Vaccine News

While most hikers and campers await the results of a Phase 3 clinical trial of the most advanced Lyme disease vaccine candidate, The Lancet Infectious Diseases recently published an article highlighting very positive data from the Phase 2 study.

On April 25, 2025, results from the NCT04801420 study confirm the previously observed safety and immunogenicity profiles of VLA15 in adults and extend them to children aged five years and older, as well as adolescents.

Additionally, the greater immunogenicity of VLA15 among children and adolescents might translate to increased flexibility in the real-world clinical setting.

According to Vaneva SE and Pfizer Inc., VLA15 is an investigational multivalent protein subunit vaccine that utilizes an established mechanism of action for a Lyme disease vaccine, targeting the outer surface protein A (OspA) of Borrelia burgdorferi, the bacterium that causes Lyme disease.

OspA is a surface protein expressed by the bacteria when present in a tick. Blocking OspA inhibits the bacterium’s ability to leave the tick and infect humans.

The vaccine candidate covers the six most prevalent OspA serotypes expressed by the Borrelia burgdorferi sensu lato species in North America and Europe.

Lyme disease, if left untreated, can cause serious chronic complications affecting the skin, joints, heart, or nervous system. 

According to various health agencies, the medical need for vaccination against Lyme disease is steadily increasing as the geographic footprint of the disease widens in the United States and Europe.

Throughout Europe, the bacteria are only transmitted by the bites of the ticks Ixodes ricinus and I. persulcatus. In the most affected regions, tick infection rates may exceed 10%. These areas are primarily located in central Europe.

However, the ECDC says in recent years, the spread of infected ticks has extended toward northern latitudes, including Scandinavia.

In the United Kingdom, the South of England and the Scottish Highlands have been earmarked by the government as high-risk areas for Lyme disease in 2025. Annually, the UK Health Security Agency reports about 1,500 laboratory-confirmed cases of Lyme disease.

With millions of people returning to the woods and mountains this summer, analysts say there is significant pent-up demand for an effective Lyme disease vaccine.

Once again, research affirms that healthcare professionals remain the most trusted source of information (73%) and can significantly influence disease prevention efforts, such as vaccination.

A University of Texas Southwestern Medical Center survey published on April 24, 2025, found that 58% of adults say they would be willing to be vaccinated against mpox if their healthcare provider recommended it.

This data represents a 12% increase since 2022.

According to an article published in Vaccine (Volume 56, May 22, 2025, 127141), self-reported knowledge of mpox (40%), as well as perceived self-efficacy (55%) and mean risk perception (3.2), have also increased since the 2022 survey.

Respondents from the Health and Human Services Region 1 (CT, ME, MA, NH, RI, VT) were the least likely to receive the vaccine, even when recommended to do so.

These results highlight the need for ongoing education among adults to improve awareness of and vaccination intention for the mpox vaccine.

The consistently high degrees of trust placed in healthcare professionals and officials should guide future communications about mpox and other infectious diseases, and reinforce the importance of leveraging trusted sources to share essential public health information, wrote these researchers.

In May 2022, an unprecedented global outbreak of mpox Clade IIb prompted the World Health Organization (WHO) to declare a Public Health Emergency of International Concern. Since then, mpox cases, including Clade 1, have been reported in more than 126 WHO Member States.

As of April 28, 2025, mpox vaccination (JYNNEOS) services are commercially offered throughout the United States.

When the U.S. Centers for Disease Control and Prevention (CDC) reissued a Global Polio Alert on April 22, 2025, it identified 38 countries, indicating that the spread of poliovirus remains a public health emergency.

But the CDC did not mention Israel, but did include its neighbor, Gaza.

According to the Ministry of Health's Central Virus Laboratory, on April 24, 2025, poliovirus was detected in environmental samples in central Israel and the Jerusalem area, which has about 1 million residents. 

However, as of April 27, 2025, Israel's ministry had not reported any recent polio cases.

In March 2023, several children were confirmed with polio in Israel.

Over the past years, Israel has offered polio vaccination services throughout the country. But, as of March 2025, the administration of the live attenuated polio vaccine (oral) has been discontinued. 

In its place, the inactivated polio vaccine is now offered. This is the same polio vaccine provided in the United States.

Most African countries have switched to the nOPV2 polio vaccine over the past three years.

The CDC recommends that before travel to any listed destination, adults who previously completed the routine polio vaccine series may receive a single, lifetime booster dose of polio vaccine, which will extend their protection from this severe disease.

