Sao Paulo

Zika Seroprevalence of 2.4% in Postpartum Women

Karen McClorey Hackett — Sat, 24 May 2025 10:31:44 +0000

Reviewer:

Over the past decade, the Zika virus has been found in over 50 countries and territories in the Region of the Americas.

As of May 24, 2025, Zika virus (ZIKV) remains a significant public health concern in Brazil, with over 11,500 cases reported this year.

While most people recover from this mosquito-transmitted disease, pregnant women and their unborn children may become infected, leading to serious health issues.

Researchers have stated that understanding population serological status, particularly in pregnant women, is vital for estimating the spread of this virus.

A research article published by the Journal of Medical Virology on May 21, 2025, assessed ZIKV seroprevalence in pregnant women and the transplacental transfer of antibodies to their newborns, crucial for early-life protection.

Effective transplacental transfer of specific ZIKV antibodies from mothers to newborns was observed.

A cross-sectional seroprevalence study was conducted with 601 postpartum women and their newborns in São Paulo city, Brazil, post-ZIKV fever outbreak.

Paired maternal and umbilical blood samples were collected for ZIKV antibody testing. ZIKV neutralizing antibodies (nAbs) were detected in 2.4% of these women.

Maternal and neonatal characteristics were associated with seropositivity for ZIKV and the antibody transfer to neonates. Maternal place of birth, parity, education level, and prenatal Toxoplasmosis serology were identified as risk factors associated with ZIKV infection.

Low seroprevalence of ZIKV antibodies in the study population indicates a high vulnerability to infection by these viruses.

The low ZIKV seroprevalence observed in this study contrasts sharply with higher rates reported in the Northeast of Brazil, with 63% in pregnant women in Salvador (2015–2016) and 30% among Bolivian blood donors (2016–2017).

This study's findings offer a comprehensive understanding of the antibody transfer dynamics in the context of ZIKV infection. This understanding is paramount, as it can potentially inform vaccine development strategies in endemic regions and guide the development of more effective neonatal infection prevention measures.

Published in JAMA Network Open in January 2025, a population-based study of mortality rates among 11.4 million children born with a severe Zika virus infection had a strikingly higher risk of overall and cause-specific mortality.

Young children with congenital Zika syndrome (CZS) had a 13-fold higher risk of death compared with those without CZS. This study found that the cause-specific mortality hazard ratio was 30.28.

The U.S. CDC's updated Yellow Book says healthcare professionals should know how to diagnose, treat, and prevent Zika in international travelers, especially pregnant women.

The CDC writes providers should 'carefully evaluate pregnant women with laboratory evidence of Zika virus infection; closely manage these patients during pregnancy and carefully evaluate live-born infants for clinical features associated with intrauterine infection.'

While an innovative Zika vaccine candidate is conducting clinical trials in 2025, no vaccine has been approved.

Researchers recently estimated that mosquitoes are carrying the Zika virus into new regions, and approximately 1.3 billion people could be affected by Zika by the year 2050.

The Pan American Health Organization writes, 'The decision to travel to a country with a history of Zika circulation should be based on a personal risk assessment, done in conjunction with the traveler's healthcare provider, that accounts for individual risk factors for severe outcomes from the possibility of a Zika infection.'

Sub Title:

Zika infection rates in women and infants vary by geography

Reference:

Seroprevalence and Placental Transfer of Zika and Dengue Virus Antibodies in Postpartum Women in Southeast Brazil

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Brazil's Dengue Outbreak Moves South

Karen McClorey Hackett — Wed, 02 Apr 2025 10:40:27 +0000

Reviewer:

Robert Carlson, MD

For decades, the Federative Republic of Brazil has been one of the most affected countries by dengue outbreaks in the world, with an average of over three million confirmed cases most years.

Over the past 25 years, nearly 18 million Brazilians have been infected with this mosquito-transmitted virus.

However, Brazil was the unfortunate leader in the Region of the Americas last year, reporting over 9.6 million dengue cases and 5,441 related deaths in 2024. Many of those cases were confirmed in São Paulo.

According to a commentary published by The Lancet on March 22, 2025, this 'situation poses a concern about whether the epidemic will be recurrent or decline as more people get infected and develop lifelong immunity.'

There are four dengue viruses, which means people can be infected multiple times.

A study published in 2024 concluded that the co-circulation of multiple dengue virus genotypes is associated with increased cases, highlighting the importance of continuous surveillance.

There is a concern about whether the current range of dengue across the territory will be rescinded, maintained, or expanded. The latter appears to be the present situation, with particular concern for the South region.

These researchers created risk maps for potential outbreaks using Brazil's historic dengue incidence rate to answer this.

'First, we summarized the dengue incidence for each municipality over the past ten years. We aggregated the confirmed dengue cases from 2015 to 2024 and calculated the cases-to-population ratio, representing the historical incidence.

To create a more accurate version of this ratio, we applied a Bayesian model that considers the case counts from neighboring areas to estimate the actual number of cases within each municipality.

For the short-term period, we assumed that the ratio reflects lifelong immunity and that it is unlikely for a dengue season to include serotypes that were not represented in our dataset. Then, the complement of the ratio was calculated to determine the outbreak risk.

'This means that areas (in the south and mountains) with low dengue incidence over the past ten years are likely to be more susceptible to dengue outbreaks,' wrote these researchers.

Mosquitoes that spread Dengue viruses usually live below 6,500 feet elevation; therefore, a person's chances of getting dengue in high altitudes are very low.

