the annual vaccination requirements for the Hajj pilgrimage.

Recently, the WHO Disease Outbreak News confirmed that five MERS-CoV cases, including four deaths, were reported from KSA in 2024.

This review aims to empower pilgrims and healthcare professionals to make informed decisions regarding public health and disease prevention during this significant event by providing up-to-date information on mandated and recommended vaccinations.

The review, posted online on September 30, 2024, provides a comprehensive overview of the vaccinations required and recommended for Hajj pilgrims, taking into account emerging infectious diseases and disease trends.

Seperately, the U.S. CDC publishes its list of recommended and required vaccinations for the 9,500 Americans performing Hajj.

Sub Title:

Mandatory and recommend vaccinations required when visiting the Kingdom of Saudi Arabia

References:

Hajj vaccination strategies: Preparedness for risk mitigation

Hajj Vaccinations 1445

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2024 World Population Review

Vaccine Certificates Can Curtail Yellow Fever Outbreaks

Karen McClorey Hackett — Thu, 26 Sep 2024 18:18:15 +0000

Reviewer:

Robert Carlson, MD

Since 1970, yellow fever has re-emerged as a public health threat in the Region of the Americas, and the risk of yellow fever outbreaks remains high in 2024.

This mosquito-transmitted, acute viral hemorrhagic disease has become endemic in 13 countries in Central and South America.

It is a substantial health risk to about 32 million visitors to South America this year.

On September 19, 2024, the Pan American Health Organization (PAHO) reported five countries in the Americas had confirmed 38 yellow fever cases, 19 of which were fatal.

Peru is the hardest-hit country, with 18 cases and nine deaths confirmed in various departments this year.

These yellow fever cases were all males between 18 and 83 years of age and had a history of exposure to wild and/or wooded areas due to agricultural work activities.

Unfortunately, these men had no yellow fever vaccination records.

Additionally, the PAHO reported that Bolivia, Brazil (3 cases, two deaths), Colombia, and Guyana are the other South American countries reporting cases in 2024.

Although immunization is one of the most successful public health interventions to prevent this disease, most cases reported during 2024 do not have a history of yellow fever vaccination.

Yellow fever has a unique status in the International Health Regulations (2005), which outline requirements for proof of vaccination for people who travel to specific countries or enter some countries from an area where yellow fever is endemic.

To prevent the importation of disease, many countries require proof of vaccination against yellow fever before issuing a visa, mainly if travelers come from or have visited yellow fever-endemic areas.

The U.S. CDC lists South American countries that are endemic to yellow fever.

The PAHO says countries must guarantee vaccination coverage greater than or equal to 95% in the populations of at-risk areas. Health authorities should ensure that they have a strategic reserve inventory that allows them to maintain routine vaccination and, at the same time, respond to possible outbreaks.

In 2023, over 60 million individuals received vaccinations under the WHO's Eliminate Yellow Fever Epidemics strategy.

The U.S. CDC says Sanofi Pasteur's YF-VAX® vaccine is safe and highly effective and is recommended for most travelers aged nine months and older.

Vaccination provides effective immunity within 30 days for 99% of those vaccinated. A single dose can confer sustained immunity and life-long protection without a booster.

"The CDC also recommends that travelers heading to regions experiencing yellow fever outbreaks should consider receiving a booster dose if it has been over ten years since their last vaccination," says Duellyn Pandis, DNP, MS, APRN, FNP-C, Certificate in Travel Health®.

"Certain people should not receive the vaccine, and waivers can be provided," added Pandis, President & CEO of Passport Health-Tampa. "To determine what is best for you, schedule an appointment 4-6 weeks before departure."

YF-Vax is only offered at certified travel vaccine clinics and pharmacies in the U.S.

Note: This news article was updated on Sept. 29, 2024, regarding the U.K. Foreign, Commonwealth & Development Office issuing a 'refrain from visiting Peru' travel advisory regarding health risks.

