1) Immunity from COVID vaccines wanes over time Some vaccines, such as the MMR vaccine (measles, mumps and rubella), can provide lifelong protection.
In contrast, the effectiveness of COVID vaccines begins to decline in the months afterwards. Immunity doesn’t simply drop off a cliff.
It’s a more gradual decline, with a typical reduction of about 21% in protection against infection and 10% against severe disease in the six months after vaccination.
Although the decline in immunity can be more pronounced in the elderly and those with weakened immune systems, all age groups are affected.