Close contacts tracing of patients with covid -19 in jazan region, ksa, may 2020.

Background: As of May 15, 2020, the global reported number of COVID-19 cases has crossed over 4.5 million with more than 303,000 deaths. The possibility of presymptomatic and asymptomatic transmission of SARS-CoV-2 is increasing the challenges of COVID-19 control measures. Methods: Based on a comprehensive contact-tracing dataset documented through the Quarantine Department in Jazan Region during the period from March 16 up to May 15, 2020, secondary data was reviewed to determine the secondary attack rate of SARS-CoV-2 among close contacts of index cases. The respiratory and non-respiratory symptoms effects on transmissibility and the infectivity of COVID-19 cases were assessed. Results: A total of 400 primary cases and 1167 close contacts were quarantined and traced as well. The overall secondary attack rate among close contacts of index cases with COVID-19 was 35.6% (416), while the secondary attack rate among close contacts of asymptomatic primary cases was 10%(44), which are relatively low when compared to the 51.2% (372) figure that represents the secondary attack rate among close contacts of symptomatic index cases. The study also revealed that primary cases with respiratory symptoms transmitted the infection to 67.8% of their close contacts while index cases with non-respiratory symptoms infected only 47%. The age bracket mostly affected was 25 to 49 years of age. The secondary attack rate was 82% among males compared to only 18% of females who tested positive, reflecting significant association between transmission of infection and gender (p-value0.000). This may be attributed to the fact that Saudi females always wear veils outdoors and these religious face covers might play a role against COVID-19, a perspective for which further study is highly recommended. Conclusion: SARS-CoV-2 was found to be less transmissible from asymptomatic patients (10. %) as compared to high rates of secondary attack among close contacts of symptomatic index cases (51.2%), with the age group (25 up to 49 years) being the most vulnerable to COVID-19 transmission. Although early detection and isolation of index cases and their close contacts, in addition to the movement restrictions play a major role to control the pandemic, the challenge for pandemic containment remains in identifying cases during the presymptomatic phase.