Zika Breaking News

The Lancet Infectious Diseases recently published results from a phase 2 clinical trial of the Lyme disease vaccine candidate, VLA15.

The Valneva SE and Pfizer Inc.-funded study showed a strong immune response following a third booster dose, with a favorable safety profile.

These researchers wrote on November 7, 2025, that the results are consistent with those observed following previous annual booster doses, further supporting the expected benefits of a yearly vaccination before each Lyme season.

They concluded, 'The safety and robust anamnestic immune responses associated with VLA15 boosting support its use as a strategy to increase anti-OspA antibody levels before tick season among children, adolescents, and adults.'

This study's findings are essential to public health as the the Centers for Disease Control and Prevention estimates that approximately 476,000 people in the U.S. are diagnosed and treated for Lyme disease each year, and 132,000 cases are reported annually in Europe.

As of November 14, 2025, VLA15 is the most advanced Lyme disease vaccine candidate.

Since the Zika virus disease was first detected in the Americas in May 2015, over 50 countries and territories in the region have reported cases transmitted by mosquitoes.

Unfortunately, the Federative Republic of Brazil has historically led in the number of cases.

As of November 13, 2025, the Pan American Health Organization (PAHO) reported Brazil has confirmed 22,831 cases of Zika this year alone. Many of these cases are found in the city of Rio de Janeiro, which is home to over 6 million people.

The other countries with the highest case numbers in 2025 include Bolivia, with 1,024 cases, and Argentina, with 892 cases.

Additionally, near the southern border of the United States, Mexico has reported three cases of Zika in 2025, down from 30 cases reported last year.

The PAHO writes, 'While efforts are underway to improve the sensitivity of surveillance systems, a lack of detection is no guarantee that the Zika virus is not circulating or that local transmission has been interrupted.'

Currently, the U.S. CDC reports no geographic areas with an active Zika Travel Health Notice.

The PAHO and the CDC discourage pregnant women from visiting Zika-endemic areas.

From a disease-prevention perspective, one innovative Zika vaccine (VLA1601) is progressing through clinical trials in 2025.

Malaria infections in sub-Saharan Africa are increasingly showing resistance to artemisinin-based therapies, posing a significant threat to the effectiveness of antimalarials against the mosquito-transmitted parasite.

However, a novel non-artemisinin antimalarial from Novartis has demonstrated that it is as effective as standard treatment.

On November 12, 2025, Novartis announced positive results from KALUMA, a Phase III study for the new malaria treatment KLU156 (ganaplacide/lumefantrine, or GanLum).

This drug was developed with Medicines for Malaria Venture and met the study's primary non-inferiority endpoint relative to the current standard of care. The treatment achieved a 97.4% PCR-corrected cure rate using an estimand framework, compared to 94% with standard of care.

This data equates to cure rates of 99.2% and 96.7% respectively, based on conventional per-protocol analysis.

"GanLum could represent the biggest advance in malaria treatment for decades, with high efficacy against multiple forms of the parasite as well as the ability to kill mutant strains that are showing signs of resistance to current medicines," said Dr Abdoulaye Djimdé, Professor of Parasitology and Mycology at the University of Science, Techniques and Technologies of Bamako, Mali, in a press release.

"Drug resistance is a growing threat to Africa, so new treatment options can't come a moment too soon."

GanLum is a combination of two compounds that attack the malaria parasite on multiple fronts: ganaplacide, a novel compound with an entirely new mechanism of action, and a new once-daily formulation of the existing antimalarial lumefantrine, a longer-acting treatment. 

Ganaplacide is believed to work by disrupting the parasite's internal protein transport systems, which are essential to its survival within red blood cells.3 It belongs to a class of compounds called imidazolopiperazines, first identified as potential antimalarials after a groundbreaking screen of 2.3 million molecules to find drug candidates at Novartis labs in San Diego, California.

Novartis plans to seek regulatory approvals from health authorities for GanLum as soon as possible. 

If approved, the drug could be used to treat international travelers returning to the United States after being infected.

For example, in Florida, 43 travel-related malaria cases have been confirmed in 2025, 15 related to travel to Nigeria. 

