Vaccine News

The World Health Organization (WHO) recently published a technical brief on encephalitis, a serious, life-threatening neurological condition characterized by brain inflammation.

On February 17, 2025, the WHO stated that different pathogens, such as herpes simplex virus (HSV), can cause encephalitis. 

Some pathogens, like the Japanese encephalitis virus (JEV), are spread by mosquitoes and ticks, but vaccination can prevent transmission.

As of 2025, JEV outbreaks are the leading cause of viral encephalitis in twenty-four countries in the WHO South-East Asia and Western Pacific Regions, exposing more than 3 billion people to infection risks.

For example, the WHO reported various JEV cases across Australia, including Queensland, New South Wales, South Australia, Victoria, the Australian Capital Territory, Tasmania, Western Australia, and the Northern Territory.

Encephalitis affects people across all age groups, has high mortality, and often leads to significant long-term complications (sequelae), including hearing loss, seizures, limb weakness, and difficulties with vision, speech, language, memory, and communication.

Globally, in 2021, encephalitis was the fourth leading cause of neurological health loss in children aged under 5 years and the 13th across all age groups.

"Encephalitis is a growing public health challenge, and by prioritizing it within global and national health agendas and strengthening collaboration, we can reduce its impact and save lives," said Dr Tarun Dua, Head of the Brain Health Unit, WHO, in a press statement.

The WHO technical brief, which forms part of the implementation of the broader Intersectoral global action plan on epilepsy and other neurological disorders, draws attention to the lack of access to essential care, especially in low-and middle-income countries. 

While no HSV vaccines are authorized, the U.S. FDA-approved JEV vaccine, IXIARO®, is available at clinics and pharmacies nationwide. According to the U.S. CDC, vaccination is recommended before visiting JEV outbreaks.

Health ministries worldwide recently met at the WHO Executive Board meeting in Geneva. They expressed serious concern about the increasing transmission of wild poliovirus in Asia's last two endemic countries: Pakistan and Afghanistan.

The total number of polio cases in Afghanistan for 2024 was 25, and Pakistan reported 74 cases in 2024.

These ministers noted that 'extraordinary measures were being taken in response.'

WHO Member States commended the implementation of new emergency operational approaches in both countries. 

These approaches include identifying the different operational reasons why children are not being reached, area by area; increasing co-administration of inactivated polio vaccine (IPV) alongside oral polio vaccine (OPV); boosting overall immunity levels in children; and improving access to more adequate sanitation infrastructures.

Member States expressed concern about the ongoing variant poliovirus outbreaks (circulating vaccine-derived polioviruses) and urged intensified response to stop these outbreaks by maximizing the impact of novel oral polio vaccine type 2 (nOPV2).

This triple-locked polio vaccine has been administered over 1 billion times recently.

Speaking on behalf of the Eastern Mediterranean Region, Regional Director Dr Hanan Balkhy commented in a media statement, “I assure you, on behalf of our Region and the leaders of both endemic countries, our commitment to eradicating this virus is stronger than ever. We must reach and vaccinate every child and keep up a robust search for poliovirus, to stop further spread."

In Europe, the unusually high number of poliovirus detections has reinforced the urgency of the wake-up call. From September through December 2024, vaccine-derived poliovirus type 2 was detected in wastewater systems of 14 cities in five European countries.

As of February 21, 2025, IPV vaccination is recommended for most people in the United States. Furthermore, a booster dose may be advised for international travelers visiting polio outbreak areas.

Throughout the record-setting Dengue fever outbreak in the Region of the Americas in 2024, most international travelers were unprotected when visiting at-risk countries such as Brazil, Costa Rica, and even Miami Breach.

Furthermore, once infected with this mosquito-transmitted viral disease, patients could not access innovative therapies.

To accelerate the approval of Dengue treatments, the U.S. National Institutes of Health (NIH) is testing an experimental treatment.

The phase 2 clinical study will involve exposing volunteers to a weakened strain of dengue virus that causes a mild form of the disease and administering an investigational therapeutic at various doses to assess its safety and ability to lessen symptoms.

This NIH clinical trial will test the ability of AV-1, an investigational human monoclonal antibody (mAb) therapeutic developed by AbViro, to mitigate clinical symptoms when administered before and after dengue virus infection at Johns Hopkins Bloomberg School of Public Health Center for Immunization Research and the University of Vermont.

However, none of the volunteers will develop dengue fever or severe dengue during this study.

“When caring for a patient who is critically ill with dengue, healthcare providers have few options other than providing supportive care,” said NIAID Director Jeanne Marrazzo, M.D., M.P.H., in a press release on February 11, 2025.

“We must find safe and effective therapeutics to provide much-needed relief to people suffering from dengue.”

