NEW YORK (AP) — Three out of four American children have been infected with the coronavirus, researchers at the Centers for Disease Control and Prevention estimated in a report on Tuesday.
The researchers analyzed blood samples from more than 200,000 Americans and looked for antibodies that fought the virus from past infections, not from vaccines. They found that signs of past infections rose sharply between December and February, when the more contagious Omicron variant emerged in the United States.
The most notable surge occurred among children. The share of people under 17 with antibodies climbed from about 45% in December to about 75% in February.
For Americans of all ages, around 34% had signs of prior infection in December. Just two months later, that figure stood at 58%.
“I expected it would rise. I didn’t expect it to rise so much,” said Dr. Kristie Clarke, co-leader of a CDC team tracking the reach of coronavirus infections.
The older the age group, the less likely it was to show evidence of past infection, the study found. Among those older than 65, 19% had signs of prior infection in December and 33% in February. That may reflect higher vaccination rates among older adults and their greater likelihood of taking other precautions against COVID-19, such as wearing masks and avoiding crowds, Clarke said.
Clarke noted that the tests can detect antibodies for one to two years after infection, and possibly longer.
Studies have shown that a past infection can protect some people against severe illness and hospitalization, but CDC officials emphasized that people who were previously infected should still get vaccinated against COVID-19.
The study looked for any detectable level of antibodies; it did not distinguish how many people had antibody levels that might be protective. Scientists are still
