Investigation of SARS-CoV-2 E infection vaccination antibody levels among Clinical Microbiology Laboratory employees

COVID-19 is caused by the SARS-CoV-2 virus, which was declared a pandemic by the World Health Organization (WHO) on March 11, 2020. In our study, we aimed to determine SARS-CoV-2 infection, vaccination status and post-vaccination antibody levels in employees of Çukurova University Faculty of Medicine Hospital. 307 volunteer healthcare workers, 235 (76.5%) female, 72 (23.5%) male, with a mean age of 39.0 years (age range: 18.0-66.0 years), participated in the study. Serum samples were collected on 03.12.2021, 20.04.2022 and 28.09.2022. Anti-S-RBD IgG levels in serum samples were quantitatively determined with SNIBE Diagnostic MAGLUMI SARS-CoV-2 S-RBD IgG (CLIA) kit. 493 doses (47.54%) of Sınovac(CoronaVac) vaccine, 542 doses (52.26%) of Biontech vaccine and 2 doses (0.19%) of AstraZeneca vaccine were administered to 307 healthcare workers. Although anti-S-RBD-IgG Median Value (MD) was higher in women according to gender, it was not significant (p=0.096) and did not differ significantly according to chronic disease status (p=0.598). Anti-S-RBD-IgG distribution according to age groups was not significant (p=0.740). Anti-S-RBD IgG MDs according to vaccine dose were 104.5 AU/mL in those who received two doses of vaccine (24.4%), 111.6 AU/mL in those who received three doses of vaccine (29.3%), 107.8 AU/mL in those who received four doses of vaccine (29.6%), and 108.9 AU/mL in those who received 5 doses of vaccine (16.6%) and did not show a significant difference (p=0.103). Of the healthcare workers, 34.2% received homologous and 65.8% heterologous vaccination. It was observed that the anti-S-RBD-IgG MD of those with heterologous vaccination was higher than those with homologous vaccination (p<0.001). According to vaccination status, 12.7% were homologous-S (77.5 AU/mL), 21.8% were homologous-B (113.7 AU/mL), 19.5% were heterologous-SSB (120.8 AU/mL), 29.3% were heterologous-SSBB (107.9 AU/mL), 16.6% were heterologous-SSBBB (108.9 AU/mL). Anti-S-RBD IgG MD was found to be lower in the case of homologous-S (p<0.001). Anti-S-RBD-IgG MD was higher in those with a post-vaccination duration of ≤12 weeks (135.7 AU/mL) and 13-24 weeks (119.4 AU/mL) compared to those with 25-48 weeks (104.7 AU/mL) and 49+ weeks (97.8 AU/mL) (p<0.001). Among healthcare workers, 53.7% had never, 14.65% before vaccination, 41.0% once, and 5.2% twice had covid infection (PCR positive). No significant difference was found in the distribution of anti-S-RBD-IgG according to covid infection status (p=0.359). Among 307 healthcare workers, the rate of covid infection was 24.10% until 03.12.2021, 20.52% between 04.12.2021 and 20.04.2022, and decreased to 7.81% between 21.04.2022 and 28.09.2022. The most frequently reported side effects were; for Sinovac vaccine, vaccine arm-pain (12.98%), weakness (4.86%), headache (4.05%), fatigue (2.63%), back pain (2.02%); For Biontech vaccine, vaccine arm-pain (45.2%), vaccine site-pain (10.7%), fatigue (8.67%), weakness (15.12%), fever/shivering (11.07%), headache (8.67%), muscle pain (4.24%), joint pain (7.74%). In conclusion, those who received the Biontech vaccine reported more side effects than those who received the Sinovac vaccine. Serious side effects related to vaccines have been reported very rarely. Heterologous vaccination was associated with a higher antibody response than homologous vaccination. With homologous-B and heterologous SB vaccination, high anti-S-RBD-IgG levels above 100.00 AU/mL were observed up to 48 weeks. With vaccination, the high antibody levels achieved up to 12 weeks were significantly maintained up to 48 weeks.Healthcare workers who participated in the study contracted covid infections, but none had severe infections requiring hospitalization. Vaccination resulted in protective antibody levels against SARS-CoV-2 infection in healthcare workers.