Vaccine News

When the U.S. Centers for Disease Control and Prevention (CDC) issued a Level 2 Travel Health Advisory regarding an outbreak of chikungunya in France's Réunion in February 2025, most public health experts did not expect an overwhelming epidemic.

As of April 12, 2025, Réunion Island has become the leading chikungunya outbreak in the world.

Since the beginning of 2025, 27,521 confirmed cases of this mosquito-transmitted disease have been reported.

More concerning is data from ARS Réunion last week. 

From March 24 to 30, 2025, there were 6,289 confirmed cases and 54 hospitalizations in Le Tampon (800 cases), Saint-Paul (900 cases), Saint-Denis (750 cases), and Saint-Pierre (600 cases). 

ARS Réunion says people can protect yourself by preventing mosquito bites, or participating in a free vaccination program.

The first phase of the 40,000 vaccination campaign has been launched with the single-dose IXCHIQ® vaccine. It is available for people aged 65 and over with comorbidities and who have not previously contracted chikungunya.

Over the last few years, most chikungunya cases in the U.S. have been related to returning international travelers from tropical and subtropical regions. Diagnosing chikungunya is challenging, as people may also have been infected with dengue or Zika.

According to the U.S. CDC, vaccination against chikungunya is recommended for adults and some adolescents traveling to a destination with a current chikungunya outbreak, such as Réunion.

A World Health Organization committee recently agreed that the risk of international spread of poliovirus continues to constitute a Public Health Emergency of International Concern.

During the 41st meeting of the Emergency Committee under the International Health Regulations, the Committee members unanimously recommended extending the Temporary Recommendations three months into July 2025.

On April 9, 2025, the WHO Director-General accepted the Committee’s assessment.

The Committee also called on national governments to prioritize polio eradication in their domestic funding allocations to ensure sustained progress toward eradication and appreciates the Kingdom of Saudi Arabia’s recent confirmation of its $500 million commitment to global polio eradication. 

Over the last three years, the nOPV2 polio vaccine has been administered about 1.1 billion times worldwide in various countries.

As of April 11, 2025, the U.S. CDC maintains a Global Measles Outbreak Travel Health Advisory that identifies 39 countries at risk for the spread of poliovirus.

In 2022, the United States was added to the list of polio-identified countries.

To reduce this significant health risk, the CDC says children and adults should be current on their routine polio vaccines, and that certain adult travelers visiting outbreak areas may get an inactivated polio vaccine (IPV) booster dose.

In the United States, IPV vaccination services are offered at travel clinics and pharmacies in 2025.

The New York State Department of Health recently issued a travel advisory for all New Yorkers, urging them to ensure they are fully vaccinated against measles before international travel or travel to an area in the U.S. experiencing an outbreak.

New York's advisory, published on April 2, 2025, listed Canada among the countries with increased measles cases.

As of March 22, 2025, six jurisdictions (Alberta, British Columbia, Manitoba, Ontario (548), Quebec, Saskatchewan) in Canada had reported 615 measles cases.

"Measles is more common in different places, and exposure during travel is something we need to consider. It's important that New Yorkers ensure they are up-to-date regarding being immunized against measles. In some cases, measles is as close as a car ride away," State Health Commissioner Dr. James McDonald said in a press release. 

"Measles can be a serious disease. It is not just a rash; it can cause pneumonia, hospitalization, and even death. Protect yourself and your family against measles and ensure you are up-to-date on immunization with the measles, mumps, and rubella (MMR) vaccine."

Currently, MMR vaccines are offered at clinics and pharmacies in the United States.

As of April 11, 2025, the U.S. CDC maintains a global Travel Health Advisory that lists various countries impacted by the ongoing measles outbreak.

While most malaria cases are detected in Africa, on the other side of the world, malaria outbreaks continue to be detected in South Korea.

According to a post on X, the South Korean government has recently confirmed locally acquired malaria cases and is taking immediate action.

On April 9, 2025, the Ministry of National Defense wrote, 'Recent outbreak of malaria patients among soldiers discharged from military service in border areas such as Paju, Gyeonggi Province, and Cheorwon, Gangwon Province.'

The Ministry of National Defense and the Korea Disease Control and Prevention Agency are working to achieve a 'Malaria-Free Republic of Korea' to eradicate malaria domestically by 2030.

The Joint establishment of the "Second Malaria Eradication Action Plan (2024-2028) includes:

• Free malaria diagnostic tests and treatment prescriptions for one year after discharge at 14 military hospitals nationwide.
• Free diagnostic testing is available two years after discharge at public health centers nationwide.

In 2024, the Agency issued malaria warnings for areas, including Seoul's Yangcheon and Gangseo districts. In 2023, over 719 cases of the mosquito-borne disease were confirmed.

According to the U.S. CDC, travelers going to areas of South Korea should take prescription medicine to prevent malaria. Depending on the medicine you take, you will need to start taking this medicine multiple days before your trip, as well as during and after your trip.

As of April 10, 2025, malaria vaccines are offered in Africa, but not South Korea or the United States.

The South Korean Ministry of Food and Drug Safety recently approved BARYTHRAX, an anthrax vaccine jointly developed by GC Biopharma and the Korea Disease Control and Prevention Agency.

