Turkey's Manisa Celal Bayar University (MCBÜ) announced Wednesday findings from a study conducted on 1,053 healthcare professionals working at the university's Hafsa Sultan Hospital. The results revealed that those who received three doses of China's Sinovac COVID-19 vaccine achieved the level of protective antibodies.

According to the written statement from the university, MCBÜ's Scientific Research Projects Unit investigated the 6th-month follow-up results of the two-dose Sinovac SARS-CoV-2 inactivated vaccine – also known as CoronaVac – administered in Turkey and the efficacy results after a 3rd dose.

It stated that 1,053 health workers volunteered to participate in the study and the frequency of getting sick and the antibody levels created by the vaccine were investigated in the study group after the vaccination.

"In those with only two doses of CoronaVac, the levels of antibody protection decreased to 56% after the third month following the second vaccine. This data has proven that applying a 3rd dose of the vaccine is a sound decision," the statement read.

The study also showed a difference in efficacy between continuing with a third dose of CoronaVac or switching to BioNTech for the final dose, although both provided protection.

"Regardless of the preference of the third-dose vaccine, all individuals receiving three doses of vaccine achieved protective antibody levels. The BioNTech vaccine applied as the third dose of vaccination showed significant superiority in protection (both in terms of antibody levels and disease status) compared to the third dose of CoronaVac vaccine."

It also touched upon the subject of a further fourth booster shot.

"Those who received the third dose of BioNTech had antibody levels above the maximum measurable titer in 95% of the participants. As such, it can be considered that it is still early to apply the 4th dose of BioNTech vaccine after two doses of CoronaVac and one additional dose of BioNTech."

"The question of when the possible 2nd dose of BioNTech vaccine (4th dose in total) should be administered, can be answered when the results are obtained at the 3rd and 6th months after the 3rd dose administration."

The statement also noted: "None of the 44 employees who got sick in the period after the 3rd vaccine were hospitalized, and they had the disease on an outpatient basis."