It takes about two weeks after getting the flu vaccine for the body to build up enough antibodies to provide protection against the flu. During these two weeks, the vaccine is not yet fully effective, so a person could still catch the flu if exposed. This is why it is recommended to get vaccinated before flu season begins, ideally by the end of October in the Northern Hemisphere, to ensure protection when flu activity increases.
Additional Details
- The flu vaccine stimulates the immune system to produce antibodies that protect against influenza viruses.
- Effectiveness varies depending on factors like age, health, and the match between the vaccine’s selected flu strains and circulating viruses.
- The protection from the vaccine can wane over time, so annual vaccination is recommended.
- Children and older adults may have specific vaccine formulations and timing recommendations.
In summary, one should expect about a 14-day period after vaccination before the flu shot is fully effective in guarding against influenza infection.
