Skip to main navigation menu Skip to main content Skip to site footer
##common.pageHeaderLogo.altText##

Original article

Vol. 154 No. 4 (2024)

SARS-CoV-2 immunity and reasons for non-vaccination among healthcare workers from eastern and northern Switzerland: results from a nested multicentre cross-sectional study

  • Selina Albrecht
  • Fabian Grässli
  • Alexia Cusini
  • Angela Brucher
  • Stephan Goppel
  • Elsbeth Betschon
  • J. Carsten Möller
  • Manuela Ortner
  • Markus Ruetti
  • Reto Stocker
  • Danielle Vuichard-Gysin
  • Ulrike Besold
  • Lorenz Risch
  • Matthias von Kietzell
  • Matthias Schlegel
  • Pietro Vernazza
  • Stefan P. Kuster
  • Christian R. Kahlert
  • Philipp Kohler
DOI
https://doi.org/10.57187/s.3734
Cite this as:
Swiss Med Wkly. 2024;154:3734
Published
13.04.2024

Summary

AIMS OF THE STUDY: We aimed to assess the extent of SARS-CoV-2 humoral immunity elicited by previous infections and/or vaccination among healthcare workers, and to identify reasons why healthcare workers decided against vaccination.

METHODS: This nested cross-sectional study included volunteer healthcare workers from 14 healthcare institutions in German-speaking Switzerland. In January 2021, SARS-CoV-2 vaccines were available for healthcare workers. In May and June 2022, participants answered electronic questionnaires regarding baseline characteristics including SARS-CoV-2 vaccination status (with one or more vaccine doses defined as vaccinated) and previous SARS-CoV-2 infections. Unvaccinated participants indicated their reasons for non-vaccination. Participants underwent testing for SARS-CoV-2 anti-spike (anti-S) and anti-nucleocapsid (anti-N) antibodies. Antibody prevalence was described across age groups. In addition, we performed multivariable logistic regression to identify baseline characteristics independently associated with non-vaccination and described reasons for non-vaccination.

RESULTS: Among 22,438 eligible employees, 3,436 (15%) participated; the median age was 43.7 years (range 16–73), 2,794 (81.3%) were female, and 1,407 (47.7%) identified as nurses; 3,414 (99.4%) underwent serology testing, among whom 3,383 (99.0%) had detectable anti-S (3,357, 98.3%) antibodies, anti-N (2,396, 70.1%) antibodies, or both (2,370, 69.4%). A total of 296 (8.6%) healthcare workers were unvaccinated, whereas 3,140 (91.4%) were vaccinated. In multivariable analysis, age (adjusted OR [aOR] 1.02 per year, 95% CI 1.01–1.03), being a physician (aOR 3.22, 95% CI 1.75–5.92) or administrator (aOR 1.88, 95% CI 1.27–2.80), and having higher education (aOR 2.23, 95% CI 1.09–4.57) were positively associated with vaccine uptake, whereas working in non-acute care (aOR 0.58, 95% CI 0.34–0.97), active smoking (aOR 0.68, 95% CI 0.51–0.91), and taking prophylactic home remedies against SARS-CoV-2 (aOR 0.42, 95% CI 0.31–0.56) were negatively associated. Important reasons for non-vaccination were a belief that the vaccine might not have long-lasting immunity (267/291, 92.1%) and a preference for gaining naturally acquired instead of vaccine-induced immunity (241/289, 83.4%).

CONCLUSIONS: Almost all healthcare workers in our cohort had specific antibodies against SARS-CoV-2 from natural infection and/or from vaccination. Young healthcare workers and those working in non-acute settings were less likely to be vaccinated, whereas physicians and administrative staff showed higher vaccination uptake. Presumed ineffectiveness of the vaccine is an important reason for non-vaccination.