Sub Title:

Yellow fever vaccination offered at certified travel clinics and pharmacies

Reference:

Yellow fever in the Americas Region -19 September 2024

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PAHO Yellow fever case map Sept. 2024

Yellow Fever Fatalities Reactivate in The Americas

Karen McClorey Hackett — Wed, 27 Mar 2024 17:47:09 +0000

Reviewer:

Robert Carlson, MD

Holly Lutmer PharmD

As international travel rebounds in 2024, the Region of the Americas is expected to receive about 10% more visitors than in 2019. While this is excellent news for the tourism industry, disease outbreaks are also being reported.

In the Americas, there is a high risk of yellow fever outbreaks in 2024.

According to the Pan American Health Organization (PAHO), this mosquito-transmitted viral hemorrhagic disease poses a significant challenge to healthcare professionals. Any delayed recognition of yellow fever's signs and symptoms, which can often be nonspecific and may resemble other acute febrile syndromes, can lead to fatalities.

As of March 19, 2024, there have been seven confirmed cases of yellow fever, including four fatal cases reported in the Region of the Americas this year.

In 2023, four countries in the Region reported 41 confirmed cases of yellow fever, including 23 deaths. These countries include Bolivia (5 cases, including 2 deaths), Brazil (6 cases, including 4 deaths), Colombia (2 cases, including 1 death), and Peru (28 cases, including 16 deaths).

To reduce the 2024 outbreak, the PAHO/WHO reiterated recommendations such as these:

Since the yellow fever vaccine is sufficient to confer lifelong immunity, universal vaccination in children in endemic countries at 12 months of age,
Administered an approved vaccine (Stamaril®) simultaneously with the measles, rubella, and mumps vaccine,
Endemic countries should vaccinate populations in at-risk areas, reaching at least 95% coverage,
Ensure all visitors to endemic areas are vaccinated at least ten days before arrival,
And have a reserve vaccine inventory in case of outbreaks.

Jeri Beales, MSN RN with Destination Health Travel Clinic near Boston, MA, offered these comments to Precision Vaccinations regarding individuals with travel plans who need the yellow fever vaccine: "The data shared by PAHO reminds travelers and health care providers of the serious and often life-threatening risks of traveling to a yellow fever region without appropriate vaccination."

"All but two countries in South America have some risk of yellow fever disease, but no countries require the vaccine for passengers arriving from the United States."

"This leaves many travelers planning an adventure of a lifetime without realizing they will visit a yellow fever region."

"Speak to your provider's office or travel clinic at least several weeks before your planned trip to check if the yellow fever vaccine is needed."

In the January 22, 2024, issue of The Lancet Global Health, Jenny Schnyder and colleagues presented the results of a systematic review and meta-analysis assessing the long-term immunity provided by a single dose of a licensed yellow fever vaccine in people living in areas both endemic and non-endemic for yellow fever.

The authors wrote that in non-endemic areas, a single dose in adults resulted in high seroprotection rates over time (pooled seroprotection rate 94% [95% CI 86–99]), thus providing life-long protection for travelers.

And in endemic areas, adult vaccination resulted in somewhat lower seroprotection rates (76% [65–85]).

However, the studies from endemic areas were all conducted in Brazil and generally used a higher threshold for the definition of seroprotection, which could explain the differences.

However, lower seroprotection rates were found in children (47%) and in people living with HIV (61%), indicating a potential need for booster vaccination in these groups.

To date, there is no indication of waning protection in populations vaccinated in early childhood. But, the YF-VAX® should not be given to individuals who have experienced a severe allergic reaction to eggs, egg products, or any vaccine component.

In the United States, the YF-VAX vaccine is offered at certified clinics and travel pharmacies.

Sub Title:

Yellow fever vaccination required for many travelers in 2024

References:

Epidemiological Update Yellow fever in the Region of the Americas - 21 March 2024

The life-long protective immunity of yellow fever vaccination: time to review?

