What are Inactivated Influenza Vaccines?
Inactivated influenza vaccines are a type of
influenza vaccine that contain virus particles which have been killed, or inactivated. These vaccines are designed to protect individuals from the influenza virus by stimulating the immune system to produce an immune response without causing the disease. Unlike live attenuated vaccines, inactivated influenza vaccines cannot cause influenza infection as they do not contain live virus.
How Do Inactivated Influenza Vaccines Work?
Inactivated influenza vaccines work by introducing inactivated virus particles into the body, which are recognized by the
immune system as foreign. This recognition triggers an immune response, including the production of
antibodies that can recognize and neutralize the live virus if the individual is exposed in the future. This process helps provide protection against influenza and reduces the severity of illness if infection occurs.
Who Should Receive Inactivated Influenza Vaccines?
The Centers for Disease Control and Prevention (CDC) recommends that everyone aged six months and older receive an annual influenza vaccine, with
inactivated influenza vaccines being a key option for most individuals. They are particularly recommended for those at high risk of
complications from influenza, including young children, the elderly, pregnant women, and individuals with certain chronic health conditions.
What Are the Benefits of Inactivated Influenza Vaccines?
Inactivated influenza vaccines offer several benefits. They are an essential tool in reducing the burden of influenza, including the number of cases,
hospitalizations, and deaths. Vaccination can also decrease the severity of illness and prevent the spread of the virus to others, contributing to community-wide protection known as
herd immunity. Additionally, these vaccines can be safely administered to people with weakened immune systems, who may not be able to receive live vaccines.
What Are the Side Effects of Inactivated Influenza Vaccines?
Inactivated influenza vaccines are generally safe and well-tolerated. The most common side effects are mild and temporary, including soreness at the injection site, low-grade fever, and muscle aches. Severe allergic reactions are rare but can occur, particularly in individuals with allergies to
vaccine components like egg protein. However, egg-free versions are available for those with severe egg allergies.
How Effective Are Inactivated Influenza Vaccines?
The effectiveness of inactivated influenza vaccines can vary from year to year, depending on how well the vaccine strains match the circulating virus strains. Generally, they reduce the risk of influenza illness by 40-60% when the vaccine strains are well-matched. Despite variations in effectiveness, vaccination remains the best method of protection against influenza and its complications.
How Are Inactivated Influenza Vaccines Developed?
Inactivated influenza vaccines are developed through a process that involves selecting virus strains predicted to be the most prevalent in the upcoming flu season. These strains are then grown in eggs or cell cultures, harvested, and inactivated. The vaccine is formulated to include components from multiple strains, typically covering two influenza A strains and one or two influenza B strains, providing broad protection. Can Inactivated Influenza Vaccines Be Administered with Other Vaccines?
Yes, inactivated influenza vaccines can be administered simultaneously with other
vaccines, using different injection sites. This is especially important during flu season, as it allows individuals to stay up to date with all recommended vaccinations without delay. Co-administration does not reduce the effectiveness of influenza vaccine or the other vaccines given.
What are the Future Directions for Inactivated Influenza Vaccines?
Research is ongoing to improve inactivated influenza vaccines, focusing on enhancing their effectiveness and broadening their protection. Efforts include developing universal influenza vaccines that provide long-lasting immunity against a wide range of influenza viruses. Advances in vaccine technology, such as
recombinant technology, are also being explored to produce vaccines that do not rely on egg-based production.