References

  1. Covid-⁠19 Schweiz Coronavirus Dashboard [Internet]. [cited 2023 May 27]. Available from: https://www.covid19.admin.ch/de/epidemiologic/death
  2. Swiss School of Public Health. (SSPH+). Resultate von Corona Immunitas [Internet]. Corona Immunitas. 2023. Available from: https://www.corona-immunitas.ch/programm/resultate/
  3. Dörr T, Haller S, Müller MF, Friedl A, Vuichard D, Kahlert CR, et al. Risk of SARS-CoV-2 Acquisition in Health Care Workers According to Cumulative Patient Exposure and Preferred Mask Type. JAMA Netw Open. 2022 Aug;5(8):e2226816. 10.1001/jamanetworkopen.2022.26816 DOI: https://doi.org/10.1001/jamanetworkopen.2022.26816
  4. Pilishvili T, Fleming-Dutra KE, Farrar JL, Gierke R, Mohr NM, Talan DA, et al.; Vaccine Effectiveness Among Healthcare Personnel Study Team. Interim Estimates of Vaccine Effectiveness of Pfizer-BioNTech and Moderna COVID-19 Vaccines Among Health Care Personnel - 33 U.S. Sites, January-March 2021. MMWR Morb Mortal Wkly Rep. 2021 May;70(20):753–8. 10.15585/mmwr.mm7020e2 DOI: https://doi.org/10.15585/mmwr.mm7020e2
  5. Gómez-Ochoa SA, Franco OH, Rojas LZ, Raguindin PF, Roa-Díaz ZM, Wyssmann BM, et al. COVID-19 in Healthcare Workers: A Living Systematic Review and Meta-analysis of Prevalence, Risk Factors, Clinical Characteristics, and Outcomes. Am J Epidemiol. 2020Sep;kwaa191. DOI: https://doi.org/10.1093/aje/kwaa191
  6. Pilishvili T, Gierke R, Fleming-Dutra KE, Farrar JL, Mohr NM, Talan DA, et al. Effectiveness of mRNA Covid-19 Vaccine among U.S. Health Care Personnel. N Engl J Med. 2021 Sep 22;NEJMoa2106599. DOI: https://doi.org/10.1056/NEJMoa2106599
  7. Larson HJ, Jarrett C, Eckersberger E, Smith DM, Paterson P. Understanding vaccine hesitancy around vaccines and vaccination from a global perspective: a systematic review of published literature, 2007-2012. Vaccine. 2014 Apr;32(19):2150–9. 10.1016/j.vaccine.2014.01.081 DOI: https://doi.org/10.1016/j.vaccine.2014.01.081
  8. Lazarus JV, Ratzan SC, Palayew A, Gostin LO, Larson HJ, Rabin K, et al. A global survey of potential acceptance of a COVID-19 vaccine. Nat Med. 2021 Feb;27(2):225–8. 10.1038/s41591-020-1124-9 DOI: https://doi.org/10.1038/s41591-020-1124-9
  9. Lang P, Wu CT, Le-Nguyen AF, Czock A. Influenza Vaccination Behaviour of Healthcare Workers in Switzerland: A Cross-Sectional Study. Int J Public Health. 2023 Mar;68:1605175. 10.3389/ijph.2023.1605175 DOI: https://doi.org/10.3389/ijph.2023.1605175
  10. Influenza Vaccination Coverage Among Health-Care Personnel — 2011–12 Influenza Season, United States [Internet]. [cited 2023 Nov 5]. Available from: https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6138a1.htm
  11. Pless A, McLennan SR, Nicca D, Shaw DM, Elger BS. Reasons why nurses decline influenza vaccination: a qualitative study. BMC Nurs. 2017 Apr;16(1):20. 10.1186/s12912-017-0215-5 DOI: https://doi.org/10.1186/s12912-017-0215-5
  12. Fadda M, Bezani K, Amati R, Fiordelli M, Crivelli L, Albanese E, et al. Decision-making on COVID-19 vaccination: A qualitative study among health care and social workers caring for vulnerable individuals. SSM Qual Res Health. 2022 Dec;2:100181. 10.1016/j.ssmqr.2022.100181 DOI: https://doi.org/10.1016/j.ssmqr.2022.100181
  13. Zürcher K, Mugglin C, Egger M, Müller S, Fluri M, Bolick L, et al. Vaccination willingness for COVID-19 among healthcare workers: a cross-sectional survey in a Swiss canton. Swiss Med Wkly. 2021 Sep;151(3738):w30061–30061. 10.4414/SMW.2021.w30061 DOI: https://doi.org/10.4414/SMW.2021.w30061