From a malaria prevention option, about 24 countries are now offering malaria vaccinations, but not the USA.

Infection with the mpox virus (MPXV) confers stronger immunity against future infection than vaccine-conferred protection, which wanes over time and requires boosting, researchers wrote in The Lancet Infectious Diseases on November 7, 2025.

These findings suggest that MPXV infection confers long-term protection against reinfection, whereas vaccine-induced immunity can wane over time and requires boosting.

These researchers wrote that further studies are needed to determine whether booster doses can enhance the durability of immunological memory in previously vaccinated individuals.

Should booster vaccination prove beneficial, targeted revaccination campaigns will be necessary to maintain population-level protection.

In a related commentary, researchers from the Icahn School of Medicine at Mount Sinai said that the study's findings indicate that the success of next-generation vaccines against orthopoxviruses, such as mpox, will depend on antigen selection that focuses immune responses on proteins associated with long-lasting protection and cross-reactivity against multiple orthopoxviruses.

Currently, the U.S. FDA-approved JYNNEOS (MVA-BN) mpox/smallpox vaccine is offered at clinics and pharmacies in the United States.

Funding for this study was from the Research Foundation–Flanders, Department of Economy, Science and Innovation Flanders, and the Netherlands Organization for Health Research and Development.

Japanese encephalitis virus (JEV) is the leading cause of epidemic encephalitis worldwide and is prevalent across Asia and the Pacific.

A recent study published in the journal Nature highlights significant public health concerns stemming from changes in the dominant genotype, the emergence of epidemics in new regions, and the re-emergence of previously dormant genotypes.

The re-emergence of specific genotypes in Indonesia after 37 years, coupled with JEV-related fatalities in Australia, Nepal, and Taiwan, highlights the need for critical control measures.

Nepal's Department of Health Services has confirmed 164 cases of Japanese encephalitis in 2025, compared to 86 last year.

In 2024, 23 people died in Nepal infected with the JEV.

Similarly, the resurgence of genotype in China after 57 years and its circulation in Korea underscore the need for continuous surveillance and proactive vaccinations.

According to the U.S. CDC, a Japanese encephalitis vaccine (IXIARO) is available in the United States, approved for use in children aged 2 months and older and adults.

The CDC says this approved vaccine should be considered for some travelers before visiting high-risk areas in 2025.

In the United States, IXIARO is commercailly offered at travel clinics and pharmacies.

Currently, no vaccines or therapeutics are licensed against Lassa fever, an acute viral hemorrhagic illness caused by Lassa virus (LASV) that is responsible for thousands of deaths each year across West Africa, where the disease is endemic. 

The findings from a first-in-human, Phase 1 clinical trial of IAVI's LASV vaccine candidate, published in the New England Journal of Medicine on November 6, 2025, demonstrate that one dose of the vaccine elicits robust and long-lasting immune responses and has an acceptable safety profile.

"Lassa fever is a cruel disease which has plagued West Africa for decades, including a deadly outbreak in Nigeria this year," said Dr. Kent Kester, Executive Director of Vaccine R&D at CEPI, in a press release.

"The promising Phase 1 data for IAVI's vaccine candidate takes us one step closer towards a much-needed Lassa fever vaccine, which, if successful, could save thousands of lives and avert millions of dollars of societal costs in the West African countries that bear the burden of this disease."

The Israeli Ministry of Health recently reported the ninth measles-related fatality in a child since an outbreak began earlier in 2025.

On November 9, 2025, a child from Jerusalem with an underlying health condition, who had received one dose of the measles vaccine, passed away at an emergency department due to complications from the disease.

As of today, 16 patients are hospitalized after contracting measles.

Until now, all previous measles cases involved healthy infants with no underlying conditions who were unvaccinated.

The Ministry of Health reiterated in a press release that measles is preventable with a safe and effective vaccine. It emphasizes the importance of seeking medical care promptly if symptoms appear or if exposure to measles is suspected.

Since May 2025, the U.S. CDC has included Israel in its Global Measles travel advisory.

The CDC says all international travelers should be fully vaccinated against measles before departing abroad. Measles vaccination services are offered at travel clinics and pharmacies in 2025.