Vaccine News

French Polynesia, located in the southwest Pacific Ocean, has been a dream vacation destination for decades.

However, these islands are also home to dengue fever, which is transmitted by the bite of infected mosquitoes.

According to Bulletin de surveillance sanitaire de Polynésie française n°34, published on September 2, 2025, there were 22 new dengue cases (19 confirmed last week.

And the blue alert for DENV-1 remains in effect.

Since November 2023, a total of 2,577 cases have been recorded.

To alert international travelers of this health risk, the U.S. CDC's Travel Health Advisory issued on August 21, 2025, included French Polynesia.

The CDC identified the island groups of the Society Islands (Tahiti, Moorea, and Bora Bora), the Marquesas Islands (Hiva Oa and Ua Huka), and the Austral Islands (Tubuai and Rurutu).

The CDC reported that these countries are experiencing higher-than-usual numbers of cases and have identified a higher-than-expected number of dengue cases among U.S. travelers returning from those countries. 

While a second-generation dengue vaccine is available in various countries, it is not offered in the USA.

Fortunately, several dengue vaccine candidates are conducting late-stage research focused on preventing all four virus types from infecting people.

The World Health Organization (WHO) recently confirmed that the global cholera situation continues to deteriorate in 2025.

Cholera is resurging in several countries, with some that had not reported substantial case numbers in years.

Since January and through August 17, 2025, the WHO has reported a total of 4,738 cholera/Acute Watery Diarrhoea-related fatalities from 31 countries, with six of the 31 countries reporting case fatality rates (CFR) above 1%.

For example, suspected cholera cases have been reported from two provinces of the Republic of Chad. Among these, Chokoyane is the most affected area, accounting for 541 cases and 25 deaths, with a district-specific CFR of 4.6%.

While Cholera is an acute diarrheal infection caused by consuming food or water contaminated with the bacterium Vibrio cholerae, primarily associated with poor sanitation and limited access to safe water, it can be prevented with vaccination.

As of September 5, 2025, the U.S. CDC's Travel Health Advisories for these countries advise cholera vaccination before departing abroad. Most cholera cases diagnosed in the U.S. are related to international travel.

In the U.S., Vaxchora® (CVD 103-HgR) is the only U.S. FDA-approved vaccine available at travel clinics and pharmacies.

The U.S. Centers for Disease Control and Prevention (CDC) today announced an update to its Level 2 Travel Health Advisory for the Republic of Colombia, due to a yellow fever outbreak.

On September 3, 2025, the CDC reported an increase in cases in new areas in the South American country.

In a Facebook post, the Health Ministry reported that between 2024 and 2025, 132 yellow fever (YF) cases were registered, resulting in 57 deaths, in the following Colombian departments: Tolima, Huila, Cauca, Nariño, Putumayo, Caldas, Meta, Vaupés, Guaviare, and Caquetá.

The CDC recommends that travelers to these newly affected areas get vaccinated at least 10 days before traveling abroad, as yellow fever is a severe viral disease.

Last year, the Colombian government declared a nationwide health emergency to alert residents and visitors to the situation.

Colombia welcomed over 6.5 million international visitors.

Recently, the U.S. Embassy in Bogota issued an alert stating visitors should reconsider travel to the Valle del Cauca Department due to civil unrest.

As of September 2025, YF is a vaccine-preventable disease, and proof of vaccination is required to enter various countries, including Colombia. 

A booster dose may be given to eligible travelers or those who received their last dose of the YF vaccine at least 10 years prior and will be in a higher-risk setting, according to the CDC.

"With yellow fever cases rising in Colombia, the CDC has expanded the list of areas where vaccination is now recommended. We're seeing a similar trend in parts of Peru and Bolivia, too," commented Jeri Beales, MSN, RN, BS.

This isn't a mosquito-borne virus to take lightly—yellow fever can be deadly, with fatality rates as high as 60% in severe cases."

"If you're planning a trip to Colombia, consult with a travel health provider about getting vaccinated. It's highly effective and usually offers lifelong protection. Still, it's only available at certified clinics, so schedule ahead—ideally a few weeks before you leave to give the vaccine time to create a robust immune response so you're fully protected before arriving," added Beales, vaccination leader at Destination Health, located in the greater Boston, MA, area.

In the United States, the YF-VAX vaccine is commercailly offered at travel vaccination retailers.

Note - vaccine expert insight added on September 6, 2025.

The Communicable Diseases Agency of the Republic of Singapore has reported a total of 21 chikungunya cases this year.

As of August 28, 2025, this number has already surpassed the total recorded for all of 2024, which was 15 cases.

The increase began in May 2025, primarily due to travelers returning from areas affected by the chikungunya outbreak in China's Guangdong Province and several French Territories in the western Indian Ocean.

