Vaccine News

The World Health Organization's Disease Outbreak News recently reported a fatal case of Chapare hemorrhagic fever (CHHF) from the La Paz Department in the Plurinational State of Bolivia.

As of January 20, 2025, no secondary cases have been reported.

The WHO defines Chapare hemorrhagic fever as an acute viral illness caused by the Chapare virus. The rodent-borne Chapare virus is an Arenavirus that can cause hemorrhagic fevers like Ebolaviruses.

Initially identified in Cochabamba in 2003, five documented outbreaks have occurred within Bolivia.

The most recent outbreak occurred in 2024, with one laboratory-confirmed case within the La Paz Department. This area in Bolivia, which has a population of about 3 million, is a neighbor of Peru.

As of January 22, 2025, the WHO says there is no significant risk of the disease spreading internationally. Person-to-person transmission of the Chapare virus is possible but remains rare in the general population. 

The U.S. CDC says CHHF is a rare, deadly viral disease. About 20% to 60% of people with the disease die.

Furthermore, there are no treatments or preventive vaccines available for CHHF.

When visiting Bolivia in 2025, the CDC recommends several travel vaccinations, such as chikungunya and yellow fever. These vaccines are offered at many travel clinics and pharmacies in the U.S.

The reemergence of yellow fever in the Brazilian state of São Paulo over the past 23 years has highlighted the need to be fully immunized before visiting endemic areas in 2025.

The São Paulo State Health Department recently confirmed the first human yellow fever case in January 2025.

According to a study published by Rev Bras Epidemiol in December 2024, five yellow fever outbreaks from 2000 to 2023 led to 679 human cases. Epizootic surveillance actions in non-human primates intensified in 2017 when the virus circulated in areas without vaccine recommendations in the state.

A previous study found the metropolitan region of São Paulo city YF outbreak during 2017–2018 revealed that 36 deaths were due to three genetic variants of sylvatic YFV that belong to the South American I genotype and that were related to viruses previously isolated from other locations in Brazil (Minas Gerais, Espírito Santo, Bahia, and Rio de Janeiro states).

According to these researchers, each variant represented an independent YF virus introduction into Sao Paulo.

"The recently confirmed case of yellow fever infection in São Paulo reinforces the importance of vaccination before traveling to many parts of Brazil, including popular urban destinations," commented Jeri Beales, MSN, RN.

"The 2017 yellow fever outbreak in Brazil marked an important change in CDC yellow fever recommendation for Brazil-bound travelers, including major cities like São Paulo, Rio de Janeiro, Curibita, and Salvador."

"Ideally, the yellow fever vaccine is given at least 10 days before arrival to a risk area, and only clinics certified with CDC can provide the vaccine," added Beales, who leads Destination Health Clinic, a Boston-area travel health provider specializing in health education and vaccination for international travelers.

As of January 21, 2025, the U.S. CDC and the U.K. Health Security Agency recommends international travelers visit a travel clinic or pharmacy to discuss travel vaccine options about one month before visiting Brazil in 2025. This year, about 8 million people may visit Sao Paulo.

According to the CDC, the yellow fever vaccine is recommended for many destinations in Brazil, including Sao Paulo, but may not required for entry.  

Note: This Vax-Before-Travel news article was updated with related insight on Jan. 22, 2025.

In 2024, many European countries detected poliovirus in wastewater systems, signaling the once-eradicated disease's potential resurgence.

According to the Global Polio Eradication Initiative (GPEI), poliovirus continues to be detected in Bonn, Nordrhein-Westfalen, Sachsen, and Bayern, Germany. As of January 15, 2025, eleven circulating vaccine-derived poliovirus type 2-positive environmental samples were collected in November and December 2024.

This pathogen is not the wild poliovirus type but originates from the oral polio vaccine, which contains weakened but live polioviruses. The weakened vaccine viruses can be excreted and spread by vaccinated people.

Germany's last case of wild poliovirus was recorded in 1990.

The GPEI has confirmed that various countries have also reported cases of wild polio, vaccine-derived poliovirus type 2, and circulating vaccine-derived poliovirus type 1.

On January 15, 2025, the U.S. Centers for Disease Control and Prevention (CDC) identified 39 countries at-risk for polio. This CDC list does not include Germany or the United Kingdom.

Last year, Dr Hans Henri P. Kluge, WHO Regional Director for Europe, commented in a press release, “For over 20 years, sustained efforts to achieve high vaccination coverage, quality surveillance, and rapid outbreak response have prevented the virus from re-establishing in this Region. These efforts must be commended, but also intensified as challenges to our collective defense against this virus increase.” 

The CDC and the WHO recommend that all travelers to polio-affected areas in 2025 be fully vaccinated, and some people may qualify for a polio vaccine booster dose.

Since 2023, the U.S. FDA has approved the Chikungunya virus vaccine, which has been deployed in various countries to curtail outbreaks, with exceptional efficacy data reported by multiple studies.

Adding to this positive trend, Valneva SE today reported further positive Phase 3 clinical trial data in adolescents for its single-shot chikungunya virus vaccine, IXCHIQ®. The vaccine showed a sustained 98.3% sero-response rate one year after a single vaccination.

