Public health implications of transmissions during asymptomatic period
According to different kinds of literature and scientific pieces of evidence, the existence of persons with asymptomatic SARS-CoV-2 infection who are capable of transmitting the virus to others has so many implications. Because many SARS-CoV-2 cases are recovering without showing signs and symptoms (29), the attack rate and case-fatality rates of COVID-19 might be lower or inaccurate related to currently estimated ratios, if asymptomatic SARS-CoV-2 infections are included (30, 31). This is the first implication that should be introduced during the surveillance and reporting of SARS-CoV-2 in each country. The second and the very important implication to slow the transmission of COVID-19 is transmission while asymptomatic reinforces the value of community interventions. Clearly understanding of the asymptomatic transmission is possible and even risk. Center for Diseases Prevention and Control (CDC) and WHO recommended that the very important intervention method is physical distancing(32, 33), use of face-covering materials like cloth in public places (34), and universal masking in healthcare facilities(35) to prevent SARS-CoV-2 transmission by asymptomatic and symptomatic persons. Third but might not be the final implication of asymptomatic transmission is that it could enhance the need to increase the capacity for widespread testing and thorough contact tracing to detect asymptomatic infections, interrupt undetected transmission chains, and further curve down the epidemic curve. Contact tracing (36-38), and implementation of multipronged surveillance and containment measures(39) are the key approaches for limiting the transmission rate.