The Impact of SARS-CoV-2 Variants on Morbidity, Mortality and Effectiveness of Vaccines

Coronaviruses are known to evolve slower than the other RNA viruses; however, SARS-CoV-2 underwent a major shift through D614G change in February 2020, even before the declaration of a pandemic by WHO and D614G variant became rapidly dominant throughout the world. The spike protein of this variant with D614G change have a higher affinity to human ACE-2 and gained a transmission advantage against other circulating variants. Some mutations may confer advantages for the virus, and the variants carrying this kind of mutations may outcompete the previous variants (1). A mutation may cause changes in biology, transmissibility, susceptibility of the virus against naturally or vaccine-induced immunity, and the presentation and outcome of the disease caused by the virus. All of these changes may pose extra challenges regarding the containment of the epidemic, treatment and prevention of the disease using antivirals, immunotherapeutics like monoclonal antibodies or convalescent plasma, and vaccines (2,3).