To notify international travelers, the U.S. Centers for Disease Control and Prevention (CDC) published a Health Update on March 18, 2025, highlighting the ongoing risk of dengue infections and updates to testing recommendations.

On March 20, 2025, the CDC reissued a Global Travel Health Notice regarding dengue outbreaks in the Americas, which highlighted Brazil.

While about 40 countries offer dengue prevention vaccines in 2025, the U.S. does not.

Sub Title:

Dengue is a vaccine preventable disease in April 2025

Reference:

On the verge: outbreak risk after two years of record-breaking dengue epidemics in Brazil

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The Lancet March 22, 2025

Brazil's Dengue Vaccine Production to Reach 100 Million

Karen McClorey Hackett — Thu, 20 Feb 2025 14:59:43 +0000

Reviewer:

Robert Carlson, MD

The government of São Paulo, Brazil, through the State Department of Health, recently declared a state of public health emergency 'in view of dengue becoming epidemic.'

This agency says the 'cause of concern is the reappearance of the mosquito-transmitted dengue serotype 3 after seventeen years without circulation, as the Sao Pailo State population is not immune to this specific dengue strain.'

As of February 19, 2025, the emergency measure was adopted after the state of São Paulo reported 280 cases of dengue fever per 100,000 inhabitants in 2025, near the threshold for a state of emergency. State Secretary of Health Eleuses Paiva signed the state of emergency decree.

Data from the State Department of Health indicate more than 124,000 cases and 113 deaths throughout the state in 2025 alone, with 225 cities reporting more than 300 cases per 1,000 inhabitants, some of them in the northwest region.

Eleuses pointed out a series of measures to combat dengue fever in the state, including the vaccine developed by the Butantan Institute, which the National Health Surveillance Agency approves.

According to Secretary Paiva, the country will only be able to rid itself of the dengue epidemic that emerges yearly with large-scale vaccinations.

"We are providing the Butantan Institute with all the necessary infrastructure to ensure that we can produce the vaccine properly, as we are again experiencing a dengue epidemic. There is only one way to end dengue in our country, and that is to be able to put the vaccine in the arms of all Brazilians. In this sense, we have the full commitment of Butantan, the government, and the secretariat to focus on this," said Eleuses in a media release.

The director of the Butantan Institute, Esper Kallás, stated that the Institute made a Butantan-DV vaccine registration request on December 16, 2024. Butantan-DV is the only single-dose vaccine capable of neutralizing the four dengue serotypes.

"We ....intend to have the entire package sent back to Anvisa for consideration in the coming weeks," Kallás added.

"In 2025, we are working on the final stages of adjusting the processes and producing the initial batches, with the expectation of delivering 1 million doses, which would represent 1 million vaccinated people (in 2025)."

"In 2026, we would scale up and deliver another 60 million doses, and in 2027, another 40 million doses, to achieve the 100 million vaccination curve for the Brazilian population," explained Esper Kallás.

As of February 2025, the single-dose, tetravalent, live-attenuated Butantan-DV Dengue Vaccine is conducting phase 3 clinical trials. The vaccine results from a partnership between Butantan, the U.S. National Institutes of Health, and the American Type Culture Archive. Development of the tetravalent dengue vaccine began at Butantan Institute in 2010.

In addition to Brazil's needs, dengue vaccines are needed throughout the Region of the Americas, which set all-time case and fatality records in 2024.

For example, Florida's southeast coast has reported locally-acquired dengue cases in the United States for the past few years.

On January 20, 2025, the World Health Organization classified dengue as a grade 3 emergency, with an estimated 4 billion people at risk globally.

When visiting a dengue outbreak area in 2025, the U.S. CDC suggests discussing disease prevention options with a travel vaccine expert. As of February 20, 2025, no dengue vaccines are offered in the U.S.

Sub Title:

Sao Paulo Brazil declares public health emergency in 2025

Reference:

São Paulo government declares state of emergency for dengue fever

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by Peggy Lachmann-Anke

Mosquitoes Can Carry Three Alphaviruses Simultaneously

Karen McClorey Hackett — Sat, 15 Feb 2025 13:34:45 +0000

Reviewer:

Robert Carlson, MD

There is increasing evidence people have been co-infected with various combinations of mosquito-transmitted diseases. When this occurs, diagnosing which disease is causing impacting a person becomes challenging.

For example, during 2024 and early 2025, outbreaks of chikungunya, dengue, and Zika viruses were reported in multiple countries in the Region of the Americas, such as Brazil.

A new study (Volume 20, June 2025, 100991) posted on February 10, 2025, shows that Aedes aegypti mosquitoes can carry three alphaviruses simultaneously.

These researchers wrote, 'While observations of multiple infections in the same patient indicate Ae. aegypti may be exposed to two viruses simultaneously; it is unclear if such infections result from a single bite from a coinfected mosquito or the result of sequential bites of single-infected mosquitoes.

This study aimed to determine if Ae. aegypti can concurrently transmit chikungunya (CHIKV), Mayaro, and Una viruses. It will also explore if coinfections with these alphaviruses affect the transmission of each virus.

Our results, contrary to our hypothesis, show that coinfection with two viruses does not influence the transmission potential of Ae. aegypti for either virus.

The viral load, however, is decreased in mosquitoes with triple infections compared to the other treatments.

In addition, we show that Ae. aegypti can transmit two alphaviruses simultaneously, having detected a UNAV- and MAYV-positive saliva sample and a UNAV- and CHIKV-positive saliva sample containing an infectious virus.

