SARS- CoV-2, also known as the Covid- 19 virus, causes an acute respiratory infectious disease. Humans are generally susceptible. The main source of infection is currently people infected with the virus, even those who have an asymptomatic course. According to recent epidemiological studies, the incubation period varies from 1 to 14 days, but most commonly from 3 to 7 days. Typical symptoms at manifestation include fever, fatigue, and dry cough. Among others, rhinorrhea, sore throat, myalgias & diarrhea symptoms may occur in rare cases.
Pandemic can only be contained by interrupting the transmission of infection. Considering that most transmission is caused by asymptomatic virus carriers, systematic and repeated screening of the population has a very special role. Without screening, we deprive ourselves of the opportunity to prevent further de-escalation.
Symptomatic and Asymptomatic Virus Carrier
A study of 303 SARS-CoV-2 patients (89 of whom were persistently symptom-free), symptomatic and asymptomatic infected individuals had similar Ct values in PCR during the course, meaning they released comparable amounts of viral RNA.¹ In another study published on behalf of the British Geriatric Society, the authors concluded that systematic prevalence testing is needed, particularly in the nursing home sector, to reduce the risk of transmission by asymptomatic carriers and to manage outbreaks in this setting. ² Asymptomatic SARS-CoV-2 virus carriers have a similar viral load to symptomatic patients. Therefore, isolation of infectious individuals must occur regardless of signs of illness. Screening is used to ensure this, or to move one step closer to this goal, which has not seemed feasible until now due to the insufficient area-wide capacity of PCR testing.
1. Lee S, Kim T, Lee E, et al. Clinical Course and Molecular Viral Shedding Among Asymptomatic and Symptomatic Patients With SARS-CoV-2 Infection in a Community Treatment Center in the Republic of Korea. JAMA Intern Med. Published online August 06, 2020. doi:10.1001/jamainternmed.2020.3862
2. Sean P Kennelly, Adam H Dyer, Claire Noonan, Ruth Martin, Siobhan M Kennelly, Alan Martin, Desmond O’Neill, Aoife Fallon, Asymptomatic carriage rates and case-fatality of SARS-CoV-2 infection in residents and staff in Irish nursing homes, Age and Ageing, , afaa220,