Most Americans have been infected with the coronavirus at least once, the CDC says.

“As a pediatrician and parent, I would absolutely endorse that children be vaccinated, even if they are infected,” said Dr. Clarke.

The number of coronavirus cases is on the rise again in the United States, particularly in the Northeast, but so far hospitalizations have been minimal and deaths are still declining.

Even among those hospitalized, “we’re seeing less oxygen use, fewer ICU stays. and thankfully we haven’t seen an increase in the number of deaths associated with it,” said CDC director Dr. Rochelle Walensky. “We are hopeful that the positive trends will continue.”

CDC researchers began assessing antibody levels in humans at 10 sites early in the pandemic and have since expanded that effort to all 50 states, the District of Columbia and Puerto Rico. The researchers use a test sensitive enough to identify previously infected people for at least a year or two after exposure.

The researchers analyzed blood samples collected from September 2021 to February 2022, looking for antibodies to the virus; they then analyzed the data by age, gender, and geographic location. The researchers specifically looked for a type of antibody that is produced after infection, but not in people who have only been vaccinated.

Between September 2021 and December 2021, the prevalence of antibodies in the samples steadily increased by one to two percentage points every four weeks. But it rose sharply after December and rose nearly 25 points in February 2022.

The percentage of samples with antibodies rose to about 75 percent from about 45 percent in both children 11 years and younger and adolescents 12 to 17 years.

By February 2022, about 64 percent of adults ages 18 to 49, about half of those aged 50 to 64, and about a third of older adults had been exposed to the virus, according to the study.

This post Most Americans have been infected with the coronavirus at least once, the CDC says.

was original published at “https://www.nytimes.com/2022/04/26/health/cdc-covid-infections.html”