“As a pediatrician and parent, I will definitely support children being vaccinated even if they have been infected,” said Dr. Clarke.
Coronavirus cases are rising again in the United States, especially in the Northeast, but so far the increase in hospitalizations has been minimal and deaths are still falling.
Even among those admitted, “we are seeing less oxygen consumption, fewer ICU stays, and fortunately we have not seen any increase in deaths associated with them,” said CDC Director, Dr. Rochelle Walensky. “We hope the positive trends will continue.”
CDC researchers began assessing antibody levels in humans at 10 locations early in the pandemic and have since extended that effort to all 50 states, the District of Columbia and Puerto Rico. Investigators use a test that is sensitive enough to identify previously infected people for at least a year or two after their exposure.
The researchers analyzed blood samples collected from September 2021 to February 2022 and looked for antibodies against the virus; then they analyzed the data by age, gender, and geographic location. Investigators specifically looked for a type of antibody produced after infection, but not in individuals who have simply been vaccinated.
Between September 2021 and December 2021, the prevalence of antibodies in the samples increased steadily by one to two percentage points every four weeks. But it rose sharply after December and rose by almost 25 points in February 2022.
The percentage of samples with antibodies increased to about 75 percent from about 45 percent among both children aged 11 years and younger and adolescents aged 12 to 17.
By February 2022, about 64 percent of adults 18 to 49, about half of those 50 to 64, and about one-third of older adults had been infected with the virus, according to the study.