New data from the Centers for Disease Control and Prevention shows as many as 45 percent of Connecticut residents — more than 1.5 million people — may have contracted COVID-19, far more than the number of confirmed cases reported by the state.
Among younger people, the proportion is far higher. CDC data shows as many as two out of every three residents under the age of 18 may have contracted COVID-19.
According to state data released Wednesday, there have been a total of 817,999 COVID cases reported in Connecticut. But the CDC says there may have been 1.59 million total infections in the state.
The CDC conducts random testing for COVID antibodies, called seroprevalence studies. If those antibodies are found in a person’s blood, they have more than likely contracted the coronavirus at some point. Researchers then mathematically extrapolate those testing results to determine the extent of COVID transmission to provide this data.
The latest CDC data shows that 44.4 percent of all people tested had evidence of an infection. A larger proportion of young people have had COVID, the CDC data shows. As many as 66.5 percent of residents up to the age of 17 had evidence of COVID antibodies in their bloodstream, the CDC reports.
“These findings illustrate a high infection rate for the omicron variant, especially among children,” the CDC wrote in its report.
The state is well below the national average. The CDC said Tuesday that 75 percent of people under 18 nationwide had contracted the virus. For the total population, the CDC said 57.7 percent had contracted COVID-19.
“Connecticut historically has adopted more of a cautious approach to COVID compared to other states,” said Dr. Scott Roberts, associate director for infection prevention at Yale New Haven Hospital. “We are among the highest vaccinated states.”
The CDC said states with higher vaccination rates tended to have lower transmission, which Hartford HealthCare’s Dr. Ulysses Wu said made sense.
“The vaccine does protect you from infection to a certain extent,” he said.
The CDC conducts seroprevalence studies periodically, and the data shows a significant increase in transmission during the omicron wave. Roberts said Connecticut’s relative success is also due to better access to testing, stricter masking requirements and slower lifting of those mandates.
“I do think we performed at a better level than other states,” he said. “It’s surprising that so many people did get infected, but possibly speaks to Connecticut’s success compared to other states.”
On Wednesday, the state reported a seven-day positivity rate of 8.8 percent with 5,242 new cases out of 59,551 tests over the past week. There was a net increase of 41 hospitalizations in the past week for a total of 210, according to the state data.
Wu cautioned that the presence of antibodies does not indicate immunity. If the CDC’s numbers are accurate and more than 44 percent of the state has had COVID at least once, that does not mean those 1.5 million people are immune.
“They’re looking at total numbers,” he said. “When you take total numbers of people who have been infected, it has nothing to do with immunity. Immunity indicates a temporal factor that’s not included.”
And Roberts said the pandemic has been going on so long that some antibodies from infections early in the pandemic might not have been identified. He said seroprevalence studies offer a “snapshot.”
“A year and a half later, you might not have what they tested for,” he said. “If you had a recent infection, you probably would have a much higher antibody count.”
