Vaccine News

An extensive real-world study published in the Journal of Infection suggests that the long-acting monoclonal antibody nirsevimab (Beyfortus) provides protection against respiratory syncytial virus (RSV) infection for children younger than 2 years for up to one year.

Published on November 6, 2025, this study found RSV infection was confirmed in 8.5%, 8.0%, and 20.7% of children who received nirsevimab within 6 months, from 6 to 11 months, and beyond 12 months before RSV testing, respectively, while 16.6%, 17.7%, and 17.3% of those who didn't receive nirsevimab were infected in each corresponding period. 

These researchers wrote that the results of this study may stimulate discussions regarding repeated dosing schedules for infants and young children. 

Grants from the Japan Agency for Medical Research and Development and others supported this research.

Nirsevimab has been approved and is used in several countries, including the United States, to prevent RSV infections and their associated severe outcomes.

When the U.S. Centers for Disease Control and Prevention (CDC) issued a Level 1 - Practice Usual Precautions notice in September 2025, it highlighted that the bites of infected midges and mosquitoes are spreading the Oropouche virus in Cuba.

As of November 7, 2025, a total of 4,119 locally acquired Oropouche cases have been reported in Cuba this year.

In South America, Brazil leads the Americas with about 12,000 cases.

Last year, 103 cases of Oropouche virus were reported among individuals in Florida who had traveled to endemic areas, such as Brazil and Cuba.

Currently, no vaccines are available to prevent Oropouche disease, says the CDC.

The Government of the Hong Kong SAR's Center for Health Protection (CHP) of the Department of Health today announced a third locally acquired case of chikungunya fever (CF) in a middle-aged man living in the Kwai Tsing District and working in Sheung Wan.

As of November 4, 2025, the CHP will conduct genome analysis to determine whether it has epidemiological linkage to the imported cases confirmed earlier in Hong Kong. Investigation is ongoing.

Kong Kong's initial CF case was reported on October 28, 2025.

In response to the new local case, the CHP today has conducted an inter-departmental meeting with various departments and relevant organisations.

To alert international travelers to the expanding CF health risk in this region, the U.S. CDC published a Level 2—Practice Enhanced Precautions —Travel Health Notice in late August 2025.

The CDC stated that you can protect yourself by preventing mosquito bites, which includes using insect repellent, wearing long-sleeved shirts and pants, and staying in places with air conditioning or with screens on the windows and doors. 

Additionally, the CDC recommended vaccination for certain travelers visiting areas with chikungunya outbreaks. In general, vaccination against chikungunya should be deferred until after delivery for pregnant women.

In the United States, approved chikungunya vaccines are commercially available at travel clinics and pharmacies.

The Florida Department of Health recently published its Vaccine-Preventable Diseases Surveillance Report #44 for 2025, revealing a continuation of locally acquired and travel-related mosquito-transmitted disease cases.

As of November 1, 2025, Chikungunya, Dengue, and Malaria patients were primarily identified along Florida's southeast coast.

This year, 42 travel-related Chikungunya cases have been confirmed in Broward, Collier, Lake, Miami-Dade, Palm Beach, and Seminole counties. The countries of origin included Bolivia, Brazil, Cuba, India, and Indonesia.

Also, the health department reported 321 cases of Dengue fever among individuals who had traveled internationally, with over 180 cases related to travelers from Cuba and 14 from Puerto Rico. Additionally, 53 locally acquired Dengue cases were reported in Hillsborough, Miami-Dade (16), Pasco, and Brevard (35) counties.

Furthermore, 41 travel-related Malaria cases have been confirmed in Florida, 15 related to travel to Nigeria.

To alert visitors to these health risks, Alachua, Bay, Clay, Duval, Hillsborough, Lafayette, Leon, Pasco, and Pinellas counties are under a mosquito-borne illness advisory. Brevard, Escambia, and Miami-Dade Counties remain under a mosquito-borne illness alert.

However, the U.S. CDC has not issued a Travel Health Notice for Florida regarding these disease risks.

