Stating that COVID-19 vaccines have been proven to be safe, effective and life-saving, WHO states that, as with all vaccines, vaccination does not provide complete (100%) protection, but also states the importance of vaccination for the course of the epidemic. In addition, although it is not known to what extent vaccines can prevent people from transmitting the virus to others, it is accepted that they certainly reduce transmission to a considerable extent. Therefore, in addition to being vaccinated, it is recommended to continue to take other measures to combat the epidemic.
How is the effectiveness of vaccines determined?
All COVID-19 vaccines approved by WHO for the emergency use list have undergone randomized clinical trials to test their quality, safety, and efficacy. In order for vaccines to be approved, the efficacy rate must be 50% or more. After this approval, it continues to be monitored for continued safety and effectiveness. The efficacy of a vaccine is determined in a controlled clinical trial and is based on how many people vaccinated develop the “same outcome” (usually disease) compared to how many people who receive a placebo develop the same outcome.
After the study is completed, the number of sick people in each group is compared to calculate the relative risk of getting sick based on whether the subjects received the vaccine. Thus, the effectiveness of the vaccine is obtained. In other words, a measure of how much the vaccine reduces the risk of getting sick. If a vaccine is highly effective, far fewer people in the group receiving the vaccine would be expected to get sick than the group given the placebo. For example, let’s consider an 80% proven efficacy vaccine. This means that people in the clinical trial who received the vaccine had an 80% lower risk of developing the disease than the group who received the placebo. Therefore, it is calculated by comparing the number of sick cases in the vaccinated group with the placebo group. The 80% effectiveness of the vaccine does not mean that 20% of the vaccinated group will get sick.
In double-dose vaccines, the first dose provides partial protection.
Vaccines can provide strong protection, but this protection requires a certain period of time. First of all, all necessary vaccine doses must be administered to establish full immunity. For two-dose vaccines, the vaccines provide only partial protection after the first dose and the second dose increases this protection. For a single-dose vaccine, maximum immunity against COVID-19 is expected a few weeks after vaccination.
Pay attention to precautions against COVID-19 after vaccination!
Vaccines can prevent most individuals from contracting COVID-19, but not everyone. You can become infected even after taking all recommended doses and waiting several weeks for immunity to develop. Vaccines do not provide full (100%) protection, so it is important to pay attention to preventive measures against the epidemic. After the vaccination, it is necessary to continue to take simple measures such as social distance, wearing a mask, good ventilation of the rooms, avoiding crowds, and hand cleaning. Although vaccinated individuals are infected with COVID-19, they are expected to have the disease with milder symptoms. In general, the probability that someone who is vaccinated will have a serious illness or die is very low.
It can prevent hospitalization and the serious course of the disease!
As cases increase and transmission accelerates, new dangerous and more contagious variants are more likely to emerge that can spread more easily or cause more serious illness. Based on the information available so far, it can be said that vaccines are effective against existing variants, especially in the prevention of severe course of the disease, hospitalization and deaths due to COVID-19. Vaccines remain effective against variants due to the broad immune response they cause, meaning that virus changes or mutations are unlikely to render vaccines completely ineffective. WHO also emphasizes that one of the best ways to protect against new variants is to continue to implement public health measures and to be vaccinated.