Five residents of a skilled nursing facility in Kentucky tested positive twice for SARS-CoV-2 in two separate outbreaks three months apart, a study by public health officials has found

The outbreaks occurred in 2020, before COVID-19 vaccinations were available. All five residents had received at least four negative test results between the two outbreaks, suggesting the possibility of reinfection, according to researchers from the Kentucky Department for Public Health and the Centers for Disease Control and Prevention. What’s more, the disease course in these residents was more severe the second time around, and one of the ill residents died.

During the first outbreak, three of the five were asymptomatic and the other two had mild symptoms that resolved before the second outbreak. Test samples were not kept, so determining the genetic strain of the virus during each outbreak was not possible, the researchers said.

COVID-19 reinfections have been noted but deemed rare by researchers worldwide. A newly published study from the National Institutes of Health showed that COVID-19 survivors appear to be well protected against reinfection for at least a few months. But the Kentucky findings highlight the need for continued infection control vigilance in long-term care, researchers in the current study said.

“Skilled nursing facilities should use strategies to reduce the risk for SARS-CoV-2 transmission among all residents, including among those who have previously had a COVID-19 diagnosis,” the authors concluded.