  14. Baron RC, Risch L, Weber M, Thiel S, Grossmann K, Wohlwend N, et al. Frequency of serological non-responders and false-negative RT-PCR results in SARS-CoV-2 testing: a population-based study. Clin Chem Lab Med. 2020 Aug;58(12):2131–40. 10.1515/cclm-2020-0978 DOI: https://doi.org/10.1515/cclm-2020-0978
  15. Mahase E. Covid-19: two antibody tests are “highly specific” but vary in sensitivity, evaluations find. BMJ. 2020 May;369:m2066. 10.1136/bmj.m2066 DOI: https://doi.org/10.1136/bmj.m2066
  16. Schaffner A, Risch L, Aeschbacher S, Risch C, Weber MC, Thiel SL, et al. Characterization of a Pan-Immunoglobulin Assay Quantifying Antibodies Directed against the Receptor Binding Domain of the SARS-CoV-2 S1-Subunit of the Spike Protein: A Population-Based Study. J Clin Med. 2020 Dec;9(12):3989. 10.3390/jcm9123989 DOI: https://doi.org/10.3390/jcm9123989
  17. Bergeri I, Whelan MG, Ware H, Subissi L, Nardone A, Lewis HC, et al.; Unity Studies Collaborator Group. Global SARS-CoV-2 seroprevalence from January 2020 to April 2022: A systematic review and meta-analysis of standardized population-based studies. PLoS Med. 2022 Nov;19(11):e1004107. 10.1371/journal.pmed.1004107 DOI: https://doi.org/10.1371/journal.pmed.1004107
  18. Jacot D, von Rotz U, Blondet F, Aebischer O, Matthieu P, De Rham M, et al. SARS-CoV-2 seroprevalence in hospital healthcare workers in Western Switzerland at the end of the second pandemic wave. J Med Microbiol. 2022 Aug;71(8):001558. 10.1099/jmm.0.001558 DOI: https://doi.org/10.1099/jmm.0.001558
  19. Carazo S, Skowronski DM, Brisson M, Barkati S, Sauvageau C, Brousseau N, et al. Protection against omicron (B.1.1.529) BA.2 reinfection conferred by primary omicron BA.1 or pre-omicron SARS-CoV-2 infection among health-care workers with and without mRNA vaccination: a test-negative case-control study. Lancet Infect Dis. 2023 Jan;23(1):45–55. 10.1016/S1473-3099(22)00578-3 DOI: https://doi.org/10.1016/S1473-3099(22)00578-3
  20. Hui DS. Hybrid immunity and strategies for COVID-19 vaccination. Lancet Infect Dis. 2023 Jan;23(1):2–3. 10.1016/S1473-3099(22)00640-5 DOI: https://doi.org/10.1016/S1473-3099(22)00640-5
  21. Babouee Flury B, Güsewell S, Egger T, Leal O, Brucher A, Lemmenmeier E, et al.; SURPRISE Study Group. Risk and symptoms of COVID-19 in health professionals according to baseline immune status and booster vaccination during the Delta and Omicron waves in Switzerland-A multicentre cohort study. PLoS Med. 2022 Nov;19(11):e1004125. 10.1371/journal.pmed.1004125 DOI: https://doi.org/10.1371/journal.pmed.1004125
  22. Kohler P, Babouee Flury B, Güsewell S, Egger T, Leal O, Brucher A, et al.; SURPRISE Study Group. Clinical symptoms of SARS-CoV-2 breakthrough infection during the Omicron period in relation to baseline immune status and booster vaccination-A prospective multicentre cohort of health professionals (SURPRISE study). Influenza Other Respir Viruses. 2023 Jun;17(6):e13167. 10.1111/irv.13167 DOI: https://doi.org/10.1111/irv.13167
  23. Irving SA, Buchan SA. Considerations of hybrid immunity and the future of adolescent COVID-19 vaccination. Lancet Infect Dis. 2023 Apr;23(4):382–3. 10.1016/S1473-3099(22)00759-9 DOI: https://doi.org/10.1016/S1473-3099(22)00759-9
  24. Spinardi JR, Srivastava A. Hybrid Immunity to SARS-CoV-2 from Infection and Vaccination-Evidence Synthesis and Implications for New COVID-19 Vaccines. Biomedicines. 2023 Jan;11(2):370. 10.3390/biomedicines11020370 DOI: https://doi.org/10.3390/biomedicines11020370
