COVID transmission and contact tracing using WHO risk assement tool among frontline healthcare workers : Insights from a South Indian tertiary care centre

Moni, M.; Kulirankal, K. G.; Prasanna, P.; Mary, A.; Thomas, E. M.; Sundaram, R. P.; Babu, B.; Bindu, V.; Edathadathil, F.; Bala, S.; K V, B.; Sathyapalan, D. T.

Background: The high exposure risk to COVID among frontline healthcare workers was a major challenge to healthcare systems across the globe that warranted close monitoring through risk assessment and contact tracing strategies. The objective of our study was to characterize exposure risk factors for transmission and subsequent COVID positivity among the frontline healthcare workers in our institution during the pandemic period. Methods: The retrospective observational study conducted over a period of 6 months from June 2020 to November 2020 at a 1300-bedded South Indian tertiary care centre included frontline healthcare workers who were assessed for their identified encounter with COVID positive individual using a modified WHO COVID risk assessment tool. Results: Among a total of 4744 contacts with COVID positive individuals assessed for risk stratification during the study period , 942 (19.8%) were high risk and 3802 (80.2%) were low risk exposures respectively. 106 (2.2%) turned COVID positive during the surveillance period of 14 days. Frontline workers working in COVID areas had significant low COVID rates as compared to other areas (N=1, 0.9%). The average monthly COVID positivity rates being 1.66%, the attack rates among high risk and low risk contacts among the total HCWs screened were 5% (46/942) and 1.57% (60/3802) respectively. Shared space (70%) and IPC breaches (66%) were found to be highly prevalent in the COVID positive cohort, along with maskless encounters (43%) and multiple exposure (39%). The attack rate among the 6 identified COVID cluster groups (5.5%) were found to be higher than the attack rate (2.2%) noted among the total contacts screened and no significant association was observed between risk categories in the clusters. Discussion: Our study highlights higher risk of COVID positivity among high risk contacts as compared to low risk contacts. However, the high COVID positivity rate in low risk group among cluster transmissions and its lack of association with risk assessment highlight the suboptimal utility of the risk assessment strategy among cluster groups.