This also helps protect people who can’t get vaccinated for health reasons, and people who work in crowded or indoor places. Many scientists think at least 70 percent of people need to have acquired immunity for the whole community to be protected. It’s likely that some regions will have higher vaccination rates than others. Just as some communities have found themselves vulnerable to measles because of low childhood vaccination rates, areas with low Covid-19 vaccination rates may see outbreaks even if the country has reached a herd immunity level over all. Vaccines can expand an individual’s risk budget, Professor Lofgren said.

Source: New York Times December 21, 2020 10:01 UTC