SARS-CoV-2 RT-PCR profile in 298 Indian COVID-19 patients: a retrospective observational study

Background: despite being in the 5th month of pandemic, knowledge with respect to viral dynamics, infectivity and RT-PCR positivity continues to evolve. Aim: to analyse the SARS CoV-2 nucleic acid RT-PCR profiles in COVID-19 patients. Design: it was a retrospective, observational study conducted at COVID facilities under AIIMS, New Delhi. Methods: patients admitted with laboratory confirmed COVID-19 were eligible for enrolment. Patients with incomplete details, or only single PCR tests were excluded. Data regarding demographic details, comorbidities, treatment received and results of SARS-CoV-2 RT-PCR performed on nasopharyngeal and oropharyngeal swabs, collected at different time points, was retrieved from the hospital records. Results: a total of 298 patients were included, majority were males (75·8%) with mean age of 39·07 years (0·6–88 years). The mean duration from symptom onset to first positive RT-PCR was 4·7 days (SD 3·67), while that of symptom onset to last positive test was 17·83 days (SD 6·22). Proportions of positive RT-PCR tests were 100%, 49%, 24%, 8·7% and 20·6% in the 1st, 2nd, 3rd, 4th and >4 weeks of illness. A total of 12 symptomatic patients had prolonged positive test results even after 3 weeks of symptom onset. Age > = 60 years was associated with prolonged RT-PCR positivity (statistically significant). Conclusion: this study showed that the average period of PCR positivity is more than 2 weeks in COVID-19 patients; elderly patients have prolonged duration of RT-PCR positivity and requires further follow up.