  25. Abbas M, Robalo Nunes T, Cori A, Cordey S, Laubscher F, Baggio S, et al. Explosive nosocomial outbreak of SARS-CoV-2 in a rehabilitation clinic: the limits of genomics for outbreak reconstruction. J Hosp Infect. 2021 Nov;117:124–34. 10.1016/j.jhin.2021.07.013 DOI: https://doi.org/10.1016/j.jhin.2021.07.013
  26. Cormier H, Brangier A, Lefeuvre C, Asfar M, Annweiler C, Legeay C. Lessons learnt from a nosocomial COVID-19 outbreak in a geriatric acute care ward with a high attack rate. Maturitas. 2021 Jul;149:34–6. 10.1016/j.maturitas.2021.05.001 DOI: https://doi.org/10.1016/j.maturitas.2021.05.001
  27. Abbas M, Cori A, Cordey S, Laubscher F, Robalo Nunes T, Myall A, et al. Reconstruction of transmission chains of SARS-CoV-2 amidst multiple outbreaks in a geriatric acute-care hospital: a combined retrospective epidemiological and genomic study. eLife. 2022 Jul;11:e76854. 10.7554/eLife.76854 DOI: https://doi.org/10.7554/eLife.76854
  28. Feikin DR, Higdon MM, Abu-Raddad LJ, Andrews N, Araos R, Goldberg Y, et al. Duration of effectiveness of vaccines against SARS-CoV-2 infection and COVID-19 disease: results of a systematic review and meta-regression. Lancet. 2022 Mar;399(10328):924–44. 10.1016/S0140-6736(22)00152-0 DOI: https://doi.org/10.1016/S0140-6736(22)00152-0
  29. Dzinamarira T, Tungwarara N, Chitungo I, Chimene M, Iradukunda PG, Mashora M, et al. Unpacking the Implications of SARS-CoV-2 Breakthrough Infections on COVID-19 Vaccination Programs [Internet]. Vaccines (Basel). 2022 Feb;10(2):252. [cited 2023 Nov 1] Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8879800/ 10.3390/vaccines10020252 DOI: https://doi.org/10.3390/vaccines10020252
  30. Zaçe D, La Gatta E, Petrella L, Di Pietro ML. The impact of COVID-19 vaccines on fertility-A systematic review and meta-analysis. Vaccine. 2022 Oct;40(42):6023–34. 10.1016/j.vaccine.2022.09.019 DOI: https://doi.org/10.1016/j.vaccine.2022.09.019
  31. Politis M, Sotiriou S, Doxani C, Stefanidis I, Zintzaras E, Rachiotis G. Healthcare Workers’ Attitudes towards Mandatory COVID-19 Vaccination: A Systematic Review and Meta-Analysis. Vaccines (Basel). 2023 Apr;11(4):880. 10.3390/vaccines11040880 DOI: https://doi.org/10.3390/vaccines11040880
  32. Gagneur A, Battista MC, Boucher FD, Tapiero B, Quach C, De Wals P, et al. Promoting vaccination in maternity wards ─ motivational interview technique reduces hesitancy and enhances intention to vaccinate, results from a multicentre non-controlled pre- and post-intervention RCT-nested study, Quebec, March 2014 to February 2015. Euro Surveill. 2019 Sep;24(36):1800641. 10.2807/1560-7917.ES.2019.24.36.1800641 DOI: https://doi.org/10.2807/1560-7917.ES.2019.24.36.1800641
  33. Shrestha NK, Burke PC, Nowacki AS, Simon JF, Hagen A, Gordon SM. Effectiveness of the Coronavirus Disease 2019 Bivalent Vaccine. Open Forum Infect Dis. 2023 Apr;10(6):ofad209. 10.1093/ofid/ofad209 DOI: https://doi.org/10.1093/ofid/ofad209
  34. Nakagama Y, Komase Y, Kaku N, Nitahara Y, Tshibangu-Kabamba E, Tominaga T, et al. Detecting Waning Serological Response with Commercial Immunoassays: 18-Month Longitudinal Follow-up of Anti-SARS-CoV-2 Nucleocapsid Antibodies. Microbiol Spectr. 2022 Aug;10(4):e0098622. 10.1128/spectrum.00986-22 DOI: https://doi.org/10.1128/spectrum.00986-22

Most read articles by the same author(s)

<< < 1 2 3 4 > >>