The incidence of the novel coronavirus SARS-CoV-2 among asymptomatic patients: A systematic review

Abstract

Background: The recent outbreak of the coronavirus disease 2019 (COVID-19) has quickly spread globally since its discovery in Wuhan, China, in December 2019. A comprehensive strategyincluding surveillance, diagnostics, research, and clinical treatmentis urgently needed to win the battle against COVID-19. Recently, numerous studies have reported the incidence of SARS-CoV-2 in asymptomatic patients. Yet, the incidence and viral transmission from the asymptomatic cases are not yet apparent. Aim: To estimate the incidence of COVID-19 among asymptomatic cases and describe its epidemiological and clinical significance this review systematically examined the published literature on SARS-CoV-2 in asymptomatic patients. Methods: The literature was searched through four scientific databases: PubMed, Web of Science, Scopus, and Science Direct. Results: Sixty-three studies satisfied the inclusion criteria. The majority of the reported studies were from China. However, there was a lack of SARS-CoV-2 epidemiological studies, from several countries worldwide, tracing the actual incidence of COVID-19, especially in asymptomatic patients. Studies with a large sample size (>1000) estimated that the percentage of people contracting SARS-CoV-2 and likely to be asymptomatic ranged from 1.2-12.9%. However, other studies with a smaller sample size reported a much higher incidence and indicated that up to 87.9% of COVID-19 infected individuals could be asymptomatic. Most of these studies indicated that asymptopatics are a potential source of infection to the community. Conclusion: This review highlighted the need for more robust and well-designed studies to better estimate COVID-19 incidence among asymptomatic patients worldwide. Early identification of asymptomatic cases, as well as monitoring and tracing close contacts, could help in mitigating the spread of COVID-19.

Evaluation of SARS-CoV-2 IgG antibody response in PCR positive patients: Comparison of nine tests in relation to clinical data

“…This makes the diagnosing of previous COVID-19 patients by antibody test more difficult in asymptomatic and pauci-symptomatic patients since the sensitivity of several tests is much lower in this subgroup than in highly symptomatic group. Since the majority of COVID-19 patients are asymptomatic or have only a few mild symptoms the sensitivity of antibody tests to detect disease in the general population could be lower [ 8 ]. This may affect the reliability of antibody-based epidemiological studies.…”

“…However, other studies have failed to find any correlation between clinical course and immune response [ 3 , 6 ]. Since the majority of COVID-19 cases are asymptomatic, the performance of the tests in this group is important to evaluate the reliability of antibody tests in seroepidemiological studies and clinical diagnostics [ 8 ].…”

Asymptomatic COVID-19 in hospital visitors: The underestimated potential of viral shedding

“…There was close contact between them before and during hospitalization. One possibility is that transmission happened beforehand, since longer incubation periods and transmission from asymptomatic individuals have been reported [1] . Although it is not possible to completely exclude transmissions related to other patients or hospital staff [1] , [2] , [3] , [4] , no other contacts developed symptoms before or afterwards.…”

“…The burden of asymptomatic Coronavirus Disease-2019 (COVID-19) on clinical practice and epidemiological control remains a challenge, especially due to high potential of transmission [1] , [2] . While several nosocomial outbreaks have been reported [2] , [3] , most studies focused on the role of asymptomatic hospitalized patients [4] , [5] .…”

When Should Asymptomatic Persons Be Tested for COVID-19?

“…The asymptomatic and pre-symptomatic phases of SARS-CoV-2 infection make it impossible to rely on symptom-based contact tracing alone. Published studies suggest that up to 45% of individuals infected with SARS-CoV-2 can be asymptomatic (18,19). Symptomatic individuals with COVID-19 and asymptomatic individuals without known exposure may have similar levels of detectable virus, suggesting equal infectivity (20,21).…”