CHARLOTTESVILLE, Virginia (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 discovery underscores the importance of vaccines, saying that without them, the herd’s immunity is much further.
The finding is based on a study in which state blood testing for COVID-19 found that only 2% of virgins had antibodies to the virus since mid-August 2020, just months after the pandemic began and before vaccines became available. .
Read the full study here.
According to UVA researchers, about 2.8 times more virgins had antibodies than were identified by state PCR testing. This ratio is lower than many estimates that predict how much of the country’s population may already have COVID-19 antibodies.
Hispanic study participants had the highest exposure rate, according to UVA, with more than 10% having antibodies. Other groups with “significantly higher” rates included residents of North Virginia (4.4%), those aged 40 to 49 (4.4%) and the uninsured (5.9%). The prevalence by zip code ranged from 0% to 20%. Neighboring zip codes have often produced dramatically different results, the researchers say.
“We are closely monitoring the number of cases, but we must recognize the number of cases is an underestimation of the actual number of COVID infections,” said Eric Houpt, MD, head of the UVA Health Division of Infectious Diseases and International Health. “If we use this data to project ourselves today, we would project that as of February 2021, less than 20% of Virginians could have been exposed to the virus.”
COVID-19 antibody testing
To better understand how widespread COVID-19 was in Virginia, UVA Health and the Virginia Department of Health collaborated with major hospitals in the state. The researchers tested the blood of 4,675 outpatients at 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, aged 18 or older, who were not evaluated for potential 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 units and had contact with a patient confirmed to have COVID-19, the researchers report.
The researchers estimated that about 66% of the infections detected were asymptomatic.
Previous COVID-19 studies have suggested that confirmed cases may represent only a small percentage of infected individuals. Estimates of total unrecognized infections ranged from six-fold confirmed cases to 53-fold, so results in Virginia were lower compared to UVA.
“Virginians are still quite sensitive to this virus,” Houpt said. “We must continue to wear masks in public and practice social distancing and hand washing. I encourage everyone who qualifies to receive a COVID vaccine when they can. ”
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