COVID-19 Vaccine

                            COVID-19 Vaccine

A COVID‑19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), the virus causing coronavirus disease 2019 (COVID‑19). Prior to the COVID‑19 pandemic, there was an established body of knowledge about the structure and function of coronaviruses causing diseases like severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), which enabled accelerated development of various vaccine technologies during early 2020.[1] On 10 January 2020, the SARS-CoV-2 genetic sequence data was shared through GISAID, and by 19 March, the global pharmaceutical industry announced a major commitment to address COVID-19. 

In Phase III trials, several COVID‑19 vaccines have demonstrated efficacy as high as 95% in preventing symptomatic COVID‑19 infections. As of April 2021, 13 vaccines are authorized by at least one national regulatory authority for public use: two RNA vaccines (Pfizer–BioNTech and Moderna), five conventional inactivated vaccines (BBIBP-CorV, CoronaVac, Covaxin, WIBP-CorV and CoviVac), four viral vector vaccines (Sputnik V, Oxford–AstraZeneca, Convidecia, and Johnson & Johnson), and two protein subunit vaccines (EpiVacCorona and RBD-Dimer).[3][failed verification] In total, as of March 2021, 308 vaccine candidates are in various stages of development, with 73 in clinical research, including 24 in Phase I trials, 33 in Phase I–II trials, and 16 in Phase III development.

Effectiveness

The real-world studies of vaccine effectiveness measure to which extent a certain vaccine has succeeded in preventing COVID-19 infection, symptoms, hospitalization and death for the vaccinated individuals in a large population under routine conditions that are less than ideal.

• In Israel, among the 715,425 individuals vaccinated by the Moderna or Pfizer-BioNTech vaccines during the period 20 December 2020, to 28 January 2021, it was observed for the period starting seven days after the second shot, that only 317 people (0.04%) became sick with mild/moderate Covid-19 symptoms and only 16 people (0.002%) were hospitalized.

• The Pfizer-BioNTech and Moderna Covid-19 vaccines provide highly effective protection, according to a report from the US Centers for Disease Control and Prevention. Under real-world conditions, mRNA vaccine effectiveness of full immunization (≥14 days after second dose) was 90% against SARS-CoV-2 infections regardless of symptom status; vaccine effectiveness of partial immunization (≥14 days after first dose but before second dose) was 80%.