Three out of every 4 U.S. children have been infected with COVID-19, Centers for Disease Control and Prevention researchers estimated in a new report, released on Tuesday.

Details: The researchers examined blood samples of more than 200,000 Americans for signs of antibodies made from infections.

  • They found a dramatic rise in these antibodies between December 2021 and February 2022, when the omicron variant had a surge.
  • Close to 60% of Americans over the age of 17 had signs of a prior infection.
  • Populations over 65 saw a lower increase. According to The Los Angeles Times, this may be due to higher vaccination rates and a more cautious attitude towards the virus.
  • These antibodies can be detected one to two years after initial infection.

What experts said: “I did expect it to increase. I did not expect it to increase quite this much,” Dr. Kristie Clarke, co-leader of a CDC team that tracks the extent of coronavirus infections, told The Associated Press.

Between the lines: The study does not dive into the role antibodies play in protecting individuals from future exposure.

“We still do not know how long infection-induced immunity will last, and we cannot know from the study, again, whether all people who tested positive for SARS-CoV-2 antibodies continue to have protection from their prior infection,” Clarke said.

The CDC advises those who have shown signs of previous infection to still get the COVID-19 vaccine. Unvaccinated people with a previous infection are five times more likely to get the coronavirus than those who are vaccinated, a CDC study showed.