Gareayaghi, NesrinDemirci, MehmetOzbey, DogukanDasdemir, FerhatDinc, Harika OykuBalkan, Ilker InancKocazeybek, BekirTıbbi Mikrobiyoloji / Medical MicrobiologyTıbbi Mikrobiyoloji / Medical Microbiology2024-05-252024-05-25202222076-393X10.3390/vaccines101016722-s2.0-85140873143https://doi.org/10.3390/vaccines10101672https://hdl.handle.net/20.500.14517/980Dinc, Harika Oyku/0000-0003-3628-7392; balkan, ilker inanc/0000-0002-8977-5931; Daşdemir, Ferhat Osman/0000-0003-3836-1680; Demirci, Mehmet/0000-0001-9670-2426; Kocazeybek, Bekir S/0000-0003-1072-3846This study aimed to determine the anti-S (receptor binding protein) RBD IgG antibody titers formed against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) and the neutralizing antibody inhibition percentages (nAb IH%) in blood samples taken after two doses of inactive or mRNA-based vaccine and a booster dose. Volunteers with two doses of inactivated CoronaVac (heterologous group; n = 75) and BioNTech (BNT)162b2 mRNA vaccine (homologous group; n = 75) were included in this study. All participants preferred the BNT162b2 vaccine as a booster dose. First, peripheral blood samples were taken 3 months after the second vaccine dose. Second, peripheral blood samples were taken 1 month after the booster dose. Anti-S-RBD IgG titers were determined by CMIA (SARS-CoV-2 IgG II Quant). Neutralizing antibodies were detected by a surrogate neutralization assay (SARS-CoV-2 NeutraLISA, Euroimmun, Lubeck, Germany). The median age of the volunteers was 40 (IQR 29-47) years old. After the heterologous booster dose, anti-S-RBD IgG levels and neutralizing antibodies increased approximately 50-fold and 9-fold, respectively. Anti-S-RBD IgG titers increased by 9 and 57 times, respectively, while nAb IH% increased by 1.5 and 16 times, respectively, among those with heterologous reminder doses and those with and without a prior history of coronavirus disease (COVID-19). This study showed that after the administration of a heterologous booster dose with BNT162b2 to those whose primary vaccination was with inactivated CoronaVac, the binding and neutralizing antibody levels were similar to those who received a homologous BNT162b2 booster dose. It was observed that the administration of heterologous and homologous booster doses resulted in the development of similar levels of neutralizing antibodies, independently from a prior history of COVID-19.eninfo:eu-repo/semantics/openAccessCoronaVacBNT162b2neutralizing antibodybinding antibodyArticleQ1Q21010WOS:00087358470000136298537