The number of patients who acquired Covid-19 while in the hospital jumped significantly in January—but several health experts say this increase was likely to be expected amid the omicron surge's record numbers.
How prevalent are hospital-acquired Covid-19 infections?
According to a study conducted by Epic, around 1.8% of Covid-19 hospitalizations were the result of infections patients acquired while hospitalized. For the study, researchers reviewed Covid-19 hospitalization data at 156 health care organizations between April 2020 and October 2021.
Overall, the researchers found that increases in hospital-acquired Covid-19 typically aligned with periods of high Covid-19 hospitalizations. A weekly peak in hospital-acquired Covid-19 cases reached 11,782 during the week ending Jan. 3, 2021.
In addition, the researchers noted that hospital-acquired Covid-19 cases decreased in the latter half of 2021, with the rate of patients who tested negative and then positive after admission rising only about half as much as overall Covid-19 admissions.
"We speculate increased vaccination rates among hospital staff, patients and visitors have contributed to a further limiting of the spread of Covid-19," they wrote.
However, a separate analysis of HHS hospitalization data by Politico found that the rates of hospital-acquired Covid-19 sharply increased as the highly transmissible omicron wave began spreading across the United States.
For Politico's analysis, researchers examined data between March 30, 2021 and Feb. 14, 2022, and found that 38 of the 40 days with the highest number of hospital-acquired Covid-19 cases occurred in 2022. Overall, more than 3,000 hospitalized patients were infected by the coronavirus each week in January—with a record 4,387 patients developing Covid-19 on the week ending Jan. 17.
According to Politico, HHS' data likely only shows a fraction of the total number of hospital-acquired Covid-19 infections since it only includes patients who were hospitalized for 14 consecutive days and does not account for people who test positive after being discharged.
Despite January's spike in hospital-acquired Covid-19 cases, both federal and state health officials said the risk of being infected at a hospital remains relatively low.
For example, a spokesperson from North Carolina's health department said 1.6% of patients contracted Covid-19 while in the hospital in December 2021, and this rate increased to 2.2% in January. In December, an average of 25 patients acquired Covid-19 infections each day, while an average of 96 patients were infected each day in January.
In addition, several public health experts said that the increase in hospital-acquired Covid-19 cases was to be expected as both cases and hospitalizations increased to record numbers during the omicron surge.
"A hospital is a subset of the population," said Kathleen Gallagher, an epidemiologist at the National Patient Advocate Foundation. "You'd expect to see that increase."
"At the time, home tests were scarce, lines were hours long for in-office testing, and other changes were going on, like CDC changes to health care worker quarantine procedures,” she added. "People visiting patients were potentially not required to show proof of vaccination, and may not have worn the right masks or worn them improperly."
Separately, Shama Cash-Goldwasser, senior technical adviser at Resolve to Save Lives, said it's impossible to completely eradicate coronavirus transmission, particularly when facilities are crowded and staff are overwhelmed during Covid-19 surges.
"It's unfortunate," she said. "I'm not saying it's OK ... Immunocompromised patients and very sick people are at very high risk of poor outcomes, so transmission inside a hospital can really be devastating." (Levy/Vestal, Politico, 2/19; Muoio, Fierce Healthcare, 2/8; Howard et al., Epic Research, 2/7)