Vaccine News

International travelers visiting countries in Africa in 2025 should be aware of the health risks associated with the ongoing cholera outbreak.

Cholera is a potentially fatal infection that causes severe diarrhea but can be prevented with vaccination.

While cholera is no longer a health risk in the United Kingdom (UK), it is sometimes reported in returning travellers from three WHO regions.

For example, the UK's Travel Health Pro reported on March 7, 2025, that four cases of cholera (toxigenic Vibrio cholerae serogroup O1) were locally diagnosed in mid-February 2025.

Three UK travellers were recently diagnosed with cholera after visiting the Federal Democratic Republic of Ethiopia.

A fourth UK cholera case did not travel but reported consuming water from Ethiopia by one of the returned travellers before experiencing symptoms.

Ethiopia is just one of 22 areas the WHO currently identifies as a risk for cholera.

A cholera vaccine can be considered for travellers departing from the UK following a full risk assessment and those with limited access to safe water and/or underlying health problems.

According to the U.S. CDC, cholera remains a global health risk.

And when leaving the United States in March 2025, the U.S. CDC recommends that travelers speak with a travel vaccine expert about cholera prevention options. Following increased production, cholera vaccines have become more available this year.

Brazil's Ministry of Health (MOH) has been reporting data on the locations of Chikungunya patients for the past three years.

As of March 11, 2025, the MOH reported that most of the 40,000 Chikungunya cases reported this year were found in Sao Paulo (5,714) and Minus Gerias (5,120).

Last year, there were about 265,000 Chikungunya cases and 231 related fatalities in Brazil, located in similar states.

The Chikungunya virus is transmitted to people through the bite of an infected mosquito of the Aedes spp., which are found at beaches and in mountains below seven thousand feet in elevation. 

While the U.S. CDC has not issued a Travel Health Advisory regarding Brazil's ongoing Chikungunya outbreak, it writes, 'There has been evidence of chikungunya virus transmission in Brazil within the last five years.'

Chikungunya vaccination may be considered for seniors, especially those with underlying medical conditions, who may spend at least two weeks (cumulative time) in indoor or outdoor areas where mosquitoes are present in Brazil, or visitors planning to stay in Brazil for a cumulative period of six months or more.

Before departing for Brazil, most travel clinics and pharmacies in the United States offer the U.S. FDA-approved chikungunya vaccine. Valneva SE's IXCHIQ® vaccine has been found safe and effective in various studies.

The Ministry of Health for the State of São Paulo recently confirmed its first patient infected with Mpox Clade 1b. The infection was confirmed in early March 2025 in an adult woman in the Metropolitan Region of São Paulo.

According to the media statement of March 10, 2025, she is expected to be discharged next week.

The patient had not traveled to outbreak areas in Africa but had contact with individuals from the Democratic Republic of Congo, where the virus is endemic. 

"No secondary cases have been identified as yet. The municipal surveillance team is keeping track of possible contacts," the Ministry's Edjalma Borg statement reads.

Mpox has been considered endemic in Africa since the 1970s.

In May 2022, Mpox Clade 2 cases were detected in numerous countries, including the United States. Since July 2024, cases of Clade 1b have been identified in several countries, such as England.

According to various studies, Mpox vaccinations help prevent severe disease.

Located on Brazil's northern coast, Marajó Island has been reporting yellow fever outbreaks for two decades. Recently, a severe outbreak has been confirmed.

As of March 7, 2025, Brazil's Ministry of Health confirmed 37 cases and five related deaths from the mosquito-transmitted yellow fever disease in the Belém area of Pará this year.

This area has about 500,000 residents and welcomes thousands of eco-friendly tourists annually.

Yellow fever is an acute infectious febrile disease that can be prevented with a vaccine. It progresses rapidly and has variable severity, and in its most severe forms, it can be fatal.

Locally acquired YF cases are seldom reported in the United States, but travel-related cases were reported in 2024.

Vaccination has been the primary prevention strategy in Brazil since 2014. Currently, yellow fever (YF) vaccination coverage is 72.6%.

YF vaccines are free of charge to the entire population. Since April 2017, Brazil has adopted a single-dose regimen throughout life, following the World Health Organization's (WHO) recommendations.

The Ministry of Health sent 442,400 doses to Pará in 2025 alone to reinforce YF immunization.

The WHO, U.S. CDC, and Brazil have issued vaccination requirements to enter various countries in the Region of the Americas. YF vaccination services are offered at certified travel clinics and pharmacies in the U.S.

