CDC study reveals that nursing home residents were re-infected with Covid’s worst case

A new CDC study found that some elderly people who apparently recovered from the coronavirus later contracted a second, even worse infection – indicating that asymptomatic or mild cases may not provide much protection against reinfection with Covid-19.

The study, published on Thursday in the weekly report from the Center for Disease Control and Prevention, Morbidity and Mortality, studied two separate outbreaks that occurred three months apart in a specialist ward in Kentucky. Between mid-July and mid-August, 20 residents and five health professionals tested positive for the virus, according to the study.

The second outbreak between late October and early December was worse – 85 residents and 43 health workers tested positive for the virus. Among the residents who tested positive during the first outbreak and still lived in the establishment, five of them tested positive for the second time, more than 90 days apart from the first positive test.

Although Covid-19 reinfections do occur, they are generally rare.

Through frequent surveillance after the first outbreak, all five residents had at least four negative tests between outbreaks, suggesting that they were potentially infected with the virus later, the study found. Reinfection means that a person who has had Covid-19 has recovered and obtained it again, according to the CDC.

“The exposure history, including the timing of roommate infections and the onset of symptoms during the second outbreak, suggests that the positive results of the second RT-PCR represented new infections after the patients apparently cleared the first infection,” wrote Alyson Cavanaugh, one of the researchers who conducted the study.

While only two of the five residents experienced mild symptoms during the first outbreak, all five potentially reinfected residents showed signs of illness the second time around. The two residents who reported symptoms during the first outbreak “experienced more severe symptoms during the second infectious episode,” according to the study. One resident was hospitalized and later died.

According to the study’s researchers, this was “noteworthy” because it suggests the possibility that people who have mild symptoms or none during their first infections “do not produce an immune response strong enough to prevent reinfection.” The results “suggest the possibility that the disease may be more severe during a second infection”.

“The results of this study highlight the importance of maintaining public health mitigation and protection strategies that reduce the risk of transmission, even among people with a history of COVID-19 infection,” wrote Cavanaugh.

The study noted some limitations. Because the samples were not stored, the researchers were unable to perform genomic sequencing, a laboratory technique that breaks the virus’s genetic code, to confirm reinfection, the researchers said. In addition, “no additional test results exist to support the initial test result as a true positive” during the first outbreak, they said.

The risk of reinfection for the general population is thought to be still low, but nursing home residents may be particularly at risk due to their coexistence and the high number of exposures, according to the study.

“Qualified nursing facilities should use strategies to reduce the risk of transmission of SARS-CoV-2 among all residents, including those who have already had a diagnosis of COVID-19, wrote Cavanaugh.