Article Translations: (Spanish)
A booster shot is a dose of vaccine given after a person has had the original vaccine (sometimes called a primary dose or, if more than one dose, primary series). Immunity from the original vaccine can fade over time, and a booster shot can help the immune system “boost” the protection it provides.
Booster shots are given for many vaccines that kids and adults get. These include:
Experts recommend that everyone age 6 months or older:
Even though these repeated flu and COVID-19 vaccines work by “boosting” the immune system response, experts don't call them booster shots. That's because they differ from the previous vaccines. They've been updated to fight the viruses as they change over time. They don’t just boost previous immunity — they provide new immunity. So health experts call them the annual flu vaccine and updated COVID-19 vaccine. But COVID-19 vaccines given after the primary series were called booster shots, so some people still call them that.
Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.
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