In conclusion, understanding how coinfections affect the biology and transmission of arboviruses is essential for assessing public health risks. Beyond the risk of arboviruses spilling from wildlife to humans, there is the often-overlooked risk of spillback (or reverse zoonosis), where viruses move from humans to wildlife, potentially establishing permanent sylvatic reservoirs. This is seen with the yellow fever virus, which after being introduced to the Americas alongside Ae. aegypti, transitioned from urban outbreaks to a sylvatic cycle involving non-human primates.

This study's findings further illustrate that emerging Ae. aegypti-vectored arboviruses in the Americas are a public health concern and a broader One Health challenge.

Of these diseases, an approved chikungunya vaccine (IXCHIQ®) has been approved since 2023 and is generally available at travel clinics and pharmacies in Europe, the U.K., and the United States in 2025.

Sub Title:

Chikungunya Virus Coinfections Transmitted by Infected Mosquitoes

Reference:

Effect of chikungunya, Mayaro and Una virus coinfection on vector competence of Aedes aegypti mosquitoes

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One Health Volume 20, June 2025, 100991

Yellow Fever Vaccine Boosters Suggested When Visiting Sao Paulo

Karen McClorey Hackett — Mon, 03 Feb 2025 16:27:45 +0000

Reviewer:

Robert Carlson, MD

The Ministry of Health of the Federative Republic of Brazil recently warned international travelers about an increase in the transmission of the yellow fever virus, which is expected to continue until May 2025.

As of February 2, 2025, this yellow fever (YF) warning is particularly relevant for the Brazilian states of São Paulo, Minas Gerais, Roraima, and Tocantins.

This travel alert is essential for São Paulo, which welcomed over 2.2 million tourists last year and may account for most of Brazil's yellow fever cases in 2025.

The São Paulo State Health Department is investigating suspected and confirmed yellow fever outbreaks in the city of Ribeirão Preto.

The Health Ministry wrote, 'People planning to travel to areas where yellow fever is transmitted or to rural and forested regions should check their vaccination records."

"Those who have not yet been vaccinated or received a fractional dose in 2018 should seek out a health unit at least ten days before traveling to get immunized and avoid exposure to the virus without protection.'

To combat future yellow fever cases and fatalities, Brazil's Ministry of Health has decided to increase the distribution of the yellow fever vaccine (Stamaril) in 2025. Sao Paulo state will receive two million doses, with an additional 800,000 doses by the beginning of February.

In 2024, the Ministry of Health distributed 20,882,790 vaccine doses throughout Brazil.

Last year, the Pan American Health Organization confirmed over 50 yellow fever cases, including 24 deaths, in the Region of the Americas.

In 2017, the U.S. CDC expanded its vaccination (YF-Vax) recommendations for travelers to Brazil in response to a large YF outbreak in the country's eastern states.

In 2025, the CDC says travelers older than 9 months going to the state of São Paulo, including the city of São Paulo and all coastal islands, consider vaccination.

"If traveling from the U.S. to Brazil, Yellow Fever is not required for entry. However, if you visit other countries after leaving Brazil, the vaccine may be required for entry," Duellyn Pandis, DNP, APRN, FNP-C, informed Vax-Before-Travel News.

"The YF vaccine is considered a lifetime vaccine, but the CDC and other health ministries encourage a booster after 10 years if traveling to an area with high YF activity, such as São Paulo."

"It's recommended to get vaccinated before you travel to an endemic country region country requirements,' added Pandis, President of Passport Health-Tampa.

The CDC also recommends that visitors to Brazil speak with a travel vaccine expert about chikungunya and typhoid vaccination options, especially those staying with friends or relatives or visiting smaller cities or rural areas. Furthermore, several regions in Brazil are reporting cases of Oropouche.

Sub Title:

Yellow fever travel alert Issued for São Paulo, Minas Gerais, Roraima and Tocantins

References:

Brazil technical note - Yellow fever 2025

Brazil Ministry of Health issues alert for increase in yellow fever

US CDC 2025

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Brazil Ministry of Health Feb. 2, 2025

Severe Zika Infection Causes 13-fold Greater Mortality Risk in Children

Karen McClorey Hackett — Fri, 24 Jan 2025 19:13:47 +0000

Reviewer:

Robert Carlson, MD

Last year, the Region of the Americas reported over 42,127 Zika virus (ZIKV) cases, many including children. Some of these young Zika patients died from severe infections in their mother's wombs or immediately after birth.

The findings of a new Original Investigation conducted in May 2024 should empower insights that develop protocols to prevent early mortality and improve child survival during Zika outbreaks.

Published in JAMA Network Open on January 23, 2025, this population-based study of mortality rates among 11.4 million children born with a severe Zika virus infection had a strikingly higher risk of overall and cause-specific mortality.

Young children with congenital Zika syndrome (CZS) had a 13-fold higher risk of death compared with those without CZS.

This study found the cause-specific mortality hazard ratio was 30.28.

Of 3,080 children notified as CZS cases, 444 (14.4%) died, including 154 (34.7%) from respiratory diseases, 152 (34.2%) from infectious and parasitic diseases, and 82 (18.5%) from nervous system diseases.

These researchers wrote, 'In children with CZS, dysphagia may favor the premature escape of the bolus into the pharynx, increasing the risk of death due to airway obstruction and the acquisition of respiratory infections caused by bronchoaspiration.'

