Vaccine News

As millions of international travelers visit countries in South America, a mosquito-transmitted killer is devastating the Republic of Colombia in 2025.

As of July 23, 2025, the country has confirmed 103 cases of Yellow fever, resulting in 37 deaths, a staggering 36% fatality rate that underscores the virus's lethal potential.

The Pan American Health Organization (PAHO) previously sounded the alarm with a regional alert, warning that Yellow fever continues to pose a grave threat across the Americas.

While the disease is preventable through vaccination, gaps in immunization have allowed it to surge in Colombia's rural and forested areas.

At the epicenter of the crisis are the municipalities of Cunday and Rioblanco in the Tolima Department, which is unusual, given their high altitude.

Tolima's rural terrain has historically been a breeding ground for the virus, but officials are determined to contain it.

Katherine Rengifo, Tolima's Secretary of Health, highlighted the establishment of a Unified Command Post, personally led by the governor, to oversee containment efforts.

"Every time there is an unvaccinated resident of Tolima or a visitor, there is a risk of transmission," Rengifo warned in a press release.

"All efforts by the Departmental Government, the Ministry of Health, the National Institute of Health, and the Superintendency are focused on containing this outbreak and, above all, preventing its urbanization, which is the greatest risk we face."

"Urbanization, the spread of yellow fever into densely populated cities via the Aedes aegypti mosquito, could ignite a public health catastrophe, potentially overwhelming healthcare systems and leading to widespread panic."

To date, Tolima has rolled out over 728,000 doses of the yellow fever vaccine, achieving 57% coverage in a region that, until recently, lacked a robust immunization program.

This rapid scale-up is a testament to the collaborative push involving national and local health entities.

Unfortunately, the spotlight turned to Villarrica and Cunday, where teams are enforcing an "epidemiological lockdown"—a targeted approach combining surveillance, mosquito control, and mass vaccination drives.

Rengifo emphasized that the goal is to reach 95% vaccination rates to create a protective shield around vulnerable populations.

"The vaccine is free, safe, and saves lives," Rengifo added.

While Colombia's battle against yellow fever is far from over, the PAHO's latest data indicate that five other countries continue to report cases and fatalities in 2025.

Throughout the Americas, 134 fatal cases have been confirmed this year. 

In addition to the PAHO's warning, the U.S. CDC has issued a Travel Health Advisory for the Americas, recommending Yellow fever vaccination for specific areas, such as in Colombia.

In the United States, the YF-VAX vaccine is expected to be commercially available at travel clinics and pharmacies in late July 2025.

During the winter of 2024-2025, cases of a highly contagious stomach bug characterized by sudden vomiting and diarrhea surged. Nicknamed the "Ferrari of viruses" for its rapid spread, norovirus is also known for its ability to quickly infect cruise ships.

The U.S. Centers for Disease Control and Prevention (CDC) cruise ship inspections for illness are on pace to set new records in 2025.

As of July 2025, the CDC's Vessel Sanitation Program had reported 18 gastrointestinal illnesses on cruise ships this year, most classified as norovirus.

A University of Surrey–led research team identified cruise ship dining areas as priorities for preventing norovirus outbreaks.

However, according to those who study it, the virus hasn't received the attention it deserves, wrote Kate Schweitzer in an article published by JAMA on July 25, 2025.

From a prevention perspective, scientists have taken several approaches to developing a norovirus vaccine. Unfortunately, no candidate vaccine has been approved yet.

Schweitzer's unedited article is posted at this JAMA link.

Since the beginning of 2025, three European countries have reported human cases of West Nile virus infections: Greece, Romania, and Italy.

According to Italy's National Institute of Health, 10 confirmed human cases of West Nile virus have been reported since the beginning of 2025.

As of July 20, 2025, seven of these mosquito-transmitted cases had been reported from the Lazio region, specifically from Latina, Italy's second most populous region, with over 5 million residents.

Throughout 2024, twenty WNV-related deaths were recorded in Italy.

In the United States, 1,466 WVN cases were reported in 2024, with over 1,000 cases involving the nervous system. Most WNV cases are reported in the southwest states.

As of July 24, 2025, WNV vaccine candidates continue to be tested in clinical research for prevention purposes. However, none have been approved for use in humans.

The ARS Auvergne-Rhône-Alpes states that most dengue cases reported in mainland France involve international travelers who were infected with the mosquito-transmitted virus while visiting a tropical region.

If people return to France infected, dengue symptoms occur on average within 4 to 7 days after the infective bite. These are considered imported cases.

However, recent reports suggest that a local outbreak may occur in July 2025.

Approximately 50 kilometers southwest of Lyon, France, Saint-Chamond, in the Auvergne-Rhône-Alpes region, has confirmed a second locally acquired case of Dengue as of July 15, 2025.

