Coronavirus Vaccination: Spike Antibody Levels in Health Workers after Six Months—A Cross-Sectional Study

Abstract

Healthcare workers bear a high risk of infection during epidemics and pandemics such as the current SARS-CoV-2 pandemic. Various new vaccines have been approved. We investigated the influence of the time elapsed since vaccination, as well as of vaccination schema, on health workers’ spike antibody levels following their second vaccination. Blood samples were obtained from employees working at a German hospital between August 2021 and December 2021 on average half a year (range 130–280 days) after their second vaccination. Levels of SARS-CoV-2-IgG antibodies (spike and nucleocapsid protein) were qualitatively detected via chemiluminescent immunoassays (CLIAs). A previous infection with SARS-CoV-2 was an exclusion criterion. In total, 545 persons were included in this cross-sectional study. Most participants (97.8%) showed elevated anti-spike concentrations. Anti-spike levels differed significantly among vaccination schemas. Repeated vector vaccinations resulted in lower protective antibody levels. Higher age levels, immunosuppression and a longer time period since the second vaccination resulted in lower anti-spike levels. Women’s antibody levels were higher, but not significantly. Since anti-spike levels drop after vaccination, further boosters are required to increase immunoreactivity. If two vector vaccines have been administered, it is possible that an mRNA booster might increase the anti-spike level.

Safety and Immunogenicity of Betuvax-CoV-2, an RBD-Fc-Based SARS-CoV-2 Recombinant Vaccine: Preliminary Results of the First-in-Human, Randomized, Double-Blind, Placebo-Controlled Phase I/II Clinical Trial

“…Another test, “SARS-CoV-2 IgG II Quant test system” (Abbott Laboratories, Chicago, Illinois, United States), for the detection of RBD-binding antibodies shows a good correlation between the sVNT values and is widely used for the assessment of immunity against SARS-CoV-2 [ 16 ]. For instance, the median level of the anti-RBD IgG antibodies up to 24 weeks after the prime-boost vaccination were around 600–2500 BAU/mL for mRNA-based vaccines, such as Comirnaty (Pfizer/Biontech, Mainz, Germany) and Spikevax (Moderna, Cambridge, MA, USA) [ 17 , 18 , 19 ]; for adenovirus-based vaccines as Vaxzevria (AstraZeneca/Oxford University) and Sputnik V (Gamaleya National Center of Epidemiology and Microbiology, Moscow, Russia)—around 200 BAU/mL [ 19 , 20 , 21 ]; for inactivated vaccine CoronaVac (Beijing, People’s Republic of China) this value was around 35 BAU/mL [ 22 ]. Therefore, compared to other common vaccines, the immunogenicity of the “Betuvax-CoV-2” at 20+20 μg dosing regimen, producing around 750 BAU/mL antibodies (measured by the Abbott test), is presumably on the similar level as with the mRNA-vaccines (Comirnaty, Spikevax) but has better RBD-based immunogenicity than inactivated (CoronaVac) and vector vaccines (Vaxzevria, Sputnik V).…”