Asymptomatic SARS-CoV-2 Carriers: A Systematic Review and Meta-Analysis

Abstract

Asymptomatic cases of SARS-CoV-2 can be unknown carriers magnifying the transmission of COVID-19. This study appraised the frequency of asymptomatic individuals and estimated occurrence by age group and gender by reviewing the existing published data on asymptomatic people with COVID-19. Three electronic databases, PubMed, Embase, and Web of Science (WoS), were used to search the literature following the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The study population for this review included asymptomatic individuals infected with SARS-CoV-2 reported in original articles published up to 30 April 2020. A random effects model was applied to analyze pooled data on the prevalence of asymptomatic cases among all COVID-19 patients and also by age and gender. From the meta-analysis of 16 studies, comprising 2,788 SARS-CoV-2 infected patients, the pooled prevalence according to the random effect size of asymptomatic cases was 48.2% (95% CI, 30–67%). Of the asymptomatic cases, 55.5% (95% CI, 43.6–66.8%) were female and 49.6% (95% CI, 20.5–79.1%) were children. Children and females were more likely to present as asymptomatic COVID-19 cases and could act as unknown carriers of SARS-CoV-2. Symptom-based screening might fail to identify all SARS-CoV-2 infections escalating the threat of global spread and impeding containment. Therefore, a mass surveillance system to track asymptomatic cases is critical, with special attention to females and children.

Seroepidemiology of SARS-CoV-2 infections in an urban Nicaraguan population

“…High seropositivity in children might be due to continued operation of public schools throughout the epidemic. As children are more likely to experience mild symptoms than adults, 11 this finding suggests that school-aged children may contribute to active transmission, and controlling infections in this sub-population is essential to reduce the spread of SARS-CoV-2. We also found that most individuals reported practicing strict physical distancing or masking behavior outside of the home, though this did not have a significant impact on the seroprevalence.…”

Anti-SARS-CoV-2 Antibodies Testing in Recipients of COVID-19 Vaccination: Why, When, and How?

“…Notably, a significant correlation has been observed between pre-vaccination anti-SARS-CoV-2 antibodies titer and Pfizer BNT162b2 vaccine immunogenicity, whereby the anti-SARS-CoV-2 RBD (receptor binding domain) total antibodies response seems to be reduced (up to nearly eightfold) in patients with a baseline antibody level in the upper quartile [11]. Therefore, with 50% (or even more) of all SARS-CoV-2 infections remaining completely asymptomatic up to negativization of molecular testing [14,15], the organization of pre-vaccination serological surveys represents a reliable mean for unmasking all SARS-CoV-2 seropositive subjects in whom vaccine administration may be personalized, adapted, or even delayed based on their actual anti-SARS-CoV-2 antibodies status [16]. This would also enable the optimization of vaccine administration to those who may benefit most (i.e., baseline anti-SARS-CoV-2 seronegative subjects), thus contributing to at least partially overcoming the current vaccines' manufacturing bottleneck, which is causing a worldwide shortage of doses, and thus perpetuating new outbreaks and the potential for emergence of new mutant strains.…”

Impaired Glucose-Insulin Metabolism in Multisystem Inflammatory Syndrome Related to SARS-CoV-2 in Children

“…During the pandemic children have been less affected than adults and SARS-CoV-2 was in most cases asymptomatic or with mild symptoms [3][4][5]. However, the development of a severe multisystem inflammatory syndrome in children (MIS-C) related to SARS-CoV-2 infection has been reported [6][7][8][9].…”