According to a new study, the third dose of AstraZeneca, Pfizer-BioNTech or Johnson & Johnson vaccine against Covid-19, administered on top of two doses of Sinovac vaccine, significantly increases the level of antibodies in the body.
The study carried out by Oxford University together with Brazilian researchers revealed that the CoronaVac vaccine produced by the Beijing-based Sinovac pharmaceutical company with the inactive virus method, which is an old technique, has become more effective by being supported by new types of vaccines produced with mRNA or viral vector technique.
According to research funded by the Brazilian Ministry of Health, a third dose of a different vaccine administered on top of two doses of Sinovac vaccine increases the level of antibodies in the body and increases resistance to Delta and Omicron variants.
The Sinovac vaccine, which is applied in about 50 countries around the world, including Turkey, Brazil, China, Argentina and South Africa, aims to make the body immune to the disease by injecting the dead or inactive virus that has lost its infecting feature.
Vaccines produced with the mRNA technique, such as Moderna and BioNTech, create immunity by partially injecting the genetic code of the coronavirus into the body, which is produced in the laboratory.
In viral vector vaccines such as Sputnik V and Oxford/Astrazeneca, some of the genetic material carried by the virus is transferred to the body by placing it in another virus, again using gene technology.
New options for countries using CoronaVac
Oxford University Vaccine Group President Prof. Andrew Pollard said, “This research shows that the inactive CoronaVac vaccine can make the body more resistant to Covid-19 by being supplemented with third-dose vaccines, primarily produced with viral vector or mRNA technologies.”
Turkish Minister of Health Fahrettin Koca said that 90 percent of the people who were hospitalized due to Covid-19 in the past months were not fully vaccinated.
On the other hand, specialist physicians stated that those treated in intensive care units were either unvaccinated or did not receive the third dose of vaccine on top of the double dose of Sinovac vaccine.
Pollard said, “The priority is to make first and second vaccines in the world, but the findings of this study will offer new options for countries where inactivated vaccines such as CoronaVac are used.”
Another study, conducted in December by Yale University and the Dominican Republic Ministry of Health, but not yet peer-reviewed, suggested that the Pfizer-BioNTech vaccine administered after two doses of Sinovac vaccine lowered immunity against the Omicron variant.