SARS-CoV-2—Morphology, Transmission and Diagnosis during Pandemic, Review with Element of Meta-Analysis

Abstract

The outbreak of Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2). Thus far, the virus has killed over 2,782,112 people and infected over 126,842,694 in the world (state 27 March 2021), resulting in a pandemic for humans. Based on the present data, SARS-CoV-2 transmission from animals to humans cannot be excluded. If mutations allowing breaking of the species barrier and enhancing transmissibility occurred, next changes in the SARS-CoV-2 genome, leading to easier spreading and greater pathogenicity, could happen. The environment and saliva might play an important role in virus transmission. Therefore, there is a need for strict regimes in terms of personal hygiene, including hand washing and surface disinfection. The presence of viral RNA is not an equivalent of active viral infection. The positive result of the RT-PCR method may represent either viral residues or infectious virus particles. RNA-based tests should not be used in patients after the decline of disease symptoms to confirm convalescence. It has been proposed to use the test based on viral, sub-genomic mRNA, or serological methods to find the immune response to infection. Vertical transmission of SARS-CoV-2 is still a little-known issue. In our review, we have prepared a meta-analysis of the transmission of SARS-CoV-2 from mother to child depending on the type of delivery. Our study indicated that the transmission of the virus from mother to child is rare, and the infection rate is not higher in the case of natural childbirth, breastfeeding, or contact with the mother. We hope that this review and meta-analysis will help to systemize knowledge about SARS-CoV-2 with an emphasis on diagnostic implications and transmission routes, in particular, mother-to-child transmission.

Progress in the Diagnosis and Treatment of COVID-19 in Children: A Review

“… 3 , 16 At the same time, there are reports showing that viruses can be cultivated from wastewater samples, which suggests a possible water transmission route. 17 Starting from the newborn, children of all ages are likely to be infected with COVID-19. 18 Existing data show that the main source of infection for children is SARS-CoV-2-positive adults living in the family.…”

“… 20 In general, compared with adults, children are less likely to transmit SARS-CoV-2, 21 and children are less susceptible to SARS-CoV-2 with longer incubation period and viral excretion time in feces. 17 Children have fewer outdoor activities and fewer international travels, and the virus infection rate may be reduced accordingly. 22 Data also show that children under 5 years of age are less likely to be infected with SARS-CoV-2 than children over 5 years of age, though there is no clear reason for this finding.…”

COVID-19 in a Pre-Omicron Era: A Cross-Sectional Immuno-Epidemical and Genomic Evaluation

“…It is also possible to observe that despite the phylogenetic difference between these two variants, they have approximately the same divergence. In this context, a relevant factor for the emergence of new viral variants is selective pressure caused by the abuse of antiviral drugs without proven efficacy [ 32 , 33 ].…”

Efficacy of mouthrinses in reducing oral SARS-COV-2 load: a review

“…1 The main route of transmission of SARS-CoV-2 is from person to person through small respiratory droplets, when a contaminated person coughs, sneezes, or talks. 2 Airborne transmission through aerosols 3 can also contribute to the spread of the virus.…”