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Yellow fever case detection South America map 2024

610,000 Individuals Receiving Yellow Fever Vaccine in South Sudan

Karen McClorey Hackett — Wed, 14 Feb 2024 23:24:53 +0000

Reviewer:

Robert Carlson, MD

In response to the yellow fever outbreak in late 2023, the Republic of South Sudan's Ministry of Health announced today that it has initiated a reactive yellow fever vaccination campaign as a preventive response intervention.

As of February 3, 2024, 48 suspected and two confirmed yellow fever cases were reported from Yambio, Nzara, Tambura, Ibba, Ezo, and Maridi Counties of Western Equatoria State.

"To address the (yellow fever) outbreak, a multidisciplinary team of epidemiologists, public health officers, entomologists, laboratory specialists, and risk communication experts conducted an extensive epidemiological investigation to characterize the extent of the outbreak, identify risk/exposure factors, and implement control and prevention measures," stated Honourable Yolanda Awel Deng, Minister of Health in a press release.

Targeting approximately 610 000 individuals aged nine months to 65 years in Yambio, Tambura Ezo, Ibba, and Maridi, the vaccination campaign utilizes doses secured from the Global emergency yellow fever vaccine stockpile of the International Coordination Group on Vaccine Provision.

Dr Humphrey Karamagi, World Health Organization (WHO) Representative for South Sudan, emphasized on February 13, 2024, "The yellow fever vaccination campaign aligns with the global strategy to Eliminate Yellow Fever Epidemics by 2026."

"This reactive measure aims to protect high-risk populations and act as a bridge towards integrating the yellow fever vaccine into routine immunization systems."

About 80 million yellow vaccine doses are produced annually. In the U.S., the YF-VAX® vaccine is licensed and available in 2024.

According to the WHO, yellow fever is a vaccine-preventable acute viral hemorrhagic disease that poses a significant public health threat. Characterized by symptoms such as fever, headache, jaundice, muscle pain, nausea, vomiting, and fatigue, the disease can lead to severe complications, with approximately half of patients succumbing within 7 to 10 days.

As of February 2024, the WHO says about forty-seven countries in Africa and the Americas are either endemic to or have regions endemic to yellow fever. Upon arrival, various countries require visitors to prove they have been vaccinated against yellow fever.

The U.S. recognized South Sudan as a sovereign, independent state on July 9, 2011, following its secession from Sudan.

Currently, the U.S. Department of State says, 'Do not travel to South Sudan due to crime, kidnapping, and armed conflict, as the U.S. government has limited ability to provide emergency consular services to U.S. citizens in South Sudan.'

Sub Title:

Yellow fever disease is vaccine preventable in 2024

Reference:

South Sudan Launches Yellow Fever Vaccination Campaign

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Are Yellow Fever Vaccine Boosters Needed

Donald Hackett — Tue, 06 Feb 2024 16:31:11 +0000

Reviewer:

Robert Carlson, MD

Holly Lutmer PharmD

A recently published review aimed to assess the necessity of a booster vaccination based on the long-term immunogenicity of primary yellow fever vaccination.

Overall, these researchers found that most primary vaccine recipients maintain neutralizing antibodies above protective thresholds ten or more years post-vaccination.

In healthy adults in non-endemic settings, who were primarily travelers, this systematic review and meta-analysis observed high rates of seroprotection 10–60 years post-vaccination (overall seroprotection rate 94%).

Published on January 22, 2024, these findings support the International Health Regulations, stating that single-dose yellow fever vaccination provides lifelong protection for travelers.

However, in people living with HIV and young children, booster doses might still be required because lower grades of protection were found.

Additionally, lower protection rates were observed among residents of endemic areas in Brazil.

Furthermore, because the yellow fever vaccine is contraindicated while using immunosuppressive drugs, no advice is provided by guidelines concerning booster vaccination in this situation.

