Who needs a third dose?

Some recent speculations mentioned that a third dose of the vaccine might be recommended, and that we would have new vaccines for new variants of the virus.

Source: B92
EPA/Georgi Licovski
EPA/Georgi Licovski

As reported by some media, Gao Fu, head of the Chinese Center for Disease Control and Prevention, said that due to "low effectiveness" the combination of several types of vaccines against Covid 19 was being considered, causing panic among many citizens, although it was later explained that statement was misinterpreted.

"One type of clinical study examines whether one dose is effective and sufficient to protect us from infection. In the case of AstraZeneca, the first dose of the vaccine has been shown to be 70 to 75 percent effective, so it can protect us from disease for a period of time. The second dose is given only after 12 weeks as a booster dose, but again more for preventive reasons, and in that sense, the effectiveness is increased by another 20 percent. Then, we have variants like the Sputnik Light vaccine, which is given in one dose and protects us in the next 3 to 6 months after the infection and after that, it is necessary to receive another dose of the vaccine ", explained virologist Dr. Tanja Jovanovic for Television Prva.

"Another type of story is the story of the third vaccine and we have two directions. One is facing the emergence of new variants of the virus because the virus mutates and changes slowly those structures that are very important for neutralizing the virus with immunity caused after the vaccination. In this sense, the vaccine is less effective against new variants. Our country is dominated by the British variant and shown to be completely effective. South African and Brazilian variants are emerging. The second direction of the second story is whether to give a third dose of the same vaccine. or others to those who have not achieved effective immunity after vaccination."

Clinical studies have shown the effectiveness and Pfizer's about 95 percent, Sinopharm's between 80 and 85 percent and they differ in the way of inducing our protection against the virus.

"However, according to WHO recommendations and immunization goals, during pandemics it is important that the efficiency is at least 50 percent, and ours are much beyond that. Specifically, 95 percent effective means that if 100 people are vaccinated, 95 will be fully protected, and 10% of them will be able to become infected with the virus, but they will be protected from severe complications," emphasized Dr. Jovanovic.


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