These results support and strengthen the pivotal data previously reported for adolescents (12 to 17 years old), which supported filing for potential label extensions for this age group in the U.S., Europe, and Canada.

Data from this trial are also expected to support the licensure of IXCHIQ® in Brazil, which would be the first potential approval for use in Chikunguna endemic populations.

Juan Carlos Jaramillo, M.D., Valneva's Chief Medical Officer, commented, “These additional adolescent data confirm IXCHIQ®’s ability to induce a robust, long-lasting antibody response in both younger people and adults with a single vaccination."

"Given the substantial risk that chikungunya presents to individuals residing in or traveling to endemic regions, it’s imperative to ensure the vaccine is available to all age groups and has the potential to offer long-term protection, particularly in low- and middle-income countries where vaccine access is often limited."

"We are now looking forward to the first data in children, which we expect to report imminently.”

Chikungunya outbreaks have been recorded as early as 1824 in India. In 2024, over 425,00 cases and 236 related fatalities were reported in the Region of the Americas.

So far, in 2025, there have been 523 Chikungunya cases in Brazil. 

IXCHIQ® is the only licensed Chikungunya vaccine available at travel clinics and pharmacies in the U.S.

The Houston Health Department (HHD) recently announced two measles cases associated with international travel. Both adults reside in the same Houston, Texas household and have unknown vaccination statuses.

HHD stated these are the first reported measles cases in Houston since 2018.

Texas experienced a travel-related measles outbreak in 2019, which led to 23 cases.

Measles was officially eliminated from the United States in 2000. However, as of late December 2024, 32 U.S. jurisdictions, led by Illinois and Minnesota, had reported 284 cases, many of which were travel-related.

Internationally, the U.S. Centers for Disease Control and Prevention (CDC) maintains a global Watch-Level 1 Travel Health Notice identifying measles outbreaks in 59 countries last year.

As of January 19, 2025, HHD and the CDC say the most effective way to prevent measles virus infections is to get the measles, mumps, and rubella (MMR) vaccine. Measles vaccination services are offered at most travel clinics and pharmacies. 

Despite spending $4 billion annually, the number of malaria cases and deaths has not significantly changed over the past decade, especially in Africa. Last year, the WHO's African Region reported the broadest malaria outbreak burden.

Based on today's U.S. Centers for Disease Control and Prevention (CDC) Travel Health Advisory, health agencies are not optimistic about seeing any improvement in this trend by 2025.

Today, the CDC confirmed an ongoing malaria outbreak in the Federal Democratic Republic of Ethiopia, affecting all 14 country regions. More than 8.4 million malaria cases were reported, the highest number of cases ever reported within a year.

To bolster Ethiopia’s fight against malaria, the United States Government, through the U.S. Agency for International Development, donated 175 computer terminals to the Ethiopian Public Health Institute on January 15, 2025.

Additional U.S. support includes over $27.5 million of antiretroviral supplies, early infant diagnostics, quality assessment panels, lab equipment, and more.

Malaria is a disease caused by a parasite that spreads to humans through the bite of infected mosquitoes, commonly found in Africa.

If you plan to travel to Ethiopia in 2025, the CDC recommends speaking with a travel health expert about which antimalarial drug is best for you. And seek medical care immediately if you develop fever, chills, sweats, headache, vomiting, or body aches during or after travel to Ethiopia. 

In 2024, numerous international travelers brought malaria back with them.

As of the week ending November 23, 2024, the CDC confirmed 1,772 malaria cases, mostly among international travelers arriving in New York City (232), Texas, Miami, Florida, and Los Angeles, California. 

While malaria vaccines are available in Africa, they are not FDA-approved in the U.S. and remain unavailable in the U.S.

Furthermore, innovative vaccine candidates, such as the RH5.1/Matrix-M malaria vaccine, are proceeding in late-stage clinical trials. Developed at the University of Oxford, this vaccine targets blood-stage malaria, unlike previously approved vaccines that target the pre-erythrocyte stage. 

The Pan American Health Organization (PAHO), the Government of Argentina, and others today announced a joint effort to facilitate local production and regional access to the 20-valent pneumococcal conjugate vaccine (PCV20).

This vaccine is expected to further protect against severe diseases caused by Streptococcus pneumonia  (pneumococcus), responsible for pneumonia, meningitis, and other serious infections, including those linked to antibiotic-resistant strains.

In 2021, 3,345 children under the age of 5 died due to pneumonia and meningitis caused by pneumococcus in Latin America and the Caribbean.

Through this initiative, not only will Argentina benefit from local production of the PCV20 (PREVNAR 20®), but countries across the Region of the Americas will be able to access vaccine doses through PAHO’s Regional Revolving Funds, ensuring more rapid vaccine rollout at competitive prices.

The PCV20 vaccine will be available in Latin America and the Caribbean starting in early 2025. The first doses produced in Argentina are estimated to be available by 2026.

“PAHO is committed to boosting regional production of sustainable, innovative technologies by strengthening existing capacities and our regional purchasing mechanism, the Revolving Fund for Access to Vaccines,” said PAHO Director Jarbas Barbosa in a press release on January 15, 2025.

“This collaboration reflects our dedication to ensuring equitable access to safe, effective vaccines that prevent severe diseases and save lives,” he added.