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

bhattacharya, b.; Kumar, R.; Meena, D. V. p.; Soneja, M.; Vig, S.; Rastogi, V.; Bhatnagar, S.; Mohan, A.; Wig, N.

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 : 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 & >4 weeks of illness. 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.