The complete, unedited study is posted at this The Lancet Global Health link.

Jeri Beales MSN, RN, at Destination Health Travel Clinic, a CDC Yellow Fever vaccination site near Boston, MA., spoke with Precision Vaccinations on February 6, 2024, and stated, "This study adds further evidence that a single dose of yellow fever vaccine provides long-term immunity and backs up the decision in 2016 by the International Health Regulation to recommend a one time dose of yellow fever officially."

"Because yellow fever can sometimes become a deadly illness, it does warrant talking to a travel health specialist before your next trip to endemic areas."

Yellow fever is an acute febrile hemorrhagic and mainly zoonotic disease caused by the yellow fever virus, belonging to the genus Flavivirus, says the U.S. CDC.

Yellow fever is endemic in sub-Saharan Africa and South American tropical regions, where outbreaks have been reported, such as in Brazil.

Various countries in these regions require proof of vaccination before arrival.

As of February 6, 2024, the YF-VAX® vaccine is offered in the United States at certified clinics and pharmacies. The U.S. CDC says a yellow fever vaccine booster dose is unnecessary.

Other countries offer various yellow fever vaccines.

Sub Title:

Yellow fever vaccination are required by certain countries in 2024

Reference:

Long-term immunity following yellow fever vaccination: a systematic review and meta-analysis

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Will Yellow Fever Outbreaks Migrate North

Donald Hackett — Mon, 16 Oct 2023 21:08:38 +0000

Reviewer:

Robert Carlson, MD

Holly Lutmer PharmD

Tasked with coordinating United States readiness for its next significant global infection threat, the White House Office of Pandemic Preparedness and Response will emphasize emerging coronavirus infections, zoonotic influenzas, and infections caused by filoviruses and pathogens.

But mosquito-transmitted virus (arbovirus) infections are equally important, and their spread has begun accelerating in the American South, wrote Peter J. Hotez, M.D., Ph.D., and Angelle Desiree LaBeaud, M.D., in a Perspective published by the New England Journal of Medicine on October 14, 2023.

Excerpts from this travel-vaccine related editorial are inserted below.

Over the past decade, Florida and Texas have experienced autochthonous outbreaks, each transmitted by Aedes mosquitoes, primarily Aedes aegypti and Ae. albopictus.

Data generated from epidemiologic, mapping, and modeling analyses reveal a new confluence of climate change, urbanization, and shifting patterns of human migrations that predicts significant upticks in infections with viruses transmitted by Aedes mosquitoes.

Some forecasts are, therefore, bleak, suggesting that much of the southeastern U.S. will become widely suitable for dengue or yellow fever.

In 2022, confirmed cases of yellow fever were reported in three countries in the Region of the Americas: Bolivia (5), Brazil (5 cases, including four deaths), and Peru (7 cases, including five deaths).

Yellow fever, in particular, has a concerning legacy.

During the 1800s, yellow fever caused highly lethal and economically devastating urban epidemics in southern U.S. coastal cities and those on the Mississippi River.

It was sometimes known as "yellow jack," from the name of a nautical flag hoisted from ships arriving from the Caribbean that were quarantined because of suspected disease cases.

Yellow fever's most feared complication was vomito negro (black vomit), occurring in the end stages of lethal illness owing to hemorrhagic bleeding in the upper gastrointestinal tract.

Yellow fever outbreaks decimated southern U.S. cities for nearly 100 years, beginning in 1820. In their 2005 book Yellow Jack, J.R. Pierce and J. Writer noted, "There is not a single disease today that can terrorize a community the way yellow fever did.… Americans living in seaport cities came to dread the approaching summer. This seasonal anxiety lasted over a hundred years."

The last major U.S. yellow fever epidemic occurred in New Orleans in 1905 (with an estimated 5,000 cases and 1,000 deaths). But there are renewed fears that yellow fever could return to Gulf Coast cities, such as Galveston, Corpus Christi, and Houston, Texas; Mobile, Alabama; New Orleans; and Tampa.

