Estimates of the number of COVID-19 infections during the pandemic have almost doubled to 140 million cases, or 43 percent of Americans, based on a new nationwide antibody seroprevalence survey by the Centers for Disease Control and Prevention.
The CDC collaborated with state, local, academic and commercial sources to test blood samples for COVID-19 antibodies generated by infection rather than vaccination. The survey then used the seroprevalence measurements to estimate the percentage of the population with a previous infection. Researchers hoped this method would better account for people who were not tested, either because they had no symptoms or were not tested.
As of Jan. 31, 74.3 million cases had been reported nationally, according to the CDC.
The same survey found 38.9 percent of Connecticut residents have been infected, with 1,393,000 estimated cases after the CDC reported 696,712 cases through Jan. 31. And 46.8 percent of the state’s children, up to 17 years old, likely have been infected.
These new numbers, unfortunately, do not build a case for herd immunity, which requires a high percentage of the population with immunity through infection or vaccination.
“We’ve never really believed in the concept of herd immunity for this disease,” says Dr. Ulysses Wu, Hartford HealthCare’s System Director of Infection Disease and Chief Epidemiologist. “Herd immunity does exist for other things: We always cite chickenpox parties (where children were deliberately exposed to the infectious disease) because, for chickenpox, it is long-lasting immunity.
“Before COVID-19, you would always have your common cold. That common cold was usually due to a number of respiratory viruses, some of which included coronaviruses. If there was long-lasting immunity to the common cold, we wouldn’t get that common cold every year.”
Here’s the age breakdown of infections nationally by age:
Percent of United States Population (By Age) Infected During COVID-19 Pandemic
- 0-17 years old: 57.8 percent.
- 18-49 years old: 48 percent.
- 50-64 years old: 37.1 percent.
- 65 years old and up: 23.3 percent.
Connecticut’s new infection estimate ranks 35th among the 46 states with available data, according to the CDC.
Here’s the breakdown of infections in the state by age:
Percent of Connecticut Population (By Age) Infected During COVID-19 Pandemic
- 0-17 years old: 46.8 percent.
- 18-49 years old: 43 percent.
- 50-64 years old: 35.3 percent.
- 65 years old and up: 23.3 percent.
Wisconsin, at 56.1 percent of its population infected during the pandemic, had the nation’s highest seroprevalence. Vermont, at 17.8 percent, had the lowest.