List of seasonal influenza vaccines

Seasonal Influenza Vaccines are vaccines designed to protect against the influenza virus, which causes the flu, a contagious respiratory illness. These vaccines are updated annually to match the influenza viruses expected to be most prevalent during the upcoming flu season. The composition of the vaccine is determined by the World Health Organization (WHO) and national health agencies based on which influenza strains are circulating, how they are spreading, and how well the previous season's vaccine protects against current strains.

Types of Seasonal Influenza Vaccines

There are several types of seasonal influenza vaccines, each designed to induce immunity against the virus in different ways:

• Inactivated Influenza Vaccine (IIV): This vaccine contains killed virus and is given by injection. It is approved for use in people 6 months of age and older, including healthy people and those with chronic medical conditions.

• Live Attenuated Influenza Vaccine (LAIV): This vaccine contains a weakened form of the virus and is administered as a nasal spray. It is approved for use in individuals 2 through 49 years of age who do not have contraindicating health conditions.

• Recombinant Influenza Vaccine (RIV): This is a newer type of vaccine that does not use the influenza virus or eggs in its production. It is suitable for those aged 18 years and older, including those with egg allergies.

• High-Dose Influenza Vaccine: Specifically designed for people 65 years and older, this vaccine contains a higher dose of antigen to help create a stronger immune response.

• Adjuvanted Influenza Vaccine: This vaccine contains an additive that helps create a stronger immune response. It is also targeted at older adults.

Vaccine Composition

The seasonal influenza vaccine typically targets three or four influenza viruses that research indicates will be most common during the upcoming season. These include:

• Influenza A (H1N1) virus
• Influenza A (H3N2) virus
• One or two influenza B viruses

Effectiveness

The effectiveness of the seasonal influenza vaccine varies from year to year, depending on the match between the vaccine viruses and those circulating in the community. Vaccine effectiveness also varies among different age and risk groups.

Recommendations

Annual vaccination is recommended for all persons aged 6 months and older, with rare exceptions. Vaccination is particularly important for people at high risk of serious flu complications, including young children, pregnant women, people with chronic health conditions like asthma, diabetes, or heart and lung disease, and people 65 years and older.

Safety

Seasonal influenza vaccines have a good safety profile. Common side effects are mild and can include soreness, redness, or swelling at the injection site, low-grade fever, and aches.

Conclusion

Seasonal influenza vaccines are a key component of public health efforts to reduce the impact of the influenza virus. By vaccinating annually, individuals can protect themselves and others from the significant morbidity and mortality associated with the flu.