Such an epidemic could take a more significant toll than most modern infectious disease outbreaks in the United States.

An effective, albeit expensive, yellow fever vaccine exists today, but it's a live-virus vaccine and can have serious, if rare, side effects.

Sanofi Pasteur's YF-VAX® vaccine is U.S. Food and Drug Administration-approved.

Currently, the U.S. population is nearly entirely unvaccinated against yellow fever, and there are no vaccine doses in the U.S. Strategic Stockpile, stated these doctors.

During a sizable epidemic, yellow fever could tear quickly through unimmunized populations across the American South, and it is unlikely that the U.S. government would be prepared to acquire and distribute vaccines promptly.

In Brazil, fractional dosing of yellow fever vaccines has been used to extend vaccine inventories and quickly amplify herd immunity, a strategy approved by the World Health Organization (WHO) for emergencies.

Ultimately, we need a comprehensive plan for better-coordinating mosquito surveillance and control among counties at risk.

We believe yellow fever should be prioritized as part of our national pandemic-preparedness efforts, given that the conditions are now in place for yellow jack to return and sicken many people in southern U.S. cities, wrote these health experts.

The full unedited article is posted at this link.

According to the WHO, the risk of acquiring yellow fever during travel is difficult to predict.

For a 2-week stay, the estimated risk for illness and death due to yellow fever for an unvaccinated traveler visiting an endemic area are as follows: for West Africa, the risk for illness is 50 per 100,000, and the risk for death is 10 per 100,000; for South America, the risk for illness is 5 per 100,000 and risk for death is 1 per 100,000.

As of October 16, 2023, both dengue and yellow fever vaccines are available at travel vaccination clinics and pharmacies.

Sub Title:

Yellow fever vaccine is approved in 2023

References:

Yellow Jack’s Potential Return to the American South

PAHO Yellow Fever Documents 2023

US CDC Yellow Book - Yellow Fever 2024

Yellow fever outbreaks 2023

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Monday, October 16, 2023 - 22:45

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PAHO yellow fever case map 2023

Vaccination Cards Still Required by Some Counties

Donald Hackett — Fri, 06 Oct 2023 08:49:27 +0000

Reviewer:

Robert Carlson, MD

Now that the U.S. federal government is not distributing COVID-19 vaccines, the Centers for Disease Control and Prevention (CDC) has discontinued issuing new proof of vaccination cards, reported the AP on October 4, 2023.

The federal government shipped more than 980 million vaccination cards between late 2020 through early May 2023, according to the latest available data from the CDC.

Previously, the CDC posted a notice of End to Requirement for air passengers to provide proof of COVID-19 Vaccination before visiting the U.S. in May 2023.

However, the European community is prepared to continue verifying a person's vaccination status. The E.U. Digital COVID certificate was issued to more than 2.3 billion people across 51 countries.

The WHO Global Digital Health Certification Network (GDHCN) became effective in Europe on July 1, 2023, and has integrated the E.U. certificate into the GDHCN.

The GDHCN's digital capabilities may include verification of vaccinations and prescriptions across borders, the International Patient Summary, verification of vaccination certificates within and across borders, and certification of public health professionals through the WHO Academy.

The U.S. State Department recently launched the Bureau of Global Health Security and Diplomacy.

The Bureau's overarching mission is to fortify the global health security architecture to effectively prevent, detect, control, and respond to infectious diseases.

By leveraging and coordinating U.S. foreign assistance, the Bureau aims to foster robust international cooperation, enhancing protection for the U.S. and the global community against health threats through strengthened systems and policies, wrote U.S. Secretary of State Anthony J. Blinken on August 1, 2023.

Historically, some countries utilized the International Certificate of Vaccination or Prophylaxis (ICVP), known as the yellow card, to confirm yellow fever and polio vaccinations.

