CDC study shows three out of five in the US have had COVID-19

A study Tuesday by the Centers for Disease Control and Prevention shows that three out of five Americans have been infected with the virus that causes COVID-19, compared to one in three last fall, indicating how easily the omicron variant spread across the country during the winter. .

The study also found that children are more likely to become infected than older adults, with the rate among children rising from less than one in two last fall to three in four.

“These results show a high level of infection with the omicron variant, especially among children,” the CDC said in a statement.

But CDC officials warned that the results should not be interpreted to mean that people with signs of prior infection are protected from future reinfection, and continued to urge people to get vaccinated or boosted if possible.

“Vaccination remains the safest strategy to prevent complications from SARS-CoV-2 infection, including
hospitalizations among children,” the CDC said in a statement. “Vaccinating against COVID-19 after exposure provides additional protection against more severe illness and hospitalization. Therefore, timely vaccination
recommended for all eligible individuals, including individuals with prior SARS-CoV-2 infection.”

The study looked at the proportion of the U.S. population with “seroprevalence” or antibodies to SARS-CoV-2, the virus that causes COVID-19, to determine how many people have had the disease, which might have been missed in testing because some infections are asymptomatic, not diagnosed or not registered.

He studied seroprevalence from September 2021 to February 2022 with the National Age Group Survey, which estimates the proportion of infected populations in the 50 US states, the District of Columbia and Puerto Rico. In general, during the study period, it increased from 33.5% to 57.7%.

But the increase was greater among youth, from 44.2% to 75.2% among children aged 0-11 and from 45.6% to 74.2% among adolescents and adolescents 12-17 years old.

On the contrary, it increased from 36.5% to 63.7% among those aged 18–49, from 28.8% to 49.8% among those aged 50–64, and from 19.1% to 33. 2% among those aged 65 and over.

Vaccination rates are higher among the elderly, which may explain the lower number of previously infected among them, but the study also noted that they may be more careful than younger people about protecting themselves by avoiding crowds and wearing masks.

Dr. Christie E.N. Clarke, lead author, said a seroprevalence study could detect antibodies to the virus one to two years ago, so some of the total people had antibodies from earlier variants of the virus, although the recent increase over the winter reflects the omicron variant, which today accounts for all cases.

Clarke also said the study could not determine antibody levels that could indicate how protected a person would be from infection in the future.

“Having antibodies does not necessarily mean you are protected from infection,” Clarke said at the briefing. “Vaccination provides additional protection.”

The study is being conducted as the number of COVID-19 cases has increased, especially in the northeast, although they remain well below last winter’s levels due to newer omicron BA.2 and BA.2.12.1 sub-options. CDC director Dr. Rochelle Wallensky said on Tuesday that the number of cases in the country has increased by almost 23% and hospitalizations have increased by almost 7% over the past week, although the death rate has decreased by 13%.

But she said it remains unclear how much antibodies from a previous infection and vaccination will prevent a new surge in cases and hospitalizations.

“There are some areas of the country, especially in the northeast, where we are seeing higher cases and starting to see an increase in hospitalizations,” Wallensky said. “We are watching them closely.

Wallensky said there are no signs yet of an increase in intensive care admissions, suggesting more serious illnesses due to the rising number of cases.

“We hope the positive trends continue and we don’t see a further increase in disease severity,” Wallensky said. “That’s something we need to keep a close eye on.”