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Impact of COVID-19 Vaccines on Disease Evolution

USA Experience
(Centers for Disease Control & Prevention (CDC)

November 16, 2022

  • ​The following information is based on a review of data for 30 health sectors covering 70% of the population in the United States of America.
  • Despite the emergence of many mutants of the virus that causes Covid-19 disease, studies have shown that approved vaccines, the most important of which are mRNA-based, are still effective in reducing rates of hospitalization and death due to the disease.
  • Unvaccinated people, of all age groups, are at greater risk of severe complications and death than people who have received at least the basic COVID-19 vaccine.
  • The risk of dying from COVID-19 in the unvaccinated compared to those who received basic vaccinations:
    • ​4 times higher in the age group 80 years and over.
    • 9 times higher in the 65-75 age group.
    • 6 times higher in the 50-64 age group.
    • 5 times higher in the 30-49 age group.
    • 3 times higher in the 18-29 age group.
  • ​Age group of 50 years and over who received two booster doses had a 3 times lower risk of death compared to those who received one booster dose of the same age group.
  • Deaths of those who received the vaccine were those with chronic diseases and immunodeficiencies.
  • COVID-19 patients who received two or three vaccines have a 90% lower risk of severe disease complications, including the need for artificial respiration in intensive care, regardless of age.
  • At the beginning of the emergence of the Omicron mutant, those who received two doses of the vaccine decreased their risk of entering intensive care and undergoing artificial respiration by 79%. While the risk decreased by 94% for those who received 3 doses.
  • *A study measuring the effectiveness of vaccination: among the age group of 50 years and over, the effectiveness of vaccination with three doses (2 basic and 1 booster) after 120 days amounted to 32%, while the percentage increased to 66% for those who received the second booster dose after approximately 28 days.

*Link-Gelles R, Levy ME, Gaglani M, Irving SA, Stockwell M, Dascomb K, et al. Effectiveness of 2, 3, and 4 COVID-19 mRNA Vaccine Doses Among Immunocompetent Adults During Periods when SARS-CoV-2 Omicron BA.1 and BA.2/BA.2.12.1 Sublineages Predominated – VISION Network, 10 States, December 2021 -June 2022. MMWR Mortal Mortal Wkly Rep 2022;71(29):931-939. ​

Last Update : 20 January 2023 03:12 AM
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