The CDC said it studied two separate outbreaks that occurred three months apart at a nursing facility in Kentucky. Over the summer, 20 residents and five staff members contracted COVID-19. Then between October and December, 85 residents and 43 health-care personnel tested positive for the virus.
Five of those residents tested positive for COVID-19 in both the first and second outbreak. The reinfection occurred more than 90 days after their first positive test.
“The exposure history, including the timing of roommates’ infections and the new onset of symptoms during the second outbreak, suggest that the second positive RT-PCR results represented new infections after the patients apparently cleared the first infection,” wrote Alyson Cavanaugh, one of the researchers who led the study.
Immune response could play a role
Health officials said several residents who came down with the virus a second time experienced more severe symptoms.
“Although three of the five patients with recurrent COVID-19 were asymptomatic during their first infectious episode, all five experienced symptoms during their second infectious episode; the two patients who were symptomatic during the first outbreak experienced more severe symptoms during the second infectious episode compared with the symptoms they had during the first outbreak,” the CDC wrote. “One resident patient required hospitalization and subsequently died.”
The researchers said the study suggests that it’s possible for people with symptoms that are either mild or nonexistent to the first time they get COVID-19 to later get a worse case of the virus because they “do not produce a sufficiently robust immune response to prevent reinfection.”
Reinfection possible
The study results “suggest the possibility that disease can be more severe during a second infection,” the CDC said.
“The findings of this study highlight the importance of maintaining public health mitigation and protection strategies that reduce transmission risk, even among persons with a history of COVID-19 infection,” Cavanaugh wrote.
Throughout the pandemic, nursing home residents have been particularly vulnerable to catching the virus due to the fact that they live in close proximity to others. The study authors said nursing facilities should continue to use strategies to reduce the spread of the virus, “including among those who have previously had a COVID-19 diagnosis.”