As of 2022, the WHO published an updated Country List to identify which countries require an ICVP to enter.

Sub Title:

Yellow fever vaccination card required by thirty countries

References:

Goodbye to the COVID-19 vaccination card

CDC Vaccine Administration Management System

US Bureau of Global Health Security and Diplomacy

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Google News Keywords:

vaccines, vaccinations

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Saturday, October 7, 2023 - 06:45

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TSA airport screening 2023

Africa Commits Catch-Up Vaccinations for Children

Karen McClorey Hackett — Mon, 27 Feb 2023 16:58:10 +0000

Reviewer:

Holly Lutmer PharmD

Robert Carlson, MD

African heads of state recently agreed on key measures to revamp routine immunization across the continent following massive disruptions by the pandemic that stymied childhood vaccination programs.

These vaccination disruptions heightened outbreaks of vaccine-preventable diseases.

Currently, vaccine-preventable disease outbreaks are ongoing in 31 African countries, with 17 having more than one vaccine-preventable disease outbreak.

For example, the median vaccination coverage for measles was 69% across the African continent in 2021.

And outbreaks of yellow fever, cholera, and polio are common.

A total of 8.4 million children in the African region were left out of immunization services in 2021, according to estimates by UNICEF and World Health Organization (WHO).

At a high-level event on the sidelines of the 36th Ordinary Session of the African Union (AU) Heads of State and Government in Addis Ababa, the leaders endorsed a declaration on “Building momentum for routine immunization recovery in Africa."

This effort aims to “revitalize the momentum for all populations to have universal access to immunization to reduce mortality, morbidity, and disability, and consequently help Member States to achieve their goals.”

“Progress in meeting immunization targets, we believe, is a driver for equitable health outcomes for children, mothers, and the population as a whole,” said H.E. Dr. Julius Maada Bio, President of Sierra Leone, in a press release on February 19, 2023.

“We believe as a government that the returns on investment for immunization are very high for our progress towards meeting the SDGs.”

In Africa, vaccine-preventable diseases are responsible for 93% of ongoing infectious disease outbreaks.

The “Building momentum for routine immunization recovery in Africa” declaration also aims to reignite the continent’s commitment to meet the goals of the Immunization Agenda 2030, a new global strategy to address the challenges of immunization and save more than 50 million lives worldwide.

The declaration called on African regional economic communities, health organizations, and the African Development Bank to support the initiative.

It also urged vaccine manufacturers to improve access to doses and the UNICEF and WHO to support countries to monitor progress towards the immunization goals.

As of February 27, 2023, the U.S. CDC has issued various travel alerts regarding disease outbreaks in Africa.

Sub Title:

Yellow fever, measles, polio under vaccinated African children

Reference:

African leaders call for urgent vaccination action 2023

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Age Groups:

Childhood

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Africa

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Wednesday, March 1, 2023 - 06:30

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WHO Africa Feb. 2023

Spring Travelers May Break Airport Screening Record

Karen McClorey Hackett — Mon, 20 Feb 2023 20:45:05 +0000

Reviewer:

Robert Carlson, MD

Holly Lutmer PharmD

The Transportation Security Administration (TSA) recently confirmed it is prepared for the increase in air travelers and offers a few travel tips for the most efficient checkpoint experience this spring.

TSA anticipates that its Transportation Security Officers (TSOs) will screen increasing numbers of passengers at airport checkpoints as travel volumes may exceed pre-pandemic levels.

As of February 19, 2023, the TSA reported security checkpoint activity is on par with pre-pandemic 2019.

The spring break travel season begins around mid-February and continues through late April.

"We fully expect to see an upward trend in travel volumes throughout 2023, including during the spring break period," said TSA Administrator David Pekoske in a related press release.

"We coordinate closely with airports and air carriers to prepare for the projected increase in travel volumes.

