Influenza Vaccine 2025: Protection and Prevention

     Ramkhamhaeng Hospital is committed to safeguarding lives and ensuring that everyone can navigate through disease outbreaks with minimal risk. To enhance protection and mitigate the severity of influenza, we have prepared the 2025 seasonal influenza vaccine, offering more effective prevention.

Understanding Influenza

     Influenza is a contagious respiratory illness caused by the Influenza Virus, with types A and B being the most common in humans. These viruses mutate rapidly and spread easily. Influenza A and B are further classified based on surface glycoproteins, designated by the letters "H" and "N," followed by specific numbers to indicate their subtypes.

The Importance of Subtype Identification

     For the immune system to effectively combat influenza, it must recognize and build immunity against the specific virus strain. For example, if an individual is exposed to the Influenza A (H1N1) virus, having immunity against H1N1 helps in preventing and reducing the severity of the illness. However, since influenza viruses mutate quickly into different subtypes, timely vaccination is crucial.

Suitable Time for Vaccination

     Influenza outbreaks are not limited to the rainy and winter seasons (March–May and October–November) but can occur year-round. Therefore, receiving the vaccine before the peak seasons allows for better protection against severe outbreaks.

2025 Influenza Vaccine

     As influenza viruses evolve annually, the World Health Organization (WHO) recommends specific virus strains for surveillance and vaccination. For 2025, the recommended strains for the Southern Hemisphere (SH) are:

1.  Southern Hemisphere Influenza Vaccine (SH 2025)

• A/Victoria/4897/2022 (H1N1)pdm09-like virus
• A/Croatia/10136RV/2023 (H3N2)-like virus
• B/Austria/1359417/2021 (B/Victoria lineage)-like virus
• B/Phuket/3073/2013 (B/Yamagata lineage)-like virus

2.  Northern Hemisphere Influenza Vaccine

• A/Victoria/4897/2022 (H1N1)pdm09-like virus
• A/Thailand/8/2022 (H3N2)-like virus
• B/Austria/1359417/2021 (B/Victoria lineage)-like virus
• B/Phuket/3073/2013 (B/Yamagata lineage)-like virus

Q&A: Common Questions About the 2025 Influenza Vaccine

1. Who should receive the influenza vaccine?

The vaccine is recommended for individuals aged six months and older, including those in high-risk groups:

• Individuals with obesity
• Pregnant women (from the fourth month of pregnancy)
• Young children under two years old and elderly individuals aged 65 and above
• Individuals with weakened immune systems
• Patients with chronic conditions such as asthma, diabetes, or hypertension

2. How long does immunity last?

     Immunity lasts for approximately one year after a single vaccine dose, reducing the risk of contracting influenza by 70–90%. It is recommended to receive the vaccine at least two weeks before international travel to allow the immune system to build protection.

3. Can I Receive The Influenza Vaccine During The COVID-19 Pandemic?

     Yes, receiving the influenza vaccine before contracting COVID-19 can reduce hospitalization duration and the severity of symptoms compared to individuals who have never been vaccinated against influenza prior to COVID-19 infection.

By staying informed and vaccinated, individuals can effectively protect themselves and those around them from influenza and its complications.