'This could potentially explain the high respiratory system mortality risk. Furthermore, other factors in children with CZS, such as phrenic nerve palsy with diaphragmatic paralysis22 and seizures, can increase the risk of pulmonary aspiration, leading to respiratory failure.'

A separate study published in Pediatrics in January 2025 concluded children exposed to ZIKV in utero, even without CZS, demonstrate a greater risk for neurodevelopmental delay in early childhood, with the timing of maternal infection being a significant predictive risk factor.

Additionally, the International Journal of Infectious Diseases published a study in 2025 showing that children with CZS will have more frequent hospitalizations in early childhood. Scientists have reported that ZIKV RNA is detectable in the semen of infected men for months and is found in newborn children.

Previous research focused on the 2015–2016 ZIKV outbreak in the Region of the Americas revealed the ability of ZIKV from the Asian lineage to cause birth defects of the brain and eyes, including severe microcephaly.

In the United States, the U.S. CDC reported 19 non-congenital Zika cases in the U.S. (1 imported case in Texas) last year. In 2023, the CDC reported five non-congenital cases in U.S. residents and 27 in U.S. territories.

The CDC says Zika-spreading mosquitoes are found throughout Puerto Rico.

Currently, the best way to avoid contracting ZIKV is to avoid being bitten by a virus-carrying mosquito.

As of January 24, 2025, no approved Zika vaccines exist, but vaccine candidates are currently conducting clinical research.

Note: This article's picture was updated on Jan. 29, 2025.

Sub Title:

Zika vaccine Development continues in 2025

Reference:

All-Cause and Cause-Specific Mortality in Children With Congenital Zika Syndrome in Brazil

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Brazil's Extensive Chikungunya Outbreak Impacted by Virus Genotype Adaptation

Karen McClorey Hackett — Fri, 27 Dec 2024 17:30:12 +0000

Reviewer:

Robert Carlson, MD

While over 100 countries have reported Chikungunya virus (CHIKV) outbreaks in 2024, new research indicates measurable genetic differences could be affecting countries differently, such as Brazil and France's La Réunion.

Published by Frontiers Public Health on December 10, 2024, a Review Article stated that CHIKV is mainly transmitted by the invasive mosquito Aedes (Stegomyia) aegypti in tropical and subtropical regions worldwide.

However, the virus's genetic adaptations to the peridomestic mosquito vector Aedes (Stegomyia) albopictus have enhanced vector competence and associated epidemics.

This finding may contribute to the further geographic expansion of sub-lineage CHIKV.

This review of the CHIKV genotypes circulating in Brazil, the spatial and temporal distribution of Chikungunya cases in Brazil, and susceptibility to infection and transmission of Ae. albopictus for CHIKV focused on understanding the relative contribution to outbreak dynamics.

These insights are essential as Brazil has reported 416,087 CHIKV cases and 211 related fatalities as of week #53 in 2024.

In Brazil, the mid-sized city of São José do Rio Preto in northwestern São Paulo state is considered hyperendemic for arboviral diseases such as Chikungunya. A new study reported on December 6, 2024 that the number of CHIKV cases in this Brazilian state has significantly increased in recent years.

Furthermore, São Paulo remains Brazil's most internationally visited state, with over one million visitors, many of whom arrive from the United States.

These researchers wrote, 'Although CHIKV is generally transmitted by Ae. aegypti mosquitoes, the outbreak that occurred in La Réunion island was caused by Ae. albopictus, which acted as the primary vector due to the ECSA CHIKV genotype adaptation to this vector, as the E1-A226V, resulted in a dramatic increase in this clade's infectivity.

As a result of the increased viral fitness and vector competence, the virus transmission spread to temperate areas and caused epidemics in regions that lack the typical vector, Ae. aegypti.

The emergence of the E1-A226V mutated CHIKV during the La Reunion outbreak is a well-characterized example of how a single nucleotide mutation in a virus may lead to a new epidemiological scenario given specific ecological conditions.'

The complete, unedited article is posted at this link.

Several governments approved using an innovative vaccine in 2023 to curtail future CHIKV outbreaks. As 2024 comes to a close, Valneva SE's IXCHIQ® chikungunya vaccine is recommended for international travelers.

IXCHIQ is available at travel clinics and pharmacies in the U.S.

Sub Title:

Chikungunya virus E1-A226V mutation enhances transmission dynamics

References:

Spatial–temporal distribution of chikungunya virus in Brazil

Chikungunya in Reunion in 2024

Entomological surveillance during a major CHIKV outbreak in northwestern 2 São Paulo

Chikungunya viruses containing the A226V mutation

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Will the U.S. FDA Approve Brazil's Dengue Vaccine

Donald Hackett — Tue, 17 Dec 2024 16:35:14 +0000

Reviewer:

Robert Carlson, MD

With over 12.7 million dengue virus cases and 7,828 related fatalities in 2024, countries throughout the Region of the Americas are seeking access to innovative vaccines.

The United States is one of those countries needing a dengue vaccine.

To potentially meet demand next year, the Butantan Institute today announced that it submitted the last batch of documents required for the registration of its dengue vaccine candidate (Butantan-DV) to Brazil's National Health Surveillance Agency (Anvisa).

With this, the Institute completed the submission of information. This phased evaluation tends to speed up the registration release process.

Butantan-DV, if approved, will be the world's first single-dose vaccine against dengue.

"The fact that the Butantan Institute can contribute with the world's first single-dose vaccine against dengue shows that it is worth investing in research conducted in Brazil and in the internal development of immunobiologicals. We will wait and respect all Anvisa procedures. But we are confident in the results that will come," commented Esper Kallás, director of the Butantan Institute, in a press release on December 16, 2024.

