Vaccine News

The New York City Health Department (NYCDH) recently confirmed the city's first known case of mpox clade I, a more severe strain of the sexually transmitted virus.

This case, announced by NYCDH on March 13, 2026, involves an individual who recently traveled to Europe. Officials have emphasized that this infection is travel-related, with no evidence of local transmission in New York City or its five boroughs.

The affected person has developed symptoms, sought medical care, and is currently isolating until their symptoms resolve completely.

Currently, NYCDH has not publicly disclosed the specific borough, neighborhood, ZIP code, or any other precise location within NYC for this mpox case.

"There is no known local transmission of mpox clade I in New York City, and the risk remains low for New Yorkers," stated NYC Health Commissioner Dr. Alister F. Martin.

As of today, there have been twelve clade I mpox diagnoses reported in the United States.

Clade I mpox, which is associated with ongoing outbreaks in parts of Africa, can cause more severe illness than the clade II strain responsible for the global outbreak that began in May 2022. Symptoms typically include a painful rash, fever, chills, swollen lymph nodes, and muscle aches.

The virus spreads primarily through close or intimate contact, including sexual contact.

NYCDH stressed that while the public risk is low, vaccination remains a key preventive tool, especially amid international travel.

NYC officials and the U.S. CDC continue to recommend Bavarian Nordic's JYNNEOS® (MVA-BN®) vaccination for at-risk groups.

A meta-analysis of 16 studies published in 2024 revealed that the vaccine efficacy (VE) for a single preexposure prophylactic JYNNEOS dose ranged from 35% to 86%, and the VE for two doses ranged from 66% to 90%.

As the 2025-2026 influenza season comes to an end, the U.S. government recently released early data regarding the effectiveness of this year's flu shot.

On March 12, 2026, the U.S. CDC's Morbidity and Mortality Weekly Report (MMWR, 75(9);124–128) noted that influenza vaccine effectiveness (VE) can vary each year based on several factors, including the antigenic similarity between the vaccine and circulating viruses, as well as patient characteristics. VE can be estimated using data from paired laboratory surveillance and vaccination records.

According to the MMWR, the estimated VE against laboratory-confirmed influenza for all age groups in California during the period from October 2025 to January 2026 was 33% (32% effectiveness against influenza A and 47% against influenza B).

The CDC stated that these results suggest that influenza vaccination is associated with a decreased likelihood of laboratory-confirmed influenza among both children and adults.

Furthermore, the CDC recommends annual influenza vaccination for all individuals aged 6 months and older to reduce the risk of influenza and its associated adverse health outcomes.

Additionally, some individuals located in high-risk areas may consider receiving a second flu shot in the later stages of flu season.

For the fast-approaching 2026-2027 flu season, the Vaccine and Related Biological Products Advisory Committee recently endorsed recommendations for viral strains to include in flu shots.

Anguilla, a British Overseas Territory located in the Eastern Caribbean, has recently reported its first locally acquired case of West Nile virus (WNV). According to a Facebook post from the Ministry of Health, Tourism, and Sports dated March 11, 2026, this confirmation marks the first documented human case of WNV in Anguilla.

WNV has been present in the Caribbean since at least 2002, when it was detected in birds in Guadeloupe. However, large-scale human epidemics similar to those in North America, including the United States, have not occurred as of March 13, 2026.

This news is concerning for the over 220,000 international travelers expected to visit Anguilla this year. WNV primarily circulates between mosquitoes and birds, which serve as its main hosts. The virus is transmitted to humans through the bite of infected mosquitoes; however, humans do not spread the virus to others.

Most WNV infections are mild or asymptomatic, with an overall mortality rate of about 1% among those infected.

To protect against the disease, the Ministry of Health advises residents to eliminate mosquito breeding sites and take measures to prevent mosquito bites, as these are the most effective ways to safeguard themselves.

Additionally, the U.S. Centers for Disease Control and Prevention notes that no licensed vaccines or specific medications are available to prevent or treat WNV in humans. Fortunately, vaccine candidates for WNV have been tested in clinical trials.

Over the decades, Chikungunya cases have been reported in approximately 100 countries. In India, the number of cases of this mosquito-borne disease has varied over time. 

As of mid-March 2026, comprehensive nationwide annual totals are not yet available. However, early reports indicate ongoing activity in India, with a rise in Chikungunya cases, particularly in states like Tamil Nadu and Maharashtra. 

Provisional data for last year shows over 165,000 suspected cases and 95 related fatalities in 2025.

To reduce the number of infections and enhance the local economy, two pharmaceutical companies today announced an innovative agreement.

Bavarian Nordic A/S announced an expansion of the strategic partnership with Serum Institute of India Pvt. Ltd. (SII) to include a contract manufacturing agreement covering a full tech transfer of the manufacturing process for the Chikungunya vaccine (Vimkunya®, CHIKV VLP) to allow for scaling of capacity to enable future supply to endemic low- and middle-income countries.

"We are pleased to strengthen our strategic partnership with SII. By leveraging the strengths of both organizations, we can scale manufacturing of our chikungunya vaccine to expand global supply and improve access for populations around the globe," said Paul Chaplin, President & CEO of Bavarian Nordic, in a press release.

As of March 11, 2026, this agreement builds on the existing mpox vaccine license and manufacturing agreement with SII and replaces the agreement previously entered into with Biological E. Limited.

This Chikungunya vaccine does not contain viral genetic material and is therefore non-infectious and unable to cause disease, ensuring a broad range of people can benefit from vaccination.

Vimkunya® was approved by the U.S. Food and Drug Administration, the European Commission, and the U.K. Medicines & Healthcare products Regulatory Agency in 2025. Regulatory review of the vaccine is ongoing in Switzerland and Canada.

