Abstract
Before the end of December 2019, the epidemic was mainly localized in Wuhan, Hubei Province, China. Most of the cases in this stage were related to exposure to Huanan seafood market. "The virus is transmitted through human-to-human contact and rapidly spread across the world, and soon turned into a pandemic." Its symptoms can be divided to two main groups of majors (fever, cough, and dyspnea) and minors (anosmia, dysgeusia, headache, gastrointestinal symptoms, and skin lesions). Ever since, it has caused worldwide social and economic disruption, there are no universally recognized clinically useful antiviral drugs against COVID-19 so far (actually remdesivir showed good efficacy in many trials, but it needs to be further realized). Although there are several effective vaccines to prevent infection with SARS-CoV-2, efforts to develop medications and vaccines are continuing. Recently, a novel coronavirus, severe acute respiratory syndrome SARS-CoV-2, causing coronavirus disease 2019 (COVID-19), emerged in late 2019. During February 1-July 13, 2020, were identified 4,080 transmission pairs in Georgia, USA, by using contact tracing information from COVID-19 cases reported to the Georgia Department of Public Health. The novel coronavirus disease 2019 (COVID-19) outbreak and Italy has caused 6088 cases and 41 deaths in Republic of Korea and 3144 cases and 107 deaths in Italy by 5 March 2020. Currently, the following variants; Alpha, Beta, Gamma, Delta and Omicron were originated from United Kingdom, South Africa, Brazil/Japan, and India, respectively. The classification of SARS-CoV-2 variants is based on the mutations in the structure-based inclusions. Transmission varied not only by time and place but also by persons' sex and race. Younger adults (20–50 years of age) were involved in most transmission events.
Highlights
IntroductionIt is normal for viruses to change and evolve as they spread between people over time
During February 1-July 13, 2020, were identified 4,080 transmission pairs in Georgia, USA, by using contact tracing information from COVID-19 cases reported to the Georgia Department of Public Health
In another study performed in South Africa, when more than 90% of the total COVID-19 cases were due to the B.1.351 variant, the vaccine reached an efficacy of 60%
Summary
It is normal for viruses to change and evolve as they spread between people over time. Five mutations in the NTD of the S gene were proposed to contribute to improved viral microenvironment adaptations [30] This lineage is associated with increased spreading [19] and reinfection cases in subjects previously infected with the original SARS-CoV-2 [31]. In relation to omicron variant, there are some preliminary results from few studies with limited sample size suggesting that the incidence of virus reinfection in South Africa can be associated with humoral (antibody-mediated) immune evasion and nAb activity in vaccinated or previously infected individuals [40]. Convalescent sera have been used to evaluate the impact of variants on the nAb activity induced by the previous infection with the original SARS-CoV-2. A similar reduction in nAb activity was observed against the P.1 and B.1.1.7 variants (3.1 and 2.9-fold, respectively) [55]
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