Nearly 60% in U.S. Likely Had Covid-19

"Nearly 60% of people in the U.S., including three in four children, exhibited signs of previous Covid-19 infection as of February, a Centers for Disease Control and Prevention report said.

The estimated proportion of people in the U.S. with detectable, infection-induced antibodies jumped from 34% in December 2021 to 58% by February 2022, according to a study the CDC released Tuesday, highlighting the reach of the winter Omicron surge that washed over the country.

"We do believe that there is a lot of protection in the community both from vaccination, as well as from boosting and from prior infection," CDC Director Rochelle Walensky said. "Those who have detectable antibodies from prior infection, we still continue to encourage them to get vaccinated."

At the height of the winter Omicron wave, the seven-day average for known cases topped 800,000 a day, by far the highest level ever recorded. The rise in at-home testing and lack of testing access for many people, among other factors, likely meant that many more cases went uncounted.

In part because of the sheer number of infections, the Omicron surge in the U.S. was also one of the deadliest; the seven-day moving average went above 2,500 deaths a day in early February, Johns Hopkins University data show.

To get a better sense of the true breadth of infection, federal researchers have attempted to estimate and track the seroprevalence, or the proportion of people in the population with detectable antibodies.

Looking at blood-sample data from the national commercial laboratory seroprevalence survey, which estimates the U.S. seroprevalence from infection, the CDC found that the proportion of antibodies from prior infection increased substantially across every age group from December to February.

People age 65 and above saw the proportion of antibodies increase from 19% to 33%, compared with those 50 to 65 increasing from 29% to 50%, and those 18 to 49 having a prevalence increase from 37% to 64%, the study found.

The increases might be underestimates, because data suggest that infections following vaccination might be less likely to result in detectable infection-induced antibodies, said Kristie Clarke, co-lead for the Covid-19 Epidemiology and Surveillance Taskforce Seroprevalence team at the CDC and lead author of the study.

Infection-induced antibodies increased most sharply for children and adolescents, the least-vaccinated age group, with an estimated 75% of them having detectable antibodies by February. Approximately one-third of them became newly seropositive since December, the study found." [1]

 

If this coronavirus, which attacks the nervous system, will, over time, cause the development of Alzheimer's disease in most surviving the infection people, then such a high number of infected will become the most important fact in the history of epidemiology.

 

1.  U.S. News: Nearly 60% in U.S. Likely Had Covid-19
Abbott, Brianna.
Wall Street Journal, Eastern edition; New York, N.Y. [New York, N.Y]. 27 Apr 2022: A.3.