ABSTRACT
Variants of concern (VOCs) like Delta and Omicron, harbor a high number of mutations, which aid these viruses in escaping a majority of known SARS-CoV-2 neutralizing antibodies (NAbs). In this study, Rhesus macaques immunized with 2-dose inactivated vaccines (Coronavac) were boosted with an additional dose of homologous vaccine or an RBD-subunit vaccine, or a bivalent inactivated vaccine (Beta and Delta) to determine the effectiveness of sequential immunization. The booster vaccination significantly enhanced the duration and levels of neutralizing antibody titers against wild-type, Beta, Delta, and Omicron. Animals administered with an indicated booster dose and subsequently challenged with Delta or Omicron variants showed markedly reduced viral loads and improved histopathological profiles compared to control animals, indicating that sequential immunization could protect primates against Omicron. These results suggest that sequential immunization of inactivated vaccines or polyvalent vaccines could be a potentially effective countermeasure against newly emerging variants.
Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , Macaca mulatta , SARS-CoV-2/genetics , Vaccination , Vaccines, Inactivated/geneticsSubject(s)
COVID-19 Vaccines/supply & distribution , COVID-19/prevention & control , Adenoviridae/genetics , Adult , COVID-19/epidemiology , COVID-19/immunology , COVID-19 Vaccines/economics , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , Coronavirus Nucleocapsid Proteins/genetics , Coronavirus Nucleocapsid Proteins/immunology , Drug Approval , Economic Factors , Humans , Iran/epidemiology , Measles virus/genetics , Phosphoproteins/genetics , Phosphoproteins/immunology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vaccines, Inactivated/genetics , Vaccines, Inactivated/immunology , Vaccines, Inactivated/supply & distribution , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunology , Vaccines, Synthetic/supply & distributionABSTRACT
Today the coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has become a global health problem. After more than a year with the pandemic, although our knowledge has progressed on COVID-19, there are still many unknowns in virological, pathophysiological and immunological aspects. It is obvious that the most efficient solution to end this pandemic are safe and efficient vaccines. This manuscript summarizes the pathophysiological and thrombotic features of COVID-19 and the safety and efficacy of currently approved COVID-19 vaccines with an aim to clarify the recent concerns of thromboembolic events after COVID-19 vaccination. The influx of newer information is rapid, requiring periodic updates and objective assessment of the data on the pathogenesis of COVID-19 variants and the safety and efficacy of currently available vaccines.
Subject(s)
COVID-19 Vaccines/adverse effects , COVID-19/prevention & control , SARS-CoV-2 , Thrombosis/etiology , Ad26COVS1 , Autoantibodies/biosynthesis , BNT162 Vaccine , COVID-19/epidemiology , COVID-19/physiopathology , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , ChAdOx1 nCoV-19 , Clinical Trials as Topic , Disseminated Intravascular Coagulation/epidemiology , Disseminated Intravascular Coagulation/etiology , Drug Approval , Female , Genetic Vectors , Glycosaminoglycans/immunology , Humans , Male , Models, Cardiovascular , Pandemics/prevention & control , Platelet Factor 4/immunology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Safety , Sinus Thrombosis, Intracranial/epidemiology , Sinus Thrombosis, Intracranial/etiology , Thrombosis/epidemiology , Thrombosis/physiopathology , Vaccines, Inactivated/adverse effects , Vaccines, Inactivated/genetics , Vaccines, Inactivated/immunology , Vaccines, Synthetic/adverse effects , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunologyABSTRACT
SARS-CoV-2 has been detected in more than 141 million people and caused more than 3 million deaths worldwide. To reduce the additional loss of millions of lives until natural immunity is reached, researchers have focused on the only known method to stop the COVID-19 pandemic: vaccines. The pandemic has propelled high-speed vaccine development, some based on novel technology previously not utilized in the vaccine field. The new technology opens new possibilities and comes with challenges because the long-term performance of the new platforms is unknown. Here we review the current leading vaccine candidates against COVID-19 and outline the advantages and disadvantages as well as the unknowns of each candidate.