According to a recent study on widespread vaccination, the number of COVID-19 hospitalizations in the United States may have included patients with mild or incidental diagnoses that are unrelated to the coronavirus.
The study, posted on Research Square, pointed out that in the early days of the pandemic, COVID-19 cases were strongly correlated with hospitalizations, and both were reflective of the disease burden and community risk.
But since widespread vaccine availability, these metrics have become increasingly uncoupled, as reflected by the falling proportion of admissions with moderate-to-severe COVID-19. The uncoupling is more pronounced in fully vaccinated individuals, who continue to be strongly protected against severe disease.
The study found that among more than 47,700 admissions with laboratory-confirmed COVID-19, more than 28,700 met the criteria for moderate-to-severe COVID-19. It means that almost half of the hospitalized patients only displayed mild symptoms, suggesting that they were likely admitted due to reasons unrelated to COVID.
“With widespread vaccination, the current definition of COVID-19 hospitalizations includes progressively more mild or incidental diagnoses, for example, cases identified prior to surgery or prior to discharge, rather than hospitalizations due to severe COVID-19,” the study’s authors said.
The study echoes other recent research that also found the current definitions of “COVID-19 hospitalizations” combined with routine, and often mandatory, screening testing of all admissions may substantially overestimate the number of hospitalizations caused by COVID-19 infection.
In a pediatric population, 41% of reported admissions associated with COVID-19 infection were for reasons other than COVID-19.
With the findings, the authors suggested that the CDC should consider updating the definition of COVID-19 hospitalizations to reflect better cases of hospitalization caused by COVID-19 versus hospitalizations associated with detection of COVID-19.