"We expect to meet our wait time standards of 30 minutes or less in standard lanes and 10 minutes or less in TSA PreCheck® lanes."

"However, there may be some situations where the capacity of a checkpoint is exceeded."

In January 2023, 92% of TSA PreCheck passengers waited less than five minutes at TSA checkpoints nationwide.

The TSA published its top six travel tips to help spring break travelers arrive prepared for the most efficient TSA checkpoint experience:

Tip 1: Pack smart – start with an empty bag and ensure you do not have any prohibited items.

Tip 2: Remember the 3-1-1 Liquids Rule. Passengers may bring a quart-sized bag of liquids, aerosols, gels, creams, and pastes through the checkpoint if each item is 3.4 ounces or less. And FAA regulations prohibit travelers from consuming alcohol on an aircraft unless a flight attendant serves. Additionally, flight attendants are not permitted to serve a passenger who appears to be intoxicated.

Tip 3: Enroll in TSA PreCheck. The five-year enrollment fee is $78; online renewals are $70. So don't delay, enroll in TSA PreCheck today.

Tip 4: Ask TSA before you travel. Contact TSA's travel security experts over social media by sending a message to @AskTSA on Twitter. Passengers may also text 275-872 ("AskTSA") on any mobile device.

Tip 5: Arrive early and carry on kindly. Spring break travelers should give themselves plenty of time to account for traffic, parking, rental car returns, airline check-in, security, and making any airport purchases before boarding a flight.

Tip 6: Be checkpoint ready. Arrive at the checkpoint lane with a mobile or printed boarding pass and valid ID readily available.

And those traveling abroad for spring break should check the U.S. Customs and Border Protection Know Before You Go page to learn about required documentation.

For more information about TSA screening procedures, visit the customer service page, read the frequently asked questions, or watch TSA's travel tips videos.

Also, the U.S. Centers for Disease Control and Prevention publishes country-specific vaccination suggestions.

These travel vaccines may require ten or more days to build up immunities that some countries require, such as Brazil and yellow fever.

Travel vaccines are offered in the U.S. at certified clinics and pharmacies.

Sub Title:

TSA is prepared for spring break 2023 travelers

References:

U.S. TSA news Feb. 15, 2023

TSA passenger screening Feb 2023

Foreign Consular Offices in the U.S. visit the U.S. Department of State website.

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travel vaccine

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Monday, February 27, 2023 - 12:45

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by Dominique P.

Yellow Fever Less Risky in Certain African Countries

Donald Hackett — Thu, 05 Jan 2023 16:44:24 +0000

Reviewer:

Robert Carlson, MD

Holly Lutmer PharmD

The World Health Organization (WHO) African Region recently published some good and less than positive news regarding yellow fever.

On January 3, 2022, the WHO African Region published updated data that indicates the number of new yellow fever cases has steadily decreased.

From January 2021 to early December 2022, a total of 203 confirmed and 252 probable cases with 40 deaths (Case Fatality Ratio 9%) were reported, with a decline in new case reports throughout this period.

However, the data also indicates a significant population remains unprotected from this potentially severe disease.

According to the WHO/UNICEF Estimates of National Immunization Coverage, routine immunization coverage against yellow fever in the African Region for childhood vaccinations was 48% in 2021.

Over 4.3 million persons were recently vaccinated to address this shortcoming in Cameroon, the Central African Republic, Chad, Ghana, and Kenya.

These vaccinations may have contributed to the downward trend in new cases in late 2022, says the WHO.

However, there remains persistent yellow fever virus circulation in certain countries.

Recent confirmations have been from locations with little or no underlying yellow fever immunity, such as near the urban areas in Cameroon and Uganda.

In summary, the WHO says the overall global risk remains low, as no yellow fever cases related to the current outbreak have been reported outside the African region.

But, the WHO Eastern Mediterranean Region may be at risk.

