ISTANBUL -- A Turkish study of more than 30 million vaccinated citizens indicated that the highest level of protection was seen in people who received three doses of inactive vaccines, rather than in those who received two doses of inactive vaccines and one booster shot of an mRNA vaccine, the country's Health Minister Fahrettin Koca said on Wednesday.
While the minister avoided specifying brand names, he was referring to the vaccines now available in Turkey: the Chinese inactive vaccine CoronaVac by Sinovac Biotech and the mRNA offering developed by Pfizer and BioNTech.
While many Turks have preferred receiving a Pfizer booster shot, believing it is more effective than the Chinese vaccine, the research shows that using the same vaccine type works better. Health authorities in Turkey and other countries had been recommending that people inoculated with two doses of inactive vaccines receive an mRNA jab as a third dose to boost protection.
"Having three doses in designated groups is very important," Koca said. "People around the world will learn this data for the first time, and countries' vaccination policies will perhaps change."
He added that the researchers who carried out the study on Wednesday applied to a scientific journal to publish the full results.
Turkey has obtained tens of millions of doses of Sinovac since the beginning of the year and has administered it widely, starting with older adults. The Pfizer shots started to arrive in March, with the country accelerating procurement from June. Many in Turkey have sought out the Pfizer dose as the booster shot.
Turkey has also received a small quantity of Russian Sputnik V.