Population Immunity and COVID-19 Vaccines

Can a COVID-19 Vaccine Create Population Immunity (Herd Immunity)?

We don't know yet. Studies show that the vaccines prevent severe COVID-19 disease, but we need more time to find out if they also prevent infection with or transmission of coronavirus.

How Population Immunity Works With Other Vaccines That Prevent Infection

• If no one is immunized, contagious disease spreads through the population.
• If some of the population gets immunized, contagious disease spreads through the unvaccinated population.
• If most of the population gets immunized, the virus has nowhere to go and can't spread to people who can't get immunized (babies, people who are immunocompromised) because they are protected by immunized people around them.

Why Is a COVID-19 Vaccine Different?

The studies have shown the COVID-19 vaccines are effective at preventing severe disease. This is important for the vaccinated people and their communities. It means people don't need so much time away from work or their families, and it means that the burden on hospitals and healthcare systems is reduced. We don't know yet if COVID-19 vaccines also prevent infection or prevent transmitting the virus to others. If people who are vaccinated can still get infected and transmit the virus to others, it will be harder to achieve population immunity.

We need the research to continue to help us find this answer.

Masks Are Still Needed to Stop The Spread of Coronavirus

Until we know if COVID-19 vaccines protect against infection, masks are still needed to stop the spread of coronavirus. Masks are the best way to stop the spread of droplets from your mouth and nose to others.