The Republic of Uganda today announced the end of the current Sudan Ebolavirus disease (SVD) outbreak, less than three months after the virus was confirmed in the capital Kampala. 

This strain of Ebolaviris often causes a severe, fatal illness in infected people.

As of April 26, 2025, during this outbreak, 14 SVD cases, including 12 confirmed and two probable cases, had been reported.

And four deaths, two confirmed and two probable, occurred.

"This outbreak challenged us in new ways. It touched both urban and rural communities across the country and unfolded against the backdrop of significant global funding constraints," said Dr Chikwe Ihekweazu, Acting WHO Regional Director for Africa, in a press release on April 26, 2025.

"The response demonstrated Uganda's long-standing leadership in tackling public health emergencies. As WHO, we are extremely proud to have supported these efforts every step of the way."

Despite the absence of licensed countermeasures against this species of Ebolavirus, Sudan candidate vaccines are in various phases of clinical trials. Within four days of the government's declaration of the outbreak, a randomized clinical trial for vaccine safety and efficacy using the ring vaccination approach was launched.

In addition, the administration of Remdesivir treatment under the Monitored Emergency Use of Unregistered and Experimental Interventions protocol was initiated.

As of today, various Sudan vaccine candidates are being tested in clinical research,

Previously, Zaire Ebolavirus vaccines and therapeutics had been approved for use in Africa,

In addition to Eboa, Uganda is experiencing polio and mpox outbreaks in 2026. Vaccines for these diseases are commercially available in the U.S.

Since Chikungunya was listed as a notifiable infectious disease by the Taiwan Centers for Disease Control (TCDC) in October 2007, a few travel-related and locally acquired cases have been reported most years.

As of April 25, 2025, the TCDC reports 11 Chikungunya cases this year, indicating a potential increase over last year's total of 20 cases.

And may approach 2019's record when 116 total cases were confirmed.

Previously, to identify infectious travelers, fever screening was conducted at the Taiwan Taoyuan International Airport.

The TCDC states that Chikungunya fever is rarely fatal; however, some patients may experience severe joint pain for several weeks, months, or even years. 

In the Asia Region, Chikungunya outbreaks have been recorded as early as 1824 in India.

As of April 25, 2025, the World Health Organization reports that Chikungunya transmission has occurred in approximately 110 countries, many of which are in the Americas, including Argentina and Brazil.

From a health perspective, this mosquito-transmitted disease can be prevented with U.S. Food and Drug Administration-approved vaccines, which are commercially available at travel clinics and pharmacies in the United States.

Merck today announced its financial results for the first quarter of 2025, which included a significant decrease in sales of its cancer prevention human papillomavirus (HPV) vaccines.

On April 24, 2025, Merck reported that GARDASIL/GARDASIL 9 vaccine sales declined 41% to $1.3 billion in 2025.

This decline is primarily due to lower demand in China, partially offset by higher demand in most international regions, particularly in Japan, as well as higher pricing and demand in the U.S.'

'Excluding China, sales grew 14%, or 16% excluding the impact of foreign exchange.'

Robert M. Davis, chairman and chief executive officer, Merck, commented in a press release, “We are working with focus and urgency to both realize the full potential of our near-term opportunities and to rapidly progress the next wave of innovation that will positively impact the lives of patients and drive future value creation for all of our stakeholders.”

The GARDASIL-9 vaccine remains the leading HPV vaccine in the United States, recommended by the U.S. CDC, and offered at most pharmacies.

Belize's Ministry of Health & Wellness recently announced the confirmation of locally transmitted malaria cases in Santa Elena Town and Cristo Rey Village, located in the Cayo District.

The initial case was detected on January 17, with additional instances detected on March 11 and April 5, 2025. Of the four confirmed cases in 2025, three are attributed to local transmission, and one is classified as imported from Guatemala.

Enhanced surveillance has been activated along the Western border, particularly in the Santa Elena neighborhoods of Santa Cruz and Hillview, as well as Cristo Rey Village.

As of April 23, 2025, these malaria cases mark the first instances of local transmission in over six years. However, other Central American countries have also reported outbreaks of malaria.

While this development is of concern, Belize remains committed to maintaining its malaria-free status, which was first achieved in June 2023.

The Ministry says malaria is a febrile disease caused by parasites, transmitted to humans through the bite of an infected Anopheles mosquito. Infected individuals typically experience episodes of fever with chills and sweating every 48 to 72 hours. 

The Ministry is actively testing individuals who currently have, or recently had, a fever within the past 30 days.

While malaria cases may continue in April, vaccines are not yet offered in the Region of the Americas.