Dec. 7, 2021

With the Omicron variant of Covid-19 spreading across the country, the need for a booster shot or an additional jab may feel more urgent than ever.

What is an additional dose of a Covid-19 vaccine?

  • An additional dose, originally called a third dose, is given to people with moderately or severely compromised immune systems to improve their response to the initial vaccine series.

  • The term “third dose” was used to refer to additional doses for the two mRNA vaccines, but now the term is “additional dose” because those who received a Johnson & Johnson “one dose” vaccine may also be eligible for a dose based on their immune systems.

  • People with weakened immune systems might not develop enough immunity after vaccination with two doses of a vaccine. An additional dose, thus, might improve their protection against the novel coronavirus.

What is a booster shot?

  • A booster shot is nothing but a means of strengthening one’s immune system against a particular pathogen. It may be exactly the same original vaccine, in which case its goal is to increase the magnitude of protection by producing more antibodies.

  • The booster shot is an additional dose after the protection provided by the original shot(s) has started to decrease over time.