This announcement does not mean Butantan-DV will be available to Brazilians immediately after registration approval. If Anvisa's registration opinion is positive, the Institute must request price approval from the Chamber of Drug Market Regulation, which sets the price of new drugs in Brazil.

After this assessment, the National Commission for the Incorporation of Technologies into the Unified Health System will study the possibility of incorporating the vaccine into the local system.

From an efficacy perspective, Butantan-DV is very protective.

The vaccine's clinical studies were completed in June 2024, when the last participant completed five years of follow-up. Recently, results from phase 3 of the clinical trial, published in The Lancet Infectious Diseases, showed 89% protection against severe dengue and prolonged efficacy and safety for up to five years.

In the U.S., dengue vaccine access has been disrupted in 2024.

The one approved dengue vaccine has been withdrawn from the market, and Takeda withdrew its application to the U.S. FDA to approve its dengue vaccine.

As of December 17, 2024, people living in areas reporting locally acquired dengue, such as Miami, Los Angeles, and San Juan, Puerto Rico, do not have access to preventive vaccines.

Furthermore, the CDC's updated Dengue Global Travel Health Advisory does not include a disease prevention option for travelers to 23 countries.

Many international travelers hope governments will approve next-generation dengue vaccines and candidates in 2025, potentially increasing access.

Sub Title:

Butantan-DV is a single-dose effective safe dengue vaccine

Reference:

Butantan asks Anvisa to register its dengue vaccine, the world's first single-dose vaccine

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US CDC Dengue Global Alert - December 16, 2024

Chikungunya and Dengue Viruses Co-Circulate In the Americas

Karen McClorey Hackett — Thu, 21 Nov 2024 23:56:15 +0000

Reviewer:

Robert Carlson, MD

The sudden multi-year increase of chikungunya (CHIKV) and dengue cases in the Federative Republic of Brazil has raised concerns about the impact of arbovirus outbreaks on public health throughout the Region of the Americas.

As of November 21, 2024, the Pan American Health Organization (PAHO) had reported 412,089 chikungunya cases this year, 411,548 cases in 2023, and 273,841 in 2022.

Seperately, the PAHO has reported 12,522,878 dengue cases and 7,598 related fatalities in 2024.

A recent study published by BMC Medicine has revealed where these mosquito-transmitted diseases are most prevalent.

The data from CHIKV tests indicated that Brazil's Northeast region had the highest regional positivity rate in 2022 (58.1%). However, in 2023, the Southeast region recorded the highest positivity rate (40.5%).

During the first thirty epidemiological weeks of 2023 in Minas Gerais, a Brazilian state with 20 million residents, there was a 5.8-fold increase in CHIKV cases and a 3.5-fold increase in dengue compared to the same period in 2022.

All CHIKV clades are closely related to genomes from previous Brazilian outbreaks in the Northeast.

In 2024, different importation and local transmission events of two distinct genotypes were identified: CHIKV-Asian in the North region and ECSA in the Northeast region of Brazil. All sequenced genomes were classified as ECSA genotype. The dated phylogenetic analysis showed the presence of three main CHIKV clusters.

Furthermore, these researchers detected the RNA of both viruses in approximately 12.75% of the confirmed positive cases, suggesting an increase in co-infection with dengue and CHIKV during the analysis period.

In contrast to CHIKV, dengue cases were not concentrated in just one region of the state. The South region exhibited the highest regional positivity rate in 2022 (40.8%) and 2023 (22.7%).

In conclusion, these researchers wrote, 'The study findings offer valuable insights into two arboviruses in Brazil, particularly in Minas Gerais. These high rates of re-emergence and co-infection with both arboviruses provide useful data for implementing control measures of Aedes vectors and the urgent implementation of public health politics to reduce the numbers of CHIKV and DENV cases in the country.'

To prevent infections, the PAHO suggests that international travelers discuss vaccination options with a travel vaccine expert at least one month before visiting these areas of Brazil. Approved vaccines for chikungunya (IXCHIQ) and dengue (Qdenga) are available.

Sub Title:

Chikungunya vaccine available in 2024

Reference:

Retrospective epidemiologic and genomic surveillance of arboviruses in 2023 in Brazil reveals high co-circulation of chikungunya

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The Lancet

Chikungunya Outbreaks Could be 60 Times More Fatal

Donald Hackett — Wed, 30 Oct 2024 14:49:20 +0000

While the chikungunya virus (CHIKV) was first detected in 2014, its measurable impact on public health is just now being recognized in over 100 countries.

According to a Brief Research Report published by Frontiers in Tropical Disease on October 28, 2024, a significant chikungunya outbreak occurred in Minas Gerais, one of the most populous states in Brazil. These researchers analyzed the North and Northeast Health Macroregions of Minas Gerais, with 2.5 million inhabitants.

During this CHIKV epidemic, there were 890 excess deaths attributed to chikungunya, translating into a mortality rate of 35.1/100,000 inhabitants.

The excess mortality rate was 60 times higher than the deaths reported by surveillance, with only 15 confirmed deaths.

The correlation between excess deaths and laboratory-confirmed chikungunya cases was strong, while the correlation with dengue was not statistically significant.

These study results highlighted the severe underestimation of chikungunya mortality by epidemiological surveillance throughout the Region of the Americas.

During the same year, only 420 chikungunya deaths were reported by all Pan American Health Organization (PAHO) member countries.

