Although the vaccination program in Turkey against the coronavirus pandemic gained momentum over the summer, concerns remain on the period of efficacy of vaccines. The country started administering third doses of inactive CoronaVac vaccine and now plans to administer third or booster shots for the Pfizer-BioNTech jab, the second vaccine available in Turkey.

A report published by the Hürriyet newspaper on Tuesday says the Health Ministry's Coronavirus Scientific Advisory Group discussed the matter and the ministry would soon announce the eligibility rules for third doses. The booster shots aim to revive the impact of the vaccine on immunity and studies suggest that two doses of vaccine lose their efficiency within six months after the second dose.

Israel was the first country to offer the third dose of the Pfizer-BioNTech Messenger RNA (mRNA) vaccine while the Food and Drugs Administration (FDA) in the United States approved the third dose for the elderly and people under risk. The report says Turkey will decide on third doses after the results of a nationwide study that examines the antibody levels. The study will also serve as a guide for a decision on whether people who have had two doses of CoronaVac and a third dose of Pfizer-BioNTech vaccine will require a fourth shot.

On Monday, The European Medicines Agency (EMA) had recommended a booster shot for the vaccine for people with severely weakened immune systems 28 days after the second dose. The EMA had concluded that the data showed "a rise in antibody levels when a booster dose is given approximately six months after the second dose in people from 18 to 55 years old." It did not directly advise a third dose for healthy adults. Pfizer-BioNTech vaccines were the first COVID-19 jabs authorized in the European Union, and the bloc financially contributed to the development of the vaccine under an advanced purchase agreement signed in 2020.

The vaccine is based on a messenger molecule with instructions to produce a protein from the virus that causes COVID-19 to prepare the body to fight the disease. Unlike most other vaccines, it does not contain the virus itself.

Health Minister Fahrettin Koca had earlier announced that 31 million vaccinated people were examined in a study that found three doses lowered the risk of infection compared to two doses and prevented hospitalizations and intensive care stays for the infected. The minister has also said that the preliminary results of the study showed that the efficacy of two doses of the Pfizer-BioNTech vaccine may decrease with time. Professor Mustafa Hasöksüz, a member of the Coronavirus Scientific Advisory Board, told Hürriyet that there was no comprehensive study to confirm vaccine developers’ claims that the vaccine protects against the virus for eight to 12 months.

BioNTech co-founder Özlem Türeci told CNBC last week that booster doses appeared protective on their own for every variant in existence but she warned that her company has to keep observing the new variants and the Pfizer-BioNTech vaccine may not protect against some future strains. The scientist also said that booster doses may be administered every 12 or 18 months in the future, adding that they need more research data to help determine a way out of the COVID-19 pandemic entirely.

One of the biggest concerns surrounding the Pfizer-BioNTech vaccine and its safety is that it was developed within a year; however, the company has already been working on the mRNA technology for years. The company has launched research on "pioneering individualized immunotherapies" for cancer medicine using its mRNA technology, which stimulates the body’s own immune response.

"So we had, already, the science and the knowledge about immune mechanisms and how they can be used against viruses and could leverage that," Türeci said. "And the other pillar of our response was our technology, the mRNA technology, which allows (it) to be used as a vaccine format, which means it allows (it) to communicate with the immune system and teach it how to respond against this new enemy with high precision," she added. Türeci noted that this technology was "already ripe," as they had used it during clinical trials for cancer.