Seasonal Flu Vaccine Awareness 2021 · FDA.gov: #FluVaccineByHalloween · NJ Dept. of Health · CDC.gov · For College Students · Vaccine Finder
Ideally, everyone should be vaccinated by the end of October. September and October are generally best times to be vaccinated, as it takes four to eight weeks for flu antibodies to grow to full strength within your immune system.
Influenza vaccines given with a needle (a flu shot) do contain an inactivated (killed) virus or are made with a single protein from the virus to stimulate an immune response, but they cannot give you the flu. The nasal spray vaccine works a bit different as it contains live viruses, but they are weakened and only multiply within the nose due to temperature. This method also protects against the flu but cannot give you the flu.
The flu season can last as late as May. Getting the vaccine later in the season can still protect you.
Adults, especially those older than 65, should not get vaccinated before September because protection in this group may decrease faster.
Children can get vaccinated as soon as vaccine becomes available. Some children need two doses. For those children it is recommended to get the first dose as soon as vaccine is available, because the second needs to be given at least 4 weeks after the first.
Early vaccination should be considered for those in the third trimester of pregnancy, because this can help protect infants during the first months of life when they are too young to be vaccinated.
Children who are 6 through 59 months of age and attending licensed child care and preschool facilities in New Jersey are required to have flu vaccine by December 31 of each year.