[Efficacy of Homologous and Heterologous Vaccine Applications on SARS-CoV-2 Omicron Variant: Cohort of Manisa Celal Bayar University Healthcare Workers]. / Homolog ve Heterolog Asi Uygulamalarinin SARS-CoV-2 Omicron Varyanti Üzerindeki Etkililigi: Manisa Celal Bayar Üniversitesi Saglik Çalisanlari Kohordu.

This study was aimed to determine the efficacy of homologous (only CoronaVac or only Pfizer-BioNTech) and heterologous (CoronaVac and Pfizer-BioNTech) vaccines during the period when the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Omicron variant was dominant in Türkiye. Coronavirus disease-2019 (COVID-2019) infection was confirmed by reverse transcriptase polymerase chain reaction and data on vaccination status against COVID-19 were evaluated during the period of 15 January 2022-1 May 2022 when the SARS-CoV-2 Omicron variant was dominant among 1854 employees followed in the SARS-CoV-2 Vaccine Cohort of Manisa Celal Bayar University (MCBU) Hospital Health Workers. Two separate reference groups were used in the evaluation of vaccine efficacy: those who were never vaccinated and those who received only two doses of CoronaVac. The efficacy of homologous and heterologous vaccine models was evaluated with relative risks and attributable risk percentages. MS Excel, SPSS 23.0 and STATA 14.1 package programs were used for statistical analysis. The mean age of the participants was 36.6 ± 10.0. During the period from January 15th to May 1st 2022, 372 hospital workers were infected with COVID-19. Taking the never vaccinated as the reference group, the most effective model was found to be only the three or more doses of the Pfizer-BioNTech primary vaccination model (85.8%, 95% CI= 40.7-96.6). Models consisting of a single dose of CoronaVac (6.5%, 95% CI= -56.3-44.2) or a single dose of Pfizer-BioNTech (17.7%, 95% CI= -30.2-48.0) booster dose administered after two doses of primary CoronaVac vaccination was not found to be effective against the SARS-CoV-2 Omicron variant. When only two doses of primary CoronaVac vaccination model was taken as the reference group, the model consisting of two doses CoronaVac followed by two Pfizer-BioNTech booster doses was effective as 38.4% (95% CI= 15.4-55.3), whereas three doses of Pfizer-BioNTech booster model was effective as 56.4% (95% CI= 33.9-71.3). To conclude, none of the models other than the homologous or heterologous vaccine models containing at least three doses of Pfizer-BioNTech vaccine were effective compared to those unvaccinated. Compared with those who received only two doses of primary Coronavac, models with at least three doses of Pfizer-BioNTech reminder doses were more effective against the Omicron variant than other models.

[Antibody Sustainability in SARS-CoV-2 Healthcare Professionals' Patient Cohort]. / Saglik Çalisanlari SARS-CoV-2 Hasta Kohordunda Antikor Sürdürülebilirligi.

In this study, it was aimed to evaluate one-year follow-up of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) specific antibodies formed against the virus binding site, in a coronavirus disease-2019 (COVID-19) positive case cohort (n= 413) between the period March 2020 to December 2020 in Manisa Celal Bayar University Hospital, until July 2021. SARS-CoV-2 antibodies were determined by the chemiluminescent enzyme immunoassay (CLIA) method. Values of 1.0 and above were considered positive. Chi-square tests and Joinpoint regression analysis (version 4.7.0) were used in the statistical analyses. The mean age of the participants was 34.9 ± 9.3 and 60.2% of them were women. Between 21-30 days after the diagnosis of COVID-19, total antibody level was above the threshold value in 72.2% (n= 126) of the participants, while this rate increased to 79.1% (n= 240) in 31-60 day interval. In the following period, this rate decreased to 38.8% (n= 108) in days 211st to 240th. Antibody response could not be detected in 76 (20.7%) of 367 employees who have initially been followed up. The percentage of total antibody positivity prevalence ranged from 98.9% to 96.1% in the 31-210th day after diagnosis, in the follow-up of 291 employees whose total antibody positivity was detected after diagnosis. According to the results of the Joinpoint regression analysis, after the diagnosis of COVID-19, the curve showing the percentage of antibody positivity was broken at two points: The first breaking point was observed in 181-210th days (6-7 months) (p= 0.069), and the second breaking point was in 271-300th days (9-10 months) (p< 0.001). As a result, the highest antibody positivity rates were detected after the 30th day of the disease onset and antibody positivity was maintained in the first seven months after diagnosis; the antibody positivity rate decreased to 25% at the end of the first year.