Traditional anthrax vaccines are made by attenuating Bacillus anthracis or culturing non-pathogenic Bacillus anthracis, which may contain residual toxin components. BARYTHRAX removes this risk and improves vaccine safety. 

BARYTHRAX utilizes protective antigen (PA) proteins produced through genetic recombination techniques. With an anthrax infection, PA is a gateway for 2 Bacillus anthracis toxins, lethal factor and edema factor, to enter host cells.

BARYTHRAX vaccination can train and stimulate an immune response to neutralize anthrax by utilizing PA proteins.

Eun-chul Huh, President and CEO of GC Biopharma, commented in a press release on April 9, 2025, "This achievement underscores our commitment to localizing critical medicines for public health and national security. GC Biopharma will continue leading efforts to ensure stable supplies of essential medical products, as we have been doing with other vaccines and blood products since our founding."

Anthrax, caused by Bacillus anthracis, is a class-1 infectious disease capable of surviving extreme conditions and spreading easily through airborne transmission. If untreated, its fatality rate can reach up to 97%, making it a significant threat as a potential biological weapon.

The MFDS's approval, supported by GC Biopharma's production capacity, will pave the way for the company to supply Korea's essential anthrax vaccine reserve.

In the United States, very few people get anthrax from infected animals or contaminated animal products. The U.S. CDC says The type of illness a person develops depends on how anthrax enters the body: through the skin, lungs, or gastrointestinal system.

Getting a vaccine or taking certain antibiotics after exposure to anthrax can help prevent illness.

As of April 9, 2025, the U.S. FDA has approved anthrax vaccines for those at risk of exposure to anthrax bacteria.

For example, CYFENDUS™ is a combination of BioThrax® (anthrax vaccine adsorbed) and CPG 7909, a synthetic short DNA sequence as a vaccine adjuvant.

Mono County Public Health has confirmed a third fatality due to Hantavirus in the Town of Mammoth Lakes, a favorite outdoor destination for vacationers in Northeast California.

As of April 3, 2025, Mono County has recorded 27 cases since it was first reported here in 1993, the most in California. Twenty-one of these infections affected county residents, and six occurred among visitors who were infected in Mono. In 

As of 2022, 864 cases of Hantavirus disease were reported in the United States.

According to the U.S. CDC, Hantavirus is a serious and often fatal illness contracted through infected deer mouse droppings, urine, or saliva. It most commonly occurs in the late spring or summer.

“A third case of Hantavirus Pulmonary Syndrome (in 2025), each of which has been fatal, is tragic and alarming,” said Dr. Tom Boo, Mono County Public Health Officer, in a press release.

“We don’t have a clear sense of where this young adult may have contracted the virus. The home had no evidence of mouse activity. We observed some mice in the workplace, which is not unusual for indoor spaces this time of year in Mammoth Lakes.

We haven't identified any other activities in the weeks before illness that would have increased this person's exposure to mice or their droppings.

We’ve been aware of this suspected case for weeks, but obtaining testing has taken time. The occurrence of three cases in a short period has me worried, especially this early in the year.

We’ve gone about a month without additional suspect cases, but remain concerned about the increased activity.

We believe deer mouse numbers are high this year in Mammoth (Eastern Sierra). An increase in indoor mice elevates the risk of Hantavirus exposure.

As far as we know, none of these deceased individuals engaged in activities typically associated with exposure, such as cleaning out poorly ventilated indoor areas or outbuildings with a lot of mouse waste. Instead, these folks may have been exposed during normal daily activities in the home or the workplace.

Many of us encounter deer mice daily, and there is some risk. We should pay attention to the presence of mice and be careful around their waste,” stated Dr. Boo.

Without a preventive vaccine available in 2025, the county says to avoid eating food that may have been contaminated by rodents and always wash your hands thoroughly after any potential exposure.

The Pan American Health Organization (PAHO) recently updated its Dengue fever outbreak data dashboard, highlighting the continued surge of cases in 2025.

Within the Americas, the Federative Republic of Brazil's state of São Paulo is on track to exceed last year's record numbers.

As of April 8, 2025, São Paulo has reported approximately 522,000 dengue cases and 390 related fatalities, with an additional 475 deaths currently under investigation by the health ministry.

For all of 2024, over 9.6 million dengue cases and 5,441 related fatalities were reported throughout Brazil.

While Dengue has become endemic in the U.S. territories of Puerto Rico and the U.S. Virgin Islands, most cases in the United States are travel-related.

The U.S. Centers for Disease Control and Prevention (CDC) reported on April 2, 2025, that 1,346 travel-related Dengue cases and one local case have been reported in 30 jurisdictions this year.

Most of these cases were identified in southern Florida.

With over 6 million people visiting Brazil in 2024, and many international travelers returning to the U.S., identifying Dengue infections has become a challenge.

To offer updated guidance on Dengue testing, the CDC recently issued a Health Alert Network (HAN) Health Update to provide additional information to healthcare providers about the ongoing risk of dengue virus infections and updates to testing recommendations in the United States.

The CDC urges healthcare providers to continue taking steps to prevent, detect, diagnose, and respond to Dengue, as described in the June 2024 HAN Health Advisory (CDCHAN-00511).

Currently, the CDC does not recommend any Dengue vaccine in the U.S. However, second-generation Dengue vaccines are available in about 40 countries.