Ask the Experts: What Is Herd Immunity?

Q. Throughout the pandemic, I’ve heard the term herd immunity bounced around. What exactly is that? Herd immunity occurs when enough individuals in a community have acquired immunity against a particular infection to make person-to-person transmission less likely. An individual’s immunity can be acquired by either getting vaccinated against the infection or contracting the infection. […]

Related Articles

  • August 1, 2019

    Amid the 2019 resurgence of measles in the U.S., several readers in their 50s and 60s asked us if they should get vaccinated, especially if they couldn’t remember having had measles or getting the vaccine previously. While the uptick in cases of measles have significantly decreased since then, our advice remains the same. If you […]

  • June 1, 2020

    People who get information about vaccines from social media are more likely to be misinformed than those who learn about vaccines from traditional news outlets, suggested the findings of a survey of nearly 2,500 Americans in 2019, when the nation experienced a large measles outbreak.* The respondents were interviewed two times, separated by five months, […]