In 2024, this sovereign island country and city-state in Southeast Asia welcomed approximately 16.5 million international tourists, representing a 20% increase from the previous year.

In early August, Professor Ooi Eng Eong from Duke-NUS Medical School explained to the media that although chikungunya is less deadly than dengue, it can be debilitating. Chronic joint discomfort can limit physical activity and impact overall quality of life.

Although the U.S. CDC has not issued a Travel Health Advisory for chikungunya related to Singapore, the UK's Travel Health Pro indicates that there is a risk of chikungunya in this country.

As of September 3, 2025, the UK recommends that international travelers take precautions to avoid mosquito bites, especially during daytime hours.

Additionally, vaccination may be considered for individuals aged 12 years and older who meet specific eligibility criteria.

In the United States, the FDA has approved a chikungunya vaccine, which is available at travel clinics and pharmacies.

According to the WHO's Multi-country External Situation Report #57, published on August 28, 2025, all clades of the monkeypox virus (MPXV) continue to circulate in several countries.

The WHO writes that 'when mpox outbreaks are not rapidly contained and human-to-human transmission is not interrupted, they continue to pose a risk of sustained community transmission.'

In July 2025, 47 countries reported a total of 3,924 confirmed cases, including 30 deaths (case fatality ratio 0.8%).

China, Germany, Türkiye, and the United Kingdom have reported additional cases of mpox due to clade Ib MPXV since the last situation report.

These new cases have been linked to international travel.

On August 20, 2025, the WHO Director-General extended the standing recommendations for mpox until August 2026 to further prevent or reduce the international spread of mpox, as well as its impact on health.

Both the WHO and the U.S. Centers for Disease Control and Prevention (CDC) recommend receiving your first mpox vaccine at least 6 weeks before travel. After completing your first and second vaccine doses, which are given 4 weeks apart, it takes about two more weeks to get the best protection against mpox.

The majority of U.S. cases of clade II mpox continue to be reported in people who are not vaccinated or have received only one dose.

Several cases have recently been tied back to an outbreak in Sierra Leone, Liberia, and other West African countries.

The CDC suggests that whether or not you've been vaccinated (JYNNEOS®, MVA-BN®, IMVAMUNE®), you continue to reduce your risk of getting mpox.

The Dominican Republic Ministry of Health recently announced that the Caribbean island country had reduced dengue fever cases by over 85%.

As of Epidemiological Week 33, the total for 2025 is now 174 dengue cases, a significant improvement from last year's outbreak..

During 2024, 1,110 dengue cases were recorded in the same period.

The Health Ministry stated the decrease is attributed to the effectiveness of the national relaunch of the "Let's Beat Dengue" campaign, which carries the slogan "Eliminate, Clean, and Cover."

As part of the campaign, educational workshops, community operations to eliminate breeding sites, targeted fumigations, junk removal, distribution of informational materials, and larvicide distribution were implemented.

Dominican Republic's Minister of Health, Víctor Atallah, highlighted in a media release posted at the end of August 2025, that these prevention initiatives have positioned the country as a leader in disease control in the Region of the Americas, where dengue virus-transmitting mosquitoes have caused significant harm over the past few years.

“We have demonstrated that prevention works. The country today shows encouraging figures that reflect the dedication of our personnel and the commitment to protecting the health of the Dominican people."

"Now we will redouble our efforts to sustain and expand this success, and continue winning the battle against dengue," stated Atallah.

In addition to dengue, this vacationer's favorite destination continues to battle two other mosquito-borne diseases, chikungunya and malaria.

As of September 2, 2025, the U.S. CDC recommends chikungunya vaccination for at-risk travelers visiting areas with outbreaks; however, vaccines for dengue and malaria are not available in the USA.

The U.S. government has recently issued travel alerts regarding visits to the Plurinational State of Bolivia in 2025.

As of August 31, 2025, the U.S. CDC included Bolivia in two recent Travel Health Advisories: one for measles outbreaks and another for yellow fever. 

Additionally, Bolivia is reporting an unusual number of mosquito-transmitted chikungunya fever cases in 2025.

The Pan American Health Organization's latest data indicate that Bolivia trails just Brazil in the number of chikungunya cases (5,159) and deaths (4) in the Americas in 2025.

Oropouche virus and Zika diseases are also emerging risks in Bolivia.

If you plan to visit Bolivia, the CDC has confirmed that U.S. FDA-approved travel vaccines are available for these diseases at various retailers in the USA.

From a safety perspective, the U.S. Department fo State's travel advisory for Bolivia says visitors should exercise increased caution in Bolivia due to civil unrest. Some areas have an increased risk.

For example, the State Department advises against visiting the Chapare region due to crime.

If you do visit this area, the local embassy recommends enrolling in the Smart Traveler Enrollment Program to receive digital alerts and make it easier to locate you in an emergency.