'At this stage, it is not possible to establish a link with the first indigenous case identified in Saint-Chamond, as the investigations are still ongoing,' wrote ARS Auvergne-Rhône-Alpes.

An entomological survey conducted on July 18, 2025, confirmed the presence of tiger mosquitoes in areas frequented by the infected person and informed residents of an adulticide treatment. These mosquitoes carry dengue viruses.

Around one hundred homes in the affected area have been informed.

As of July 23, 2025, Sante Publique France reported a total of four locally acquired cases of Dengue for 2025.

In 2024, France reported 82 locally transmitted cases of dengue fever. Outbreaks were identified in the Provence-Alpes-Côte d'Azur, Occitanie, and Auvergne-Rhône-Alpes regions.

The World Health Organization has classified Dengue as a grade 3 emergency, with an estimated 4 billion people at risk in approximately 110 countries, including areas within the United States, such as Florida and Puerto Rico. 

While numerous countries offer Dengue vaccinations, only Puerto Rico continues to provide a first-generation vaccine to children.

Note: This article was updated on July 24, 2025.

The WHO Director-General recently determined that the upsurge of mpox cases in Africa continues to meet the criteria of a public health emergency of international concern and issued temporary recommendations to States Parties as of July 10, 2025.

The first human case of mpox was recorded in 1970 in the Democratic Republic of the Congo, which has subsequently spread to other central and western African countries. 

According to the U.S. Centers for Disease Control and Prevention (CDC), outbreaks of clade II mpox have been reported in Liberia and Sierra Leone, where mpox is endemic.

The CDC's updated Level 2 - Practice Enhanced Precautions, Travel Health Advisory states that, unlike the ongoing global clade II mpox outbreak, which began in May 2022, these outbreaks have affected males and females approximately equally. 

Furthermore, person-to-person transmission has occurred during this outbreak, including through sexual or other intimate contact.

Previously, the Ministry of Health in Cameroon confirmed the first case of mpox (Clade I) in a child from Ayos district, as of July 9, 2025.

The CDC recommends mpox vaccination (JYNNEOS®, MVA-BN®, IMVAMUNE®) for travelers to Liberia and Sierra Leone.

This advice is essential as millions of international travelers are visiting Africa.

According to the World Tourism Barometer from UN Tourism, Africa attracted approximately 74 million tourists in 2024.

As the respiratory syncytial virus (RSV) season expands in the state of Florida, the most significant US real-world study of a single-dose long-acting antibody designed to help prevent RSV lower respiratory tract disease in infants successfully met both of its co-primary endpoints.

The full results from the "Effectiveness of nirsevimab against RSV and RSV-related events in infants" study have been published in PEDIATRICS®, an official journal of the American Academy of Pediatrics, on July 22, 2025.

Ayman Chit, Head of North America Medical, Vaccines, Sanofi, commented in a press release, "These results support BEYFORTUS (nirsevimab) as a groundbreaking advancement in infant RSV disease prevention."

"With more than 40 real-world evidence studies to date, this latest study further strengthens the well-established body of data that shows that BEYFORTUS protects against RSV disease to help safeguard the health of all babies, regardless of whether they are born before or during the RSV season."

According to the Florida Department of Health, RSV is a common respiratory virus that typically causes mild, cold-like symptoms. Young children and older adults, especially those with certain underlying health conditions, are at higher risk for severe illness from RSV.

Florida’s RSV season is longer than that of the rest of the nation and exhibits distinct regional patterns. For this reason, the state is broken up into five RSV regions, each with its own RSV season.

With an unexpected number of chikungunya outbreaks reported in the Region of the Americas in 2025, Canada is taking action to ensure an ample supply of vaccines available.

In the past 20 years, the mosquito-transmitted chikungunya virus has emerged across many popular travel destinations.

Bavarian Nordic A/S announced today that Health Canada has accepted for review the Company's application for licensure of the single-dose, virus-like particle (VLP) chikungunya vaccine candidate, CHIKV VLP, for immunization to prevent disease caused by chikungunya virus infection in individuals 12 years of age and older.

The Directorate's acceptance of the application screening confirms that the New Drug Submission is complete, initiating a standard review procedure that may support approval of the vaccine in the first half of 2026.

Paul Chaplin, President and CEO of Bavarian Nordic, stated in a press release on July 22, 2025, "Pending approval, this vaccine will further strengthen our offering for Canadians seeking protection against serious diseases when traveling the world."

The VLP vaccine was approved by the U.S. Food and Drug Administration, the European Commission, and the United Kingdom in May 2025 under the trade name VIMKUNYA®.

In the U.S., VIMKUNYA is commercially available at clinics and pharmacies.