The first human cases of the Zika virus (ZIKV) were detected in 1952; researchers have been working to develop a preventive vaccine. 

This effort is essential as 31 countries and territories have reported cases of congenital microcephaly and other central nervous system malformations associated with Zika virus infection.

To address the unmet medical need, Valneva SE, a France-based specialty vaccine company, has been conducting phase 1 clinical trials, including its second-generation candidate.

Today, Valneva announced positive results of its current Phase 1 clinical trial (VLA1601-102) investigating the safety and immunogenicity of VLA1601, its second-generation adjuvanted inactivated vaccine candidate against Zika.

As of November 4, 2025, the Company confirmed that two doses of VLA1601 were immunogenic across all five treatment arms investigated (i.e., alumadjuvanted Low, Medium, and High antigen dose; Low with additional adjuvants).

The strongest immune response was observed in the double-adjuvant treatment arms (Low+alum+3M-052-AF and Low+alum+CpG1018) with statistically significantly higher neutralizing antibody titers (Geometric Mean Titers - GMTs) at Day 43 and Day 57 than in the single-adjuvant (alum) treatment arm.

And the immune response induced by the double-adjuvanted VLA1601 was successfully improved compared to the first-generation vaccine candidate, with higher peak seroconversion rates (>93% vs 86%) and peak Geometric Mean Fold Increase in titers (> 56-fold vs > 7-fold).

Juan Carlos Jaramillo, M.D., Chief Medical Officer of Valneva, commented in a press release, "We are pleased by the notable safety and immunogenicity results demonstrated for our Zika vaccine candidate and especially our double-adjuvantation results."

Should this vaccine development effort achieve US-FDA approval, international travelers, especially pregnant women, would be very interested in discussing immunization options with healthcare providers. Since 2013, 31 countries and territories, including Costa Rica and Puerto Rico, have reported cases of congenital microcephaly and other central nervous system malformations associated with Zika virus infection.

As of November 4, 2025, over 24,000 Zika cases and four related fatalities have been reported in the Region of the Americas this year.

According to the World Health Organization, mpox outbreaks remain a global health risk. Since mpox is a vaccine-preventable disease, access to the approved vaccine is essential.

To address this need, Bavarian Nordic A/S, a global vaccine company, recently issued the following clarification regarding the Health Emergency Preparedness and Response Authority (HERA) framework agreement.

The initial order for 750,000 doses of the MVA-BN (JYNNEOS) smallpox/mpox vaccine announced on October 31, 2025, will be delivered in 2026 and is the result of a new joint procurement contract by the European Commission through HERA.

This represents the second order received in 2025, following the earlier award of a contract option from the U. S. Biomedical Advanced Research and Development Authority in the U.S. Department of Health and Human Services, announced in May.

Bavarian Nordic anticipates additional orders for MVA-BN over the course of the following year.

As of November 3, 2025, in the United States, the JYNNEOS vaccine is commercailly available at various health clinics and pharmacies.

Chikungunya is a viral disease transmitted to humans through infected mosquitoes. The first known outbreak occurred in 1952. In the past year, 100 countries have reported chikungunya outbreaks to the the European Center for Disease Prevention and Control (ECDC).

In Italy, the National Institute of Health has reported 419 chikungunya cases in 2025, with approximately 370 confirmed as locally transmitted, primarily in the northern region of the country.

According to ECDC's Week 44 report on October 29, 2025, the largest cluster of cases is located in Carpi, San Prospero, Soliera, Novellara, Cavezzo, Modena, Nonantola, Correggio, Novi di Modena, and Cesenatico.

In the United States, the CDC says locally acquired chikungunya cases have not been reported since 2019.

However, as of late November 2025, the CDC confirmed 19 travel-related cases in states such as Florida, several of which were linked to visitors from Cuba.

The CDC currently recommends that international travelers visiting outbreak areas speak with a travel vaccine provider about immunization options. Approved chikungunya vaccines will be available at clinics and pharmacies in November 2025.