Is Covid-19 Exposure Post-Vaccination a Booster or a Risk?

Will circulating variants of Covid-19 “boost” immunity in vaccinated populations?

As the first group of people to receive Covid-19 vaccines reach the 6 month mark, the natural question in many people’s minds is: how long will this vaccine protect us against the virus? While research shows lasting and powerful protection, there is still concern that that immunity will fade with time. This raises the question of whether boosters are needed to prop up immunity.

With variants of the SARS-CoV-2 virus still actively circulating amidst easing restrictions, many vaccinated individuals will likely be exposed to the virus. So the question is, will post-vaccination exposure to Covid-19 serve as a natural booster?

Vaccination boosters are not uncommon. Many of the vaccines that we receive as young children often need a booster later in life. This is necessary for some pathogens because (for reasons not fully understood) the vigorous immunity that comes shortly after vaccination fades over time. The degree of lasting protection — what researchers call durable immunity — is a critical metric in determining vaccine schedules. Unfortunately, durable immunity varies from one pathogen to the next.