The Health Ministry started administering third or booster doses six months after the beginning of its inoculation campaign against the coronavirus. Medical experts say the country needs to bolster its mass immunity and third doses are necessary to stave off a possible fourth wave in the pandemic.

The delta variant, more infectious when compared to the alpha variant, is the main source of concern for most countries and although Turkey has fewer variant cases than others, the strain still poses a risk. Professor Ismail Balık, an infectious diseases expert, says the variant is "60% more infectious" than alpha and affects children and youth more, unlike the earlier strain of the coronavirus. "It spreads faster among those not vaccinated. It is true that it reduces efficacy of vaccines but it is less effective on people who have had both their doses," he said.

Third doses are currently being administered to health care workers and people aged 50 and above as these groups were the first to get vaccinated when the campaign started in January 2021. Those eligible can choose a different vaccine for the third shot. Professor Tuba Dal of Ankara Yıldırım Beyazıt University’s faculty of medicine, says the third dose will help in "boosting" antibody levels which are depleted even after second dose. "Basically, they ‘remind’ the body of the presence of virus," she says.

Professor Sema Turan, member of Health Ministry’s Coronavirus Scientific Advisory Board which recommended to the government administering a third dose, says both inactive and messenger RNA (mRNA) vaccines – offered to the Turkish public currently – aim to create an antibody response in the body against the coronavirus but with time, this response decreases. "In most cases, antibody levels decrease within six months and this in turn, aggravates risk of infection," she said.

Professor Kenan Midilli, another member of the Board, said both groups eligible for third doses are under "higher risk" and their vaccination would help in achieving a stronger immunity against the delta variant. Professor Necmettin Ünal, a medical expert from Ankara University, says the Pfizer-BioNTech vaccine had offered "33% protection" with one dose, against the delta variant, and with two doses, this rate rises to 88%. Ünal said Sinovac’s vaccine appears less protective against the delta but a third dose can provide sufficient protection. He pointed out that Turkey needs 70% of its population vaccinated with at least two doses of vaccines to achieve mass immunity to end the pandemic.

Following an increase in vaccination rates, the country recorded a significant decline in daily cases, from as high as 60,000 in April to around 5,000 nowadays. In light of the decrease, the government has decided to lift most restrictions, including daily curfews and weekend lockdowns. After suffering a slowdown in vaccination figures due to unexpected delays in shipments of doses, Turkey has significantly increased the reach and the speed of the campaign.