With about 90% of the world's malaria cases reported in Africa, one country is taking action to curtail the impact of this mosquito-transmitted disease.

On March 7, 2025, Uganda's Minister of Health, Hon. Dr Jane Ruth Aceng Ocero, approved the distribution of 2.278 million doses of malaria vaccines to 105 districts. This effort is a significant milestone in the country's fight against malaria.

Malaria remains the leading cause of illness and death of young children in Uganda. The malaria vaccine will be introduced into the routine immunisation schedule in April 2025, targeting children below two years old.

Speaking at the flag-off event, Dr Aceng emphasised in a press release the government's commitment to strengthening disease prevention efforts and building resilient health systems." Introducing the malaria vaccine in Uganda is a historic step forward in our fight against this deadly disease."

"With the support of Gavi, UNICEF and other partners, we are ensuring that every eligible child has access to this life-saving intervention," the Minister stated.

The World Health Organization (WHO) recommends malaria vaccinations to prevent P. falciparum malaria in children living in malaria-endemic areas. As of March 10, 2025, the WHO and the African CDC recommend Mosquirix™ and R21 / Matrix-M™ vaccines for travelers visiting malaria-endemic countries.

Currently, malaria vaccines are not offered in the United States.

The Philippines's most populous city, Quezon City, has been a well-known hub for business activities and tourism as the city of stars in Asia. Unfortunately, it has become a hot spot for the mosquito-transmitted Dengue virus in 2025.

From January to March 9, 2025, the City Epidemiology and Surveillance Division of Quezon City recorded 3,608 Dengue cases and 12 related fatalities, a significant (300%) increase from 2024.

Overall, Quezon City has about 3 million residents and is 12 miles northeast of the capital city of Manila. Most of the Dengue cases have been reported in District #2 this year.

Previously, the City's Health Department declared a Dengue outbreak.

“Our declaration of a dengue outbreak ensures that we are on top of the situation, and we are doing everything we can to protect our residents from this deadly disease, especially our children,” Mayor Joy Belmonte said in a February 27, 2025, press release.

Recently, the Global Dengue Travel Health Advisory, updated by the U.S. CDC, highlighted the Philippines, saying that this disease is a year-round risk in many parts of the world, including the United States.

As of March 2025, there have been 893 Dengue cases reported in 23 U.S. jurisdictions this year, led by Florida.

While Dengue vaccines are no longer available in the U.S., the CDC recommends discussing immunization options with a travel vaccine expert.

Before visiting the Philippines, the CDC also suggests that future travelers discuss chikungunya, cholera, Japanese encephalitis, and malaria prevention options. And under International Health Regulations, proof of vaccination against yellow fever is required for certain travelers arriving from countries with a risk of yellow fever transmission in 2025.

Since the recent Sudan virus disease (SUDV) outbreak was declared in the Republic of Uganda in late January 2025, a total of 14 cases, including four related fatalities, a case fatality ratio of 29%, have been reported.

As of March 5, 2025, 192 new contacts have been identified and are under follow-up in Kampala, Ntoroko, and Wakiso.

SUDV was first identified in Sudan in June 1976. This is the eighth outbreak, five in Uganda and three in Sudan.

According to the WHO's Disease Outbreak News (558) published on March 8, 2025, the Ministry of Health (MOH) stated, 'the risk of potential serious public health impact is high.' The MoH has scaled up its case management strategy to ensure sufficient capacities to provide care for all suspected and confirmed cases in all hot spots

The WHO says SVDV is a severe disease belonging to the same family as Ebola virus disease (EVD).

While several promising candidate therapeutics are currently advancing through clinical development, no licensed treatment is yet available to effectively address potential future outbreaks of EVD caused by the Sudan virus species.

A range of candidate SUDV vaccines and therapeutics are under development.

Since 2020, one vaccine and two candidate therapeutics (a monoclonal antibody and an antiviral) have been recommended. They are available in Uganda and are being assessed through randomized clinical trial protocols.

Two vaccines licensed against Zaire EVD will not provide cross-protection against SUDV.

Currently, the WHO advises against travel and/or trade restrictions to Uganda.

However, the U.S. CDC has issued a Travel Health Advisory, Level 2, for Unganda in February 2025. 

The CDC says visitors to Uganda should avoid contact with sick people who have symptoms, such as fever, muscle pain, and rash, or contact with blood and other body fluids and semen from men who have recovered from EVD until testing shows that the virus is no longer in the semen.