Are the COVID-19 vaccinations effective?

Wednesday, November 17, 2021

Will the COVID-19 vaccine protect me from COVID-19?

Yes. That’s right. When you get vaccinated against COVID-19, your body’s immune system learns how to fight the intrusion of the COVID-19 virus, protecting your body from getting sick with COVID-19.

Building immunity to the COVID-19 virus with vaccination is very important, as it can not only prevent infection with the COVID-19 virus, but also prevent severe infections or even death if you become infected with the COVID-19 virus.

What is the effectiveness of a vaccine?

The effectiveness of the vaccine is calculated as a percentage of how less likely the vaccinated group was to develop COVID-19 compared to the unvaccinated control group.

The proportionate reduction in attack rate between unvaccinated and vaccinated populations is the most commonly used measure of effectiveness. It can be calculated from the relative risk of disease in the vaccinated population.


What is the criteria for determining the effectiveness of the COVID-19 vaccine?

The World Health Organization (WHO)1 and the U.S. Food and Drug Administration (FDA)2 are setting criteria for a vaccine efficacy point estimate of at least 50% and a lower confidence interval greater than 30% for COVID-19 vaccination.

What were the results of the COVID-19 vaccine clinical trial?

  1. According to clinical trial data, the preventive effect of AstraZeneca COVID-19 vaccine was about 62%.
    • In two clinical trials in the UK (Phase 2 and 3) and Brazil (Phase 3), 8,895 people over the age of 18 who were negative for COVID-19 virus (4,440 in the vaccine group, 4,455 in the control group) were conducted (COVID-19 outbreak: 27 in the vaccine group) persons, control group 71 persons)
  2. According to clinical trial data, Pfizer’s COVID-19 vaccine was approximately 95% effective.
    • As a result of evaluation of 36,523 people aged 16 and older (18,198 in the vaccine group and 18,325 in the control group) who were negative for COVID-19 virus in a multinational clinical trial conducted in the United States, etc., those diagnosed with COVID-19 were 8 cases in the vaccine group and 162 cases in the control group
  3. According to the clinical trial data, in the case of the Janssen COVID-19 vaccine, 116 people in the vaccine group and 348 in the control group each occurred after 14 days of confirmed COVID-19, showing a preventive effect of 66.9%, and after 28 days, the vaccine 66 patients in the group and 193 patients in the control group showed a preventive effect of 66.1%.
    • Results of evaluation of 39,321 people 18 years of age or older (19,630 in the vaccine group and 19,691 in the control group) who were negative for COVID-19 in a multinational clinical trial conducted in the United States and other countries
  4. According to clinical trial data, the preventive effect of the Moderna COVID-19 vaccine was 94.1%.
    • As a result of clinical trials conducted in the United States, 11 patients (out of 14,134) in the vaccine group and 185 (out of 14,073) in the control group were each confirmed with COVID-19.

As the clinical trial results of Pfizer, Moderna, and AstraZeneca’s COVID-19 vaccines exceeded 50% of the vaccine efficacy standard suggested by the World Health Organization, it is expected to be effective in preventing infection and blocking the epidemic.

How long will the COVID-19 vaccine be effective?

Since COVID-19 vaccination is a vaccine developed after COVID-19 was discovered, it is not yet known how long the vaccine’s effectiveness will last.

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