SARS-CoV-2 antibody response after mRNA vaccination in healthcare workers with and without previous COVID-19, a follow-up study from the University Hospital in Krakow, Poland

Abstract

IntroductionHealthcare workers (HCWs) from the beginning of the pandemic have been at risk of exposure to SARS-CoV-2, so they were vaccinated as first.ObjectivesThe purpose of the study was to determine the level of antibodies against SARS-CoV-2 in HCWs before and after vaccination with mRNA preparations according to previous COVID- 19.Patients and methodsThe HCWs from the University Hospital in Krakow completed two surveys: the baseline survey before receiving the first dose of vaccine (in January 2021) and the follow-up survey in June 2021. In parallel, two blood samples were collected from each participant at baseline and at follow-up. Total anti-SARS-CoV-2 antibody levels were measured using the ECLIA technique.ResultsAt baseline, 41.1% of HCWs had positive antibody test results, and at follow-up, the vaccinated HCWs had almost 100 times higher antibody levels than the unvaccinated HCWs. Participants under 30 years of age had significantly higher antibody levels in June than older HCWs. Among participants with positive antibody test results in January, HCWs who had experienced asymptomatic COVID-19 had more than five times higher antibody levels in June than HCWs self-reported severe COVID-19. In total, 86.9% of HCWs received Comirnaty or Spikevax. The incidence rate of COVID-19 in the unvaccinated vs. vaccinated group was 13 times higher, 20.5% and 1.9% respectively.ConclusionsThese results confirm the effectiveness of vaccination in the prevention of COVID-19 in HCWs. It is worth getting vaccinated regardless of previous infection. Furthermore, vaccination among HCWs under 30 years of age induced more effective antibody production compared to older individuals.

Analysis of COVID-19 Incidence and Protective Potential of Persisting IgG Class Antibodies against SARS-CoV-2 Infection in Hospital Staff in Poland

“…In our study group, IgG class anti-SARS-CoV-2 antibody levels were significantly lower among people who had previously had COVID-19 than among those who received COVID-19 vaccination, which is consistent with the reports of other researchers [50]. This confirms the high immunogenicity of vaccines against COVID-19 reported in the Polish population in other studies [51] for the immune response evoked by the vaccine and the magnitude of the response sustained over time [52].…”

Immune Response to COVID-19 Vaccination in Frontline Healthcare Workers

“…Healthcare workers are definitely a priority group for vaccination against COVID-19 [ 8 ]. Therefore, healthcare workers were vaccinated first, in order to protect the vulnerable part of the population and frontline employees and to stop the spread of the virus and the spread of COVID-19.…”

“…Therefore, nowadays, when COVID-19 has become a constant companion in our daily lives, vaccination is an irreplaceable means of preventing this epidemic [ 7 ]. Studies revealed the effectiveness of vaccination against COVID-19 and also after getting infected with SARS-CoV-2 in healthcare employees [ 8 ].…”

“…Long-term effects of vaccines on antibody levels showed that the decrease in antibody titer was significantly associated with the male sex, older age, and time after vaccination [ 11 ]. Vaccination in young people induces more effective, faster, and longer antibody production compared with older people [ 8 , 16 ]. A lower number of lymphocytes in the blood and a higher body mass index lead to a lower immune response.…”

Incidence of SARS-CoV-2 infection among healthcare workers before and after COVID-19 vaccination in a tertiary paediatric hospital in Warsaw: A retrospective cohort study

“…There is limited data on the incidence of SARS-CoV-2 infection among HCWs beyond the second wave of the pandemic, and limited data on the incidence of infection before and after the implementation of the vaccination programme, especially for European countries [ 10 ]. So far, most studies performed in Poland were voluntary seroprevalence studies, so the representativeness of the results obtained may be limited [ 11 , 12 ]. Knowing the factors associated with SARS-CoV-2 infection in HCWs informs preventive measures and improves the protection of HCWs and patients.…”