In 2024, the PAHO reported over 404,372 CHIKV cases, but only 185 related fatalities in the Americas.

These researchers concluded that 'routine epidemiological surveillance systems cannot capture the full impact of this disease. Excess mortality is a key measure for understanding the impact of epidemics. The study highlights the need for complementary tools to traditional surveillance to assess better impacts on morbidity and mortality and support priority setting in public health interventions.'

Like many vaccines, CHIKV vaccine technologies include live-attenuated virus vaccines, inactivated viral vaccines, recombinant viral vaccines, chimeric-alphavirus candidates, DNA vaccines, and virus-like particles.

As of October 30, 2024, only Valneva SE's IXCHIQ® live-attenuated vaccine has been approved by the U.S. FDA.

IXCHIQ® is the first monovalent, single-dose, vaccine approved to prevent CHIKV infections in adults at increased risk of exposure to this mosquito-transmitted disease.

Sub Title:

Excess mortality associated with chikungunya epidemic in Brazil

Reference:

Excess mortality associated with chikungunya epidemic in Southeast Brazil, 2023

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US CDC Chikungunya Case Map

Brazil Leads The Americas in Dengue Cases

Donald Hackett — Fri, 27 Sep 2024 14:47:02 +0000

Reviewer:

Robert Carlson, MD

Over the past 25 years, nearly 18 million Brazilians have been infected with the dengue virus, and according to recent data, 2024 may become the most severe year ever.

To combat the ongoing dengue outbreak, Brazil's Ministry of Health recently promoted a workshop on assistance support, risk stratification, and implementing new vector control technologies through the Secretariat for Health and Environmental Surveillance (SVSA) and the General Coordination of Arbovirus Surveillance of the Department of Communicable Diseases.

"SVSA's work is essential for implementing new vector control technologies to reduce the incidence of disease and improve the health system's response," said Alda da Cruz, director of the Department of Communicable Diseases, in a press release on September 26, 2024.

This effort is essential in 2024 as Brazil again confronts multiple arbovirus disease outbreaks, such as chikungunya, dengue, and Zika, in 177 locations. The highest dengue incidence rates have been reported in Brazil's Southeast, Central-West, and South.

In the state of Rio de Janeiro, with over 12 million residents, various communities have been identified for their dengue burden.

According to the Pan American Health Organization, about 9.6 million cases of dengue and over 5,400 related fatalities were reported in the first nine months of 2024.

Brazil's National Health Surveillance Agency recommends vaccination for certain persons living or visiting dengue-risk areas. This year, Brazil registered 2.2 million first doses of dengue vaccines.

The Secretary of Health and Environmental Surveillance, Ethel Maciel, recently warned about the need to get vaccinated.

"Within the age range indicated by the laboratory for receiving the vaccine, we selected the interval with the highest number of hospitalizations due to dengue in Brazil. However, this group has a lower adherence rate precisely because they are not an age group that routinely uses health services. Therefore, parents and guardians need to take their children and adolescents to get vaccinated. It is an act of love and responsibility," she highlighted on September 24, 2024.

Even though there is a limited vaccine supply, Brazil is offering Takeda's QDENGA® tetravalent, two-dose vaccine. This second-generation dengue vaccine does not require pre-admission testing.

While QDENGA is not offered in the United States, several countries in the Americas are offering it to people.

To alert international travelers of the dengue risk, the U.S. Centers for Disease Control and Prevention (CDC) reissued a Global Travel Health Notice in September 2024 regarding outbreaks in 28 countries.

The CDC recommends that travelers practice mosquito prevention measures to avoid being infected with one of the four dengue viruses. These mosquitoes can also spread Zika and chikungunya viruses.

While most people recover from dengue infection, women who are infected with dengue virus during pregnancy can pass the virus to their fetus during pregnancy or around the time of birth. The CDC says the dengue virus can become very harmful to infants.

Sub Title:

Dengue vaccination offered in Brazil in 2024

Reference:

Brazil Health Dept - Sept. 2024

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Saturday, September 28, 2024 - 07:15

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U.S. CDC - 28 countries at risk for dengue outbreaks as of Sept. 2024

Brazil Considers Recombinant BCG Vaccine for Infants

Donald Hackett — Wed, 10 Jul 2024 21:24:48 +0000

Reviewer:

Robert Carlson, MD

While most infants in Brazil's five regions are vaccinated against tuberculosis, the search for a more effective Bacillus Calmette-Guérin (BCG) vaccine accelerated in 2024.

Researchers from the Butantan Institute and collaborators confirmed on July 3, 2024, that they are developing a more potent version of the 100-year-old BCG vaccine.

While the conventional BCG vaccine reduces infection by 90% in experiments with mice, the so-called recombinant BCG (rBCG) increased the protection rate to 99%.

In addition, the rBCG formulation protected animals for a significantly more extended period of time (15-20 years).

“BCG is the first vaccine we receive at birth, effectively protecting children. However, immunity against the disease tends to wane in adulthood, and as bacteria become resistant to antibiotics, no one is safe. There’s been a global effort to improve the prevention of pulmonary tuberculosis in adults. Today, there are about 10 million new cases and 1.5 million deaths per year in the world,” commented Agência FAPESP Luciana Cezar de Cerqueira Leite, a researcher at Butantan Institute’s Vaccine Development Laboratory, in a press release.

To understand why rBCG leads to a more robust and longer-lasting immune response, the Butantan group and collaborators have adopted an approach known as systems biology – observing in an animal model the behavior of thousands of genes in different tissues throughout the assembly of the immune response.

