Health

Nearly Half Of All Hospitalized Patients With COVID-19 Had Only Mild Or Asymptomatic Cases, Study Shows

(Photo by OMAR HAJ KADOUR/AFP via Getty Images)

Dylan Housman Healthcare Reporter
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Almost half of VA hospitalized COVID-19 cases across the United States have been asymptomatic or mild, according to a new study from researchers at Harvard Medical School, Tufts Medical Center and the Veterans Affairs Healthcare System.

The new study examined record from almost 50,000 COVID-19 hospital admissions to more than 100 VA hospitals across America. The researchers found that in the pre-vaccination, pre-Delta variant era of the pandemic, from March 2020 to January 2021, 36% of hospitalized patients had a mild or asymptomatic infection. From January 2021 to the end of June 2021, however, the proportion rose to 48%.

Outcomes were better for the vaccinated than the unvaccinated: 57% of vaccinated hospitalized patients had mild or asymptomatic cases, compared to 45% for the unvaccinated. Dr. Shira Doron of Tufts Medical Center, who worked on the project, said that the high proportion of non-serious unvaccinated cases may be due to less young people being vaccinated, or more people who have some level of natural immunity being unvaccinated.

The population of patients at VA hospitals is not representative of the U.S. populace as a whole, but prior pediatric studies support the findings as well. The researchers behind the new paper defined mild cases as those that did not require oxygen supplementation or reach a blood oxygen level below 94%. (RELATED: Nearly 60% Of Americans Support Biden’s Vaccine Mandates, Poll Shows)

Hospitalizations have been a key metric for health experts in gauging the severity of the pandemic. It can be preferable to death counts, which are a lagging indicator and do not account for serious cases that are survived, or case counts, which can fluctuate based on testing regimes and frequency. (RELATED: ANALYSIS: Biden Said He’d Shut Down The Virus. Now The Pandemic Has No End In Sight)

However, prior to this study, little comprehensive research had been done to determine what proportion of hospitalized cases are severe or life-threatening. The federal government requires states and localities to report all hospitalized COVID-19 cases under one category, regardless of severity, and many hospitals test patients admitted for any reason for COVID-19 as well. If those patients happen to also have COVID-19 they are typically counted as a COVID-19 hospitalization even if that isn’t the reason for their hospitalization, leading to the substantial number of asymptomatic hospitalizations.