The best time to get a flu shot is generally in September or October, before flu season starts to ramp up. This timing balances getting protected before flu viruses circulate widely, which typically peaks between December and February, and ensuring the vaccine protection lasts through the season. Special groups have specific timing recommendations:
- Pregnant women in their third trimester might get vaccinated earlier (as early as July or August) to protect the newborn.
- Children requiring two doses should start early, as soon as the vaccine is available, often from September.
- Adults 65 and older are advised to get vaccinated in September or October with high-dose or adjuvanted vaccines due to faster waning immunity.
- For most adults, vaccination appointments usually start from October.
If the flu shot is missed in this recommended window, it is still beneficial to get vaccinated later in the season while flu viruses are circulating, which can be as late as May. Protection begins about two weeks after vaccination, so getting the shot before the end of October is ideal for best coverage during peak flu months. In summary, aim for vaccination in early fall (September or October) for optimal protection, with some exceptions depending on age, pregnancy, and vaccination history of children.