This systems biology involves sequencing hundreds of samples, followed by intensive bioinformatics and data mining.

Cerqueira Leite addressed this topic on June 29, 2024.

“We sequenced all the RNA that was expressed and present in samples taken at different times: before the animal was immunized, seven and 90 days after immunization – when the challenge is performed [the bacteria are inoculated into the rodents’ noses] – and seven and 90 days after the challenge,” explains Cerqueira Leite.

“As early as seven days after immunization, a very big change could be seen in the group that received the recombinant version: about 200 genes were already being activated, while almost nothing happened in the conventional BCG group."

"After 90 days, the response to the conventional BCG began to decline, while it remained the same in the recombinant group. But the big news is that the two vaccines work through very different metabolic pathways, and we’ve been able to map them. The data will be published soon,” revealed the researcher.

Through genetic engineering, the rBCG version gained the ability to produce a fragment of a toxin originally secreted by Escherichia coli, a species commonly found in the human gut.

“Some E. coli bacteria produce heat-labile toxins, known by the acronym LT, which are highly immunogenic, i.e., they induce a strong response from the immune system. In the rBCG vaccine, we use a detoxified fragment of the LT toxin [called LTAK63]. It isn’t capable of causing disease, but it maintains immunogenicity, so it acts as an adjuvant to the rBCG vaccine.”

The researcher explained that the first studies using the recombinant BCG strategy were aimed at developing a neonatal pertussis vaccine.

In experiments with an animal model of tuberculosis, rBCG vaccination was found to reduce the amount of bacteria in the lungs a hundredfold and reduce inflammation in the organ.

“In trying to kill the bacteria, the defense cells end up attacking everything nearby and causing tissue damage. However, the lungs of the animals immunized with recombinant BCG are white and less inflamed. By detailing the mechanism of action of the two vaccines, we now understand why this happens.”

According to Cerqueira Leite, the production of the immunizer’s experimental rBCG batches is expected to begin in 2025 following one more round of tests in cattle, and human clinical trials could start in 2026.

The Global Coalition of TB Advocates recently confirmed that there are 16 TB vaccines in use in 2024. As of March 2024, 11 TB vaccine candidates were in late-stage development globally.

In the United States, Merck's TICE® BCG vaccine is U.S. FDA-approved, but has limited distribution.

Note: All RNA sequencing was performed in Shenzhen, China, by the company BGI, which provides genomics services to laboratories worldwide. Researchers from the Shenzhen Institute of Advanced Technology, the University of São Paulo, the Albert Einstein Israelite College of Health Sciences, Fiocruz Bahia, Novartis/GSK, the Institut Pasteur, and the Federal University of Goiânia, among others, collaborated in the studies.

Sub Title:

Recombinant BCG vaccine may increase disease protection over more years

References:

New tuberculosis vaccine results presented at FAPESP Week

Tuberculosis in Brazil: one country, multiple realities

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KARINA TOLEDO

Brazil Declares Bird Flu Emergency

Karen McClorey Hackett — Wed, 24 May 2023 14:38:49 +0000

Reviewer:

Robert Carlson, MD

According to VOA News, Brazil recently declared a state of animal health emergency for the next 180 days in response to the country's first detection of the highly pathogenic avian influenza virus (HAPI) in wild birds.

Brazil's agriculture ministry said on May 22, 2023, it has created an emergency operations center to coordinate, plan and evaluate "national actions related to avian influenza."

Avian influenza A (H5N1) was first detected in the Americas in December 2014, and since January 2022, over 58 million birds in 47 states have been culled following HAPI detections in the U.S.

As of May 18, 2023, the Pan American Health Organization (PAHO) reported H5N1 viruses (clade 2.3.4.4b) had been detected in birds in 16 countries in Latin America, the Caribbean, the U.S., and Canada.

The identified outbreaks are mainly located in areas of the Pacific flyway, says the PAHO.

While infection by HAPI in wild birds does not trigger trade bans, based on guidelines of the World Organization for Animal Health, a case of bird flu on a farm usually results in the entire flock being culled.

On May 22, 2023, Brazil's Agriculture Minister Carlos Favaro confirmed a significant economic risk to the HAPI outbreak.

Brazil is one of the world's biggest chicken meat exporters, with $9.7 billion in sales in 2022.

Though Brazil's central meat-producing states are in the southern area, the government is on alert after the recent HAPI detections.

The World Organization for Animal Health confirmed on May 15, 2023, two terns were found infected with H5N1 on Brazil's coast of Espirito Santo state.

During the recent HAPI outbreak, infections have been reported in various birds, mammals, and people as of May 24, 2023.

Should a cross-over pandemic occur, the U.S. government has approved one vaccine for HAPI that protects people from infection and severe disease and is actively supporting other bird flu vaccine candidates.

However, the U.S. CDC says the annual flu shots were not designed to protect people against avian influenza infections.

Sub Title:

Brazil is a leading chicken meat exporter

References:

VOA - Brazil Declares Health Emergency Amid Avian Flu Cases in Wild Birds

U.S. CDC H5N1 Bird Flu Detections May 2023

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National Fish and Wildlife Foundation May 2023

Can Yellow Fever Vaccination End Outbreaks

Karen McClorey Hackett — Mon, 01 May 2023 18:10:36 +0000

Reviewer:

Robert Carlson, MD

In the Region of the Americas, the risk of yellow fever outbreaks remains high in 2023, while vaccination coverage for this preventable disease has stagnated over the past decade.

