Hospital-acquired COVID-19 infections were rare through fall 2021, Epic data show

Hospital-developed COVID-19 cases represent about 1.8% of COVID-19 hospitalizations and were potentially on the decline by the tail end of the pandemic’s delta wave, according to a patient data analysis conducted by electronic health record vendor Epic.  

The review of 156 healthcare organizations’ COVID-19 hospitalizations through October 2021 found upticks of in-hospital COVID-19 transmission to generally fall in line with periods of high COVID-19 admissions.

These hospital-developed COVID-19 infections—defined as hospitalized patients who tested negative on the day of or day after admission but then tested positive six or more days later—reached its peak on the week of Dec. 6, 2020, with 172 such cases.

Overall, COVID-19 hospitalizations at the same collection of facilities hit their peak of 11,782 weekly hospitalizations about a month later. For context, nationwide weekly COVID-19 hospitalizations as measured by the Centers for Disease Control and Prevention during that same week came in just over 17,000.

“When we looked at the data over time, we found that these cases of COVID-19 rose and fell in similar patterns to the number of patients admitted due to COVID-19 infection,” Epic-employed clinicians and research scientists wrote in their report. “However, in the last half of 2021, the rate of patients who tested negative and then positive after admission rose only about half as much as overall COVID-19 admissions. We speculate that increased vaccination rates among hospital staff, patients and visitors have contributed to a further limiting of the spread of COVID-19.”

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The analysis was conducted and affirmed by two separate Epic research teams reviewing COVID-19 cases across the company’s nationwide Cosmos data set, which includes limited information on 126 million patients across 889 hospitals and 19,420 clinics.

The low rate of hospital-developed COVID-19 infections suggest the public’s fear of seeking care at hospitals or emergency departments throughout much of the pandemic was “likely unfounded,” the team wrote.

Still, they acknowledged that the numbers could be an undercount, due to patients who may have been discharged prior to testing positive for COVID-19 contracted during their stay, as well as an overcount, due to potential false negatives upon admission.

Fear of COVID-19 infection during care—in tandem with government-ordered lockdowns or temporary service line closures—led many patients to defer care during the early months of the pandemic and beyond.

Industrywide analyses and quarterly reports have shown steady patient volume recovery in the months since, although the numbers still lag what hospitals were seeing in 2019.