As of March 12, 2026, Vimkunya® is commercially available at various travel vaccine clinics in the U.S. and is recommended for those visiting Chikungunya risk areas, such as India.

The Republic of Maldives is facing a troubling increase in Dengue fever cases in early 2026, which could impact its expanding number of international visitors.

Health authorities have reported 631 confirmed cases in January 2026 alone, according to the latest data from the Health Protection Agency (HPA).

The HPA figures indicate a significant upward trend, with reports suggesting cases are nearly six times higher than in January 2025. The highest numbers of cases have been reported in areas such as Vaavu Atoll, Kaafu Atoll, and Gaafu Alif Atoll.

This surge in Dengue cases follows a pattern of rising activity observed in the Maldives, an archipelagic country in the northern Indian Ocean, toward the end of 2025. Dengue has been endemic in the Maldives and neighboring countries, including Sri Lanka, which has reported 5,471 cases, and India, which has reported 3,019 cases this year.

Despite this significant public health concern, the Maldives is on track for a record-breaking year in tourism, with the government officially targeting 2.5 million tourist arrivals for the full year.

Dengue is a vaccine-preventable disease. The primary Dengue vaccine available globally is Qdenga®.

However, there is currently no evidence that Qdenga has been included in the Maldives' national immunization program. Recent vaccination initiatives in the country have focused on other vaccines, such as those for rotavirus and pneumococcal disease.

To alert international travelers, the U.S. Centers for Disease Control and Prevention (CDC) recently issued a Level 1 notice that classifies the Maldives as having a frequent and continuous risk of Dengue, noting that local transmission has occurred in multiple years.

International travel health guidelines from the CDC emphasize mosquito-bite prevention as the main defense for visitors to the Maldives, recommending vaccination only for individuals with prior evidence of Dengue infection in specific high-risk situations.

Given that Dengue remains a year-round threat in the Maldives and elsewhere, health officials advise travelers to consult a vaccine expert before visiting this tropical paradise in 2026.

French health authorities are reporting a significant increase in cases of chikungunya virus disease in Mayotte, an overseas department in the Indian Ocean. Since the beginning of 2026, more than 270 confirmed cases have been recorded.

This surge indicates a concerning resurgence of the mosquito-borne illness on the island, following a major outbreak in 2025 that affected thousands across the Indian Ocean region, including neighboring departments such as La Réunion.

According to the French Regional Health Agency, Mayotte reported approximately 1,270 cases last year, primarily in Grande-Terre. Surveillance data from Santé Publique France and the European Centre for Disease Prevention and Control (ECDC) show that the weekly average of cases in the last two weeks of February 2026 was around 65.

Most chikungunya cases are believed to be locally transmitted, influenced by favorable conditions for the Aedes mosquito vectors during the current rainy season, which typically supports higher mosquito populations and the spread of the virus until about April.

As of March 11, 2026, the ECDC has assessed the risk of chikungunya infection for travelers to Mayotte as moderate. In its recent Communicable Disease Threats Report, the agency highlighted the ongoing circulation of the virus and recommended enhanced preventive measures.

"Travelers should be advised to take enhanced measures to prevent mosquito bites."

ECDC recommendations include using insect repellents containing DEET or other approved ingredients, wearing long-sleeved clothing and long pants, and sleeping under insecticide-treated bed nets, especially during daytime hours when Aedes mosquitoes are most active.

Santé Publique France indicated that the outbreak is expected to continue in the coming months unless conditions change significantly. Travelers planning visits to Mayotte are encouraged to consult travel health clinics. In 2025, Santé Publique France reported about 800 locally acquired chikungunya cases on the mainland. 

The U.S. CDC, which issued a Level 2 – Practice Enhanced Precautions Notice on March 10, 2026, continues to monitor the situation closely and will update guidance as needed to protect both residents and the expected 75,000 visitors from this preventable but debilitating disease.

The CDC writes, "If you are pregnant, reconsider travel to the affected areas, particularly if you are close to delivering your baby. Mothers infected around the time of delivery can pass the virus to their baby before or during delivery. Newborns infected in this way or by a mosquito bite are at risk for severe illness."

Both the ECDC and CDC say vaccination against chikungunya may be recommended for travelers based on national guidelines and individual risk assessments. In some countries, such as the United States, vaccines are available for at-risk groups.

As spring break 2026 approaches, many American families and students are heading to the beaches and eco-adventures in the Republic of Costa Rica.

Given this peak travel period, visitors arriving at Juan Santamaría International Airport in San José and Daniel Oduber Quirós International Airport in Liberia are advised to stay informed about health precautions.

Today, the Costa Rica Ministry of Health confirmed a second case of measles in 2026. Health authorities, including teams from the Ministry of Health and the Costa Rican Social Security Fund, have activated epidemiological protocols. They are currently investigating potential sources of infection through contact tracing and risk factor analysis.

On March 9, 2026, the Ministry requested the temporary suspension of classes at Moravia High School and halted activities related to a program by the Ministry of Culture and Youth. Earlier this month, a measles patient was isolated to prevent further transmission of the virus.

Last year, there was an imported case of measles recorded in Guanacaste, involving an unvaccinated traveler from Canada.

The Costa Rica health agencies urge travelers, especially families with young children and those without up-to-date measles-mumps-rubella (MMR) vaccinations, to check their vaccination status. However, proof of MMR vaccination is not currently required for airport entry.

The MMR vaccine is routinely available through Costa Rica's national health system, and vaccination campaigns have been intensified due to recent alerts.

So far, no additional cases or outbreaks have been reported in connection with the current incident, and authorities are maintaining surveillance to contain any potential spread.

For the latest updates on the global measles outbreak, visit Vax-Before-Travel.com.

And for security advisories, visit the U.S. Department of State, which has published a Level 2 notice for Costa Rica.