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Q: How do people who have not been vaccinated against COVID-19 pose a risk to people who have been vaccinated?

A: An unvaccinated person who is infected with COVID-19 poses a much greater risk to others who are also unvaccinated. But vaccines are not 100% effective, so there is a chance that an unvaccinated person could infect a vaccinated person — particularly the vulnerable, such as elderly and immunocompromised individuals.

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