A new study shows that the COVID-19 vaccines developed by Pfizer-BioNTech and Moderna-NIAID are very effective in preventing COVID-19 infection, both symptomatic and asymptomatic.
The study was published on March 29, 2021 in the journal Morbidity and Mortality Weekly Report, a publication from the United States Centers for Disease Control and Prevention (CDC).
From the study, researchers found that both vaccines can reduce the risk of infection by up to 80 percent after two weeks from the first injection. Meanwhile, the risk of COVID-19 infection fell by 90 percent within two weeks of receiving the second injection.
The study’s findings validate previous studies, which indicate that the vaccine starts working after the first dose, and ensures that the vaccine also prevents asymptomatic infections.
Because the research team cannot give a definitive answer what percentage of protection is provided if a person only gets one dose of injection, the CDC advises the public to stick with the recommended dose of the vaccine.
1. The importance of knowing the factor of vaccine effectiveness is not only from the efficacy of the vaccine
Vaccine effectiveness is the vaccine’s ability to reduce the incidence of disease in the real world, where the vaccine has been distributed to the public. It differs only from the efficacy which only shows the ability of the vaccine which is still in the research stage.
The level of effectiveness of the vaccine can be lower than the level of efficacy. This is due to several dynamic vaccine recipient factors. This of course cannot be separated from the different conditions of vaccine recipients and cannot be controlled one by one like during the study.
For example, we know that vaccines are not the only weapon against the virus that causes them COVID-19. Discipline in implementing health protocols remains to be done to prevent exposure to infections. However, what happens in the real world, even though the advice to adhere to health protocols continues to be echoed, in fact the decision to implement it or not depends on the people’s mindset.
That is what makes the effectiveness of the vaccine when tested in the real world is lower than the level of efficacy in clinical trials. Not because the strength of the vaccine has decreased, but the diversity of behavior of vaccine recipients must be considered if the results are like the level of efficacy during clinical trials.
2. Pfizer and Moderna vaccines can reduce COVID-19 infection, whether symptomatic or not
The study, which was conducted by the CDC, which was published on March 29, was conducted in the United States (US), involving 3,950 health workers and all those who work at the forefront of the health sector in six states.
It was reported that they received one of the vaccines between 14 December 2020 and 13 March 2021. In the study, no medical personnel had previously tested positive for COVID-19. About 74 percent have had at least one injection, and tests are performed every week on those infected with both symptoms and no symptoms.
As a result, 161 people infected with COVID-19 including unvaccinated medical personnel, 3 people infected after receiving two full doses of the vaccine, and 8 people infected with COVID-19 after receiving one dose of vaccine.
From the results of this study, experts concluded that the protection of Pfizer and Moderna vaccines was still classified as high and effective in reducing the risk of exposure to COVID-19, both with and without symptoms.
Also Read: What is AEFI COVID-19 Vaccine? This is the explanation!
3. Use of masks and physical distancing improve vaccine protection
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The effectiveness of vaccines in society can change quite a bit when researchers take into account factors such as gender, age, ethnicity and occupation of the vaccine recipient. However, due to the limited research on COVID-19 infection that occurred during the study period, research on the level of vaccine efficacy must be viewed with caution.
The results of vaccine efficacy studies from clinical trials to the community can vary widely, because there are factors that increase or decrease infection, such as a person’s behavior after being vaccinated.
One researcher said that the participants in the study were health workers and frontline workers. Thus, they are more likely to continue adhering to health protocols even after they have been vaccinated, so the results obtained during clinical trials can reach 90 percent efficacy.
