—For every 10,000 confirmed COVID-19 cases, there are approximately 4.3 recurrent cases, according to a study published online May 4 in PLOS ONE.
Ithan D. Peltan, M.D., from Intermountain Healthcare in Salt Lake City, and colleagues used clinical assessment and laboratory data to assess the incidence of a recurrent positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcription-polymerase chain reaction (RT-PCR) assay ≥60 days after an initial positive test. The analysis included 23,176 patients with an initial positive test for SARS-CoV-2 between March 11 and July 31, 2020.
The researchers found that 1,301 patients (5.6 percent) initially testing positive had at least one additional SARS-CoV-2 test 60 or more days later. Among 122 patients who tested positive, 114 had sufficient data for evaluation, which showed a median interval to the recurrent positive test of 85.5 days. Overall, four of 122 patients met criteria for probable COVID-19 recurrence when combining clinical and RT-PCR cycle threshold data. At recurrence, all four patients exhibited symptoms and three required a higher level of medical care compared with their initial diagnosis. Six additional patients had possible recurrence. Combining probable and possible recurrences yielded a recurrence incidence of 4.3 cases per 10,000 COVID-19 patients.
“We urgently need to understand the epidemiology of recurrence,” Peltan said in a statement. “We hope that our method will be helpful as a framework for categorizing potential recurrence cases as the number of recovered COVID-19 patients rises, immunity wanes, variants spread, and more reinfection cases occur.”
Several authors disclosed financial ties to the pharmaceutical industry.