New research finds that mRNA COVID-19 vaccines provide viral immunity for at least 6 months, but since COVID-19 is so new, experts aren’t sure if immunity will wane after that. A vaccine is a medicine designed to defend against diseases by introducing the immune system to a virus in a safe way. This process allows the immune system to learn how to defeat it by generating antibodies specific to the virus. These antibodies will help ward off future infections and in some cases prevent re-infection. Scientists are still researching how long antibodies last for coronavirus (COVID-19), which could inform how long a vaccine will last.