According to the Pan American Health Organization (PAHO) epidemiological update, confirmed cases of yellow fever were reported last year in several countries led by Bolivia (5 confirmed cases), Brazil (5 cases, including four deaths), and Peru (7 confirmed cases, including five deaths.

As of April 25, 2023, additional yellow fever cases have been recorded this year in Bolivia (two cases) and Brazil (three cases).

The PAHO says yellow fever is an acute viral hemorrhagic disease that can quickly become fatal.

Once contracted, the yellow fever virus incubates in the body for 3 to 6 days. Many people do not experience symptoms, but when these occur, the most common are fever, muscle pain with prominent backache, headache, loss of appetite, and nausea or vomiting.

In most cases, symptoms disappear after 3 to 4 days.

However, a small percentage of patients enter a second, more toxic phase within 24 hours of recovering from initial symptoms.

About half of the patients who enter the toxic phase die within 7 - 10 days.

In addition to the Americas, various African countries have reported outbreaks in 2023.

The good news is effective and safe yellow fever vaccines have been available for over 80 years, and over 850 million doses have been distributed worldwide.

A single dose is enough to confer immunity and protection for life without needing a booster dose, says the PAHO.

In addition to immunizing the at-risk population, countries should vaccinate visitors entering at-risk areas.

And the Eliminate Yellow Fever Epidemics program, driven by PAHO, seeks to vaccinate nearly one billion people against yellow fever by 2026.

In the U.S., Sanofi Pasteur's YF-VAX® vaccine has been available since April 5, 2021.

The International Certificate of Vaccination or Prophylaxis, known as the yellow card, is issued after vaccination.

This vaccine is only available at authorized locations like Houston, Texas.

Sub Title:

Brazil yellow fever outbreak continue in 2023

References:

PAHO Epidemiological Update - Yellow fever in the Region of the Americas - 25 April 2023

Yellow fever vaccines 2023

WHO: global strategy to eliminate yellow fever epidemics

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PAHO map of Brazil yellow fever cases April 25, 2023

Unusual Antibody Displays Ultrapotent Activity Against Zika Virus

Karen McClorey Hackett — Tue, 06 Dec 2022 19:42:22 +0000

Reviewer:

Robert Carlson, MD

The peer-review journal Cell recently published a study that identifies a role for antibodies of the IgM isotype in protection against the Zika virus (ZIKV) and posits it is a safe and compelling candidate for immunotherapeutic, particularly during pregnancy.

Because ZIKV can cause congenital disabilities when passed to a fetus, this discovery could lead to the development of therapies to protect babies from the potentially devastating effects of this mosquito-borne disease.

This finding is essential since congenital ZIKV infections result in neurodevelopmental deficits in up to 14% of infants born to ZIKV-infected mothers.

Furthermore, the U.S. FDA has not approved a ZIKV vaccine candidate as of December 6, 2022.

Neutralizing antibodies are a critical component of protective immunity, stated researchers from Weill Cornell Medicine, NewYork-Presbyterian and National Institutes of Health investigators.

From a ZIKV-infected pregnant woman, they isolated a pentameric ZIKV-specific IgM (DH1017.IgM) that exhibited ultrapotent ZIKV neutralization dependent on the IgM isotype.

They demonstrated that plasma IgM contributes to ZIKV immunity in pregnancy, mediating neutralization up to three months post-symptoms.

DH1017.IgM targets an envelope dimer epitope within domain II. The epitope arrangement on the virion is compatible with the concurrent engagement of all ten antigen-binding sites of DH1017.IgM, as a solution not available to IgG.

DH1017.IgM protected mice against viremia upon lethal ZIKV challenge more efficiently than when expressed as an IgG.

According to the study co-senior author Dr. Sallie Permar, the important thing is that we've got to be ready for another outbreak of Zika.

At this point, doctors have no approved vaccines or treatments to offer patients. However, with further research, this antibody has the potential to help fill that gap, according to Dr. Permar.

"There are two potential ways it could be used: To quickly reduce levels of Zika in the blood of pregnant people who have become infected, or as a preventative measure given to those at risk of contracting the virus during an outbreak," stated Permar in a press release on November 18, 2022.

To develop the antibody into a real-world therapy, the researchers plan to test its safety and how effectively it can prevent transmission to a fetus in additional preclinical models.

Dr. Permar emphasized that when human studies for new preventive or therapeutic treatments are done for Zika, they must be included. "Pregnant women, the population that needs vaccines or immunotherapies for Zika."

"It's crucial to get anti-Zika vaccines and therapies that are safe in pregnancy rolled out as soon as there is evidence of an outbreak."

While infected mosquitoes primarily spread ZIKV, it can also be passed during sex from a person infected with ZIKV to a sexual partner, says the U.S. CDC.

As of December 2022, Brazil, India, and Puerto Rico (15 probable) have reported Zika cases.

This research was supported by NIAID grant R21-AI123677.

Many Weill Cornell Medicine physicians and scientists maintain relationships and collaborate with external organizations to foster scientific innovation and provide expert guidance.

ZikaNews publishes fact-checked, research-based news manually curated for mobile readers.

Sub Title:

Zika virus-specific IgM elicited in pregnancy exhibits ultrapotent neutralization

References:

Zika virus-specific IgM elicited in pregnancy exhibits ultrapotent neutralization

Zika: Weill Cornell Medicine, NewYork-Presbyterian and NIH investigators

Neutralizing Zika virus

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Birth

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by Lando Hamukwaya