The researchers will use this information to determine how AV-1 affects the volunteers’ ability to recover from dengue compared to placebo and to determine the dosages at which AV-1 may be effective.

If AV-1 shows promising results in this clinical trial, researchers may pursue further clinical evaluations of its safety and efficacy against the dengue virus.

The results of a previously completed Phase 1 trial indicated that AV-1 is safe in humans, providing the basis for the new clinical trial to test its safety and efficacy.

Another Dengue mAb candidate, Dengushield (VIS513), is being evaluated in phase 2 clinical trials.

This mAb is a highly potent inhibitor of all four types of dengue viruses, both in vitro and in preclinical animal models. Dengushield was licensed to the Serum Institute of India Pvt. Ltd. for development.

Despite these potential innovations, during Spring Break 2025, preventing mosquito bites is the best tactic to avoid Dengue infection.

The U.S. CDC's Advisory Committee on Immunization Practices (ACIP) today announced it has postponed next week's vaccine review meeting. This ACIP meeting was scheduled from February 26 to 28, 2025.

The draft agenda had been posted in early February. 

As of February 20, 2025, the CDC's website stated, 'The ACIP workgroups met as scheduled this month and will present at the upcoming ACIP meeting.'

The next regularly scheduled ACIP meeting is in late June 2025.

The ACIP holds about three annual meetings, which are open to the public. At these meetings, scientists review scientific data and vote on vaccine recommendations. The ACIP recommendations are then passed on to the CDC's Director, who makes the final decisions.

With the detections of the Eurasian H5 strain of highly pathogenic avian influenza (HPAI) in wild birds, domestic poultry, and mammals over the past few years, Canada took action today to prepare for a pandemic.

As of February 19, 2025, the Public Health Agency of Canada (PHAC) and its partners have secured an initial supply of 500,000 doses of GSK's human vaccine against HAPI infections – Arepanrix H5N1 A/American wigeon clade 2.3.4.4b.

This U.S. FDA-approved vaccine will be part of Canada's contingency planning. PHAC will provide vaccines to provinces and territories using an equitable and risk-based approach. Sixty percent of available doses will go to provinces and territories, and 40 percent will be kept in a federal stockpile.

It is common to detect avian influenza in wild birds, as viruses circulate freely in those populations without the birds appearing sick. While the current risk to the public remains low, individuals with higher-level exposure to infected animals are at increased risk for avian influenza.

Dr. Theresa Tam, Canada's Chief Public Health Officer, commented in a press release, "By making human vaccines against avian influenza  available for potential use in individuals at increased risk of exposure to avian influenza as part of our readiness, we are enhancing our capacity to protect people in Canada and respond  rapidly to emerging public health challenges."

The health agencies of the United States, the United Kingdom, Japan, Europe, and China have already approved and purchased avian influenza vaccines.

The Texas Department of State Health Services today is reporting an expansion of the measles outbreak in Texas.

As of February 18, 2025, the South Plains region has confirmed that 58 cases have been identified with symptom onset within the last three weeks. Fifty-four of these measles patients are unvaccinated or have unknown vaccination status.

Due to the highly contagious nature of this disease, additional outbreaks are likely to occur in Gaines County, Lubbock, Lynn, Terry, and Yoakum countries in western Texas.

DSHS released a media release stating it 'is working with South Plains Public Health District and Lubbock Public Health to investigate the outbreak.'

Just a few miles west of this Texas outbreak, the New Mexico Department of Health reported three residents tested positive for measles in February 2025.

Earlier in 2025, two measles cases were reported in the greater Houston area.

In 2024, the leading measles outbreaks in the U.S. were reported in Minnesota (70) and Illinois (67).

From a prevention perspective, the MMR vaccine has been found to be very effective against measles outbreaks. This vaccine is generally available at clinics and pharmacies throughout the United States.

CSL and Arcturus Therapeutics recently announced that the European Commission (EC) has granted marketing authorization for KOSTAIVE ®, a self-amplifying mRNA COVID-19 vaccine, for individuals 18 and older.

KOSTAIVE (ARCT-154)is the first sa-mRNA COVID-19 vaccine to receive approval from the EC.

"KOSTAIVE and sa-mRNA technology signify a major advancement in vaccine innovation, providing the potential for broader and more enduring protection," said Joseph Payne, CEO of Arcturus, in a press release on February 14, 2025.

"This approval highlights the clinical promise of KOSTAIVE and its ability to protect against the ever-changing COVID-19 virus."

Unlike standard mRNA vaccines, self-amplifying mRNA vaccines instruct the body to make more mRNA and protein to boost the immune response.

KOSTAIVE is currently marketed in Japan against COVID-19.