CHARLOTTESVILLE, Va. (WDBJ / UVA Release) – UVA researchers have concluded that herd immunity in Virginia “is not currently a plausible means of ending the COVID-19 pandemic.” But they believe their finding underscores the importance of vaccines and say that without them, the herd’s immunity is so much farther away.
The finding is based on a study in which statewide blood tests for COVID-19 found that only 2% of Virginians had antibodies to the virus as of mid-August 2020, just months after the pandemic started and before vaccines were available.
Read the entire study here.
According to UVA researchers, about 2.8 times more Virginians had antibodies than identified by the state’s PCR tests. That ratio is lower than many estimates predicting how much of the country’s population may already have COVID-19 antibodies.
Participants in the Hispanic study had the highest exposure, according to UVA, with more than 10% with antibodies. Other groups with “significantly higher” rates included residents of Northern Virginia (4.4%), people ages 40 to 49 (4.4%), and the uninsured (5.9%). The prevalence by postal code ranged from 0% to 20%. Often times, neighboring zip codes yielded dramatically different results, the researchers say.
“We are closely monitoring the number of cases, but we must recognize that the number of cases is an underestimate of the true number of COVID infections,” said Eric Houpt, MD, chief of UVA Health’s division of Infectious Diseases and International Health. “Using this data to project to today, we would predict that as of February 2021, less than 20% of Virginians will still be exposed to the virus.”
COVID-19 antibody test
To better understand how widespread COVID-19 is in Virginia, UVA Health and the Virginia Department of Health worked with major hospitals across the state. The researchers tested the blood of 4,675 outpatients in five health systems: UVA Health in the Northwest, Inova Health System in the North, Sentara Healthcare in the East, Carilion Clinic in the Southwest, and Virginia Commonwealth University in the center. Each site enrolled up to 1,000 residents 18 years of age or older who were not evaluated for possible COVID-19 infections. According to UVA, the participants matched the age, race, and ethnicity of each region
Of the 101 participants who were found to have COVID-19 antibodies, 42 were Hispanic. People with antibodies were more likely to live in multifamily wards and interact with a patient confirmed to have COVID-19, the researchers report.
The researchers estimate that about 66% of the infections detected were asymptomatic.
Previous COVID-19 studies have suggested that confirmed cases represent only a small percentage of people infected. Estimates of total unrecognized infections ranged from six times the confirmed cases to 53 times, so the results from Virginia were lower by comparison, according to UVA.
“Virgos are still very susceptible to this virus,” said Houpt. “We have to keep wearing masks in public and social distance and wash hands. I encourage everyone who qualifies to get a COVID vaccine if possible. “
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