LAUSR

Background: SARS CoV 2 is a new Beta coronavirus subgenus Sarbecovirus, family Coronaviridae Causing pandemic of coronavirus disease 2019(COVID 19) • It spread rapidly causing severe global public health crisis. • Transmitted mainly by respiratory droplets, it causes atypical pneumonia and acute respiratory distress syndrome. • RT PCR is the recom- mended test by ICMR for surveillance of COVID 19. • According to WHO total cases in India is around 8.96million and deaths around 1, 32000(2%). Methods:Nasopharyngeal and oropharyngeal swabs collected over a period of 8 months from April to November 2020 were subjected to RT PCR by ICMR approved RTPCR kits. Results: Among 1, 84,915 samples tested, 19,431 (10.5%) were positive for COVID 19 and 1, 64,802 (89.14%) were nega- tive. 682 samples (0.36%) were rejected out of which 132(0.07%) were rejected pre analytically and 550 (0.29%) post analytically. Males (64%) were affected more than females (36%). Peak incidence was found between 20 -40 years of age (73%) and Co-morbidity in 15% of cases. Maximum Positivity rate of 29.8% was observed in June and thereafter a steady decline was observed. Conclusions: This study conducted in North Chennai recognized as Red zone of Tamil Nadu in April 2020shows a gradual increase in positive cases with peaking in June 2020(29.8%) unlike the peaking seen in September in rest of India. A steady decline to 4.1% was noted in the following months. Due to effective containment measures of Government by legally mandated quarantine, active surveillance of cases and controls with early diagnosis and isolation, barricading of hotspots, mandatory face masks, social distancing, hand sanitation and cough etiquette, positivity rate declined in the last 4 months even after lifting the lockdown. The challenges we face in diagnosis and treatment of COVID19 emphasize the need to promote research and development, strengthening drug and vaccination development programs and evolv- ing a robust action plan to face a pandemic.