To notify international travelers of their potential health risks, the U.S. Centers for Disease Control and Prevention (CDC) issued various travel alerts in 2022, such as in Kenya.

Yellow fever is an acute viral hemorrhagic fever that is spread through the bites of infected mosquitoes, says the CDC. Symptoms of yellow fever (fever, chills, headache, backache, and muscle aches) develop 3-6 days after infection.

About 12% of people infected with the yellow fever virus develop severe illnesses that can lead to liver disease, bleeding, shock, organ failure, jaundice, and sometimes death.

Yellow fever is prevented by an effective vaccine, which is safe and affordable.

A single dose of a yellow fever vaccine (YF-Vax® or Stamaril®) is sufficient to grant sustained immunity and life-long protection against yellow fever disease.

The vaccine provides effective immunity within 30 days for more than 99% of people vaccinated.

In the U.S., the YF-Vax yellow fever vaccine is available at certified travel clinics and pharmacies.

Additional yellow fever outbreak news is posted at Vax-Before-Travel.com.

Sub Title:

WHO Africa yellow fever vaccination rates improve

References:

WHO Africa Yellow Fever update

U.S. CDC Travel Alerts

CDC Yellow Fever

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Google News Keywords:

yellow fever, YFVax, Stamaril, vaccines

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Fact checked:

Friday, January 6, 2023 - 11:45

Image Caption:

WHO Africa yellow fever cases 2022

TSA Tips For Travelers With Disabilities

Karen McClorey Hackett — Fri, 23 Dec 2022 16:23:04 +0000

Reviewer:

Robert Carlson, MD

When departing from Texas on a winter holiday, air travelers with disabilities or medical conditions and who use medical devices should not think of a Transportation Security Administration (TSA) checkpoint as a barrier to their vacation.

While all travelers must undergo screening at the Austin-Bergstrom International Airport TSA checkpoint, passengers and companions may consult a TSA officer about the best way to relieve any concerns during the screening process.

Individuals may provide an officer with a TSA notification card or other medical documentation to describe the condition discretely.

Travelers also may request accommodations to the security screening process.

Furthermore, if a passenger with a medical device, medical condition, or disability is approved to use TSA Pre✓®, the person has options during the screening process.

The TSA has resources for travelers with disabilities or individuals who travel with medical devices or medical conditions to ensure they can get through the security screening process successfully, respectfully, and efficiently.

These resources include the TSA Cares helpline, the TSA Contact Center, Passenger Support Specialists, information posted on the TSA website, and an interactive Twitter account.

The TSA's helpline, called TSA Cares, enables travelers or families of passengers with disabilities and medical conditions to call 1-855-787-2227 with questions about screening policies and procedures.

And Passenger Support Specialists are highly trained TSA officers at airports who have special training in successfully engaging with and screening individuals with disabilities or medical conditions or who travel with medical devices.

Travelers requiring accommodations to the screening process or concerned about the security screening process at the airport may ask for a Passenger Support Specialist or a Supervisory TSA Officer who can provide on-the-spot assistance.

These TSA resources may be needed as the holiday travel season ramps up.

The TSA's recent screening data as of December 22, 2022, indicates air travel volume is approaching levels last seen in 2019.

Additionally, when visiting certain countries, the U.S. Centers for Disease Control and Prevention (CDC) suggest speaking with a certified travel vaccine advisor about one month before departure.

The CDC has identified continues that require proof of yellow fever, polio, and measles vaccinations.

These travel; vaccines are offered at various clinics and pharmacies throughout the U.S.

Vax-Before-Travel publishes fact-checked, research-based travel vaccine information manually curated for mobile readers.

Sub Title:

Austin Texas Airport supports flyers with disabilities or medical conditions

References:

TSA airport screening data

TSA shares tips for Austin-Bergstrom International Airport

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Google News Keywords:

TSA, airport, screening

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Fact checked:

Saturday, December 24, 2022 - 07:15

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TSA screening