Rates of recurrent positive SARS-CoV-2 swab results among patients attending primary care in Qatar

Abstract

We read with interest the work of COCOREC (Collaborative study COvid RECurrences) study group.1 Recurrent positive rt-PCR results for SARS-CoV-2 infection were reported from early in the epidemic.1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 Viral genomic sequences provided concrete evidence for reinfection by distinct SARS-CoV-2 infection.9 , 10 , 11 , 12 The number of days in between both infections in viral genomic proven reports ranged from 48 to 142 days. While viral genomic sequencing provides robust evidence, it does not lend itself well to everyday practice. The COCOREC study identified 11 cases of reinfection using well-defined criteria.1 The group suggested recurrent positive rt-PCR results of more than 21 days following the resolution of symptoms as criteria for reinfection. The criteria though less specific, are more feasible to use in primary health care settings. Utilising the criteria set by the COCOREC study group, this record-based study reports on the cases with recurrent positive RT-PCR nasopharyngeal swab for SARS-CoV-2 results in primary health care corporation (PHCC) settings in Qatar. PHCC is the largest primary care provider in Qatar with 27 health centers covering all the country. The organisational employs an electronic medical record (EMR), which links all public primary health care centers. For this study, all electronic data were extracted from the primary healthcare setting visits, and no sampling was needed. The study population included patients attending with documented SARS-CoV-2 rt-PCR results during the study period. The study period was from February 10th, 2020, to July 30th, 2020, a total of 171 days. The recurrent positive population included all patients with a minimum number of 2 positive swabs and a minimum number of 21 days in between positive swab results. Inconclusive and reactive rt-PCR results were considered negative. During the study period, patients were entitled to a repeat swab if they are attending with new symptoms following the resolution of initial symptoms. A maximum number of days in between any positive swab results was calculated for those who met our definition criteria. The study aims to answer the following questions. What is the maximum number of days in between positive swab results? What are the rates of recurrent rt-PCR SARS-CoV-2 positive results of more than 21 days, and what are the population characteristics?