If immunity to influenza wanes, why does a child need only one dose instead of two doses if they were vaccinated in a previous influenza season?
The first dose of influenza vaccine given to a child younger than 9 years of age is a “priming” dose. It offers little protection. It is the second dose that offers the protection. There is no need for priming in subsequent years, so only one dose is recommended. Persons 9 years of age and older are assumed to have been exposed to influenza viruses, and will have been primed by that exposure. Therefore, they do not need a second dose of vaccine in one year, even if they are receiving it for the first time. Booster doses are not recommended for anyone because data do not indicate that booster doses increase protection.
Related Questions
- If immunity to influenza wanes, why does a child need only one dose instead of two doses if they were vaccinated in a previous influenza season?
- What if during that given time frame, my child received more than one dose of the same vaccine - how many doses will need to be repeated?
- If a child received 4 or more doses of IPV before their 4th birthday, is another dose necessary?
