DETECTION OF SARS-CoV-2 IN ASYMPTOMATIC CLOSE CONTACTS OF CASES CONFIRMED BY MOLECULAR DIAGNOSIS, BUENOS AIRES PROVINCE, ARGENTINA

Abstract

The detection of SARS-CoV-2 and its implication in the diagnosis of COVID-19 have been highly debated in the pandemic. Access to molecular diagnosis and its target population was essential in the public policy. The objective of this study was to evaluate the cost / benefit of detecting SARS-CoV-2 in asymptomatic close contacts using different molecular diagnostic tests. 51 close contacts of people with a diagnosis of SARS-CoV-2 confirmed by RTqPCR, classified by Ct (<20, between 20 and 30 and> 30), were studied in public hospitals in Province of Buenos Aires. Of all contacts studied, 15.7% were confirmed for SARS-CoV-2, there were no contacts of cases with Ct> 30 positive. The number of positive contacts of cases with Ct <20 was significantly higher than that of cases with Cts> 20. Samples with Cts <20 were associated with an estimated viral load of 1 to 4 orders of magnitude difference with Ct ranges> 20. 13.7% of positive close contacts were from cases with Ct <20. When studying positive samples with confirmed diagnosis by PCR, corresponding to EW1 of 2021, only 19.35% corresponded to samples with Cts <20 and 50.7% with Cts between 20 and 30. From these data it is shown that with the close contact test we could detect only 3.7% of cases. The effort by the public health system for this strategy, with low predictive power, may have a negative effect on the fulfillment of the isolation of contacts and could generate a delay in the results of suspected cases, without contributing significantly to controlling the pandemic.