Vaccine Mandates: New Questions

Allyson Pollock, Carl Heneghan, and Paula Byrne discuss key policy questions around vaccine mandates

Following public outcry, the requirement for NHS healthcare workers (HCWs) and social care staff to be fully vaccinated by April 1, 2022, has been paused, and the government consultation with a view to revoking current regulations in England ended on February 16. However, the matter is far from over, as the Secretary of State for Health and Social Care in England has now written to professional regulators to ask them to review current guidance on vaccinations and to emphasise professional responsibilities. He has also asked the NHS to review its policies on the hiring of and deployment of staff, taking their vaccination status into account. His officials have also been asked to consult on updating and strengthening requirements in relation to his Department’s code of practice, which applies to all Care Quality Commission-registered providers of healthcare and social care settings in England.1

It is therefore timely to set out some of the key questions and evidence that policy makers need to address in advance of reviewing their policies.

Are there alternative strategies to increase vaccination uptake?

Current vaccine uptake in the UK is exceptionally high, with over 90% of NHS and social care staff doubly vaccinated. If mandates are the preferred option, alternatives to increasing uptake further should have been tried and shown consistently not to work. A scoping review of systematic reviews identified 48 different interventions to increase vaccine uptake with multi-component interventions educational and/or reminder interventions showing higher vaccine uptake compared with controls in most studies.2

Is there high-quality evidence that vaccine mandates work?

A systematic review of mandatory vaccines in HCWs suggested that while mandates increased vaccination rates, no studies reported infections or clinical outcomes in HCW with mandates.3 Of the twelve studies included in the review, none were randomised, and the majority had at least one indication of increased risk of bias. Crucially, vaccination rates prior to introduction of the mandate were as low as 30%, with only one study having a baseline of greater than 90% of people vaccinated.

Is there durable protection from infection?

While vaccines have effectively reduced admissions and deaths, despite high vaccination rates in Europe, Omicron is evading protection conferred by double vaccines, although boosters give some benefit.4,5 Since June 2021, most infections, hospitalisations, and deaths from Covid-19 in the UK have been in the vaccinated, although rates are higher in those who are unvaccinated.6  These observational data are not measures of vaccine effectiveness as they do not take account of confounding and differences in group exposure to behavioural, socioeconomic, and environmental factors. For example, vaccine uptake is lower among the poor and some ethnic groups and unvaccinated people have a much greater risk of death from all other causes than Covid, than vaccinated people.7  Reinfections too are increasing and according to UKHSA accounted for around 10% of infections regardless of vaccination status.

Is the mandated intervention risk-free?

As the average age of HCWs is 45 years, the risks of Covid-19 and, therefore, the benefits of vaccination in this group are much less than in the general population; moreover, vaccine harms, for example, from increased risk of myocarditis, are not well-documented, and longer-term harms are, as yet, unknown.8 In addition, efficacy from boosters unknown due to absence of controlled trials.

Is there evidence the vaccine prevents onward transmission?

The primary concern is that an unvaccinated HCW may transmit SARS-CoV-2 to a patient. Real-world data show that the fully vaccinated constitute a significant source of transmission; countries with the highest percentage of fully vaccinated are currently classified as ‘high’ transmission countries.4  In the UK, although 88% of the population over 18 years have received two vaccine doses, an estimated 12 million people in England contracted Omicron in the four weeks to January 29, 2022.9

Observational studies into transmission risk yield mixed findings and  are subject to bias.10-12  Transmission dynamics are complex. As SARS-CoV-2 enters the upper respiratory tract (URT),13,14 those with prior immunity will be better able to mount a swift immune reaction against reinfection. However, the immune response to an intramuscular vaccination induces a weak or no mucosal response in the URT, 13,15-17 and there is uncertainty if this prevents viral shedding.18

Writing in The Lancet, Carlos Franco Peredes says ‘A recent investigation by the US Centers for Disease Control and Prevention of an outbreak of COVID-19 in a prison in Texas showed the equal presence of infectious virus in the nasopharynx of vaccinated and unvaccinated individuals. Similarly, researchers in California observed no major differences between vaccinated and unvaccinated individuals in terms of SARS-CoV-2 viral loads in the nasopharynx, even in those with proven asymptomatic infection.’

Thus, the current evidence suggests that current mandatory vaccination policies might need to be reconsidered.

Are there alternative strategies to prevent transmission?

Good quality PPE, worn correctly and targeted testing may have the potential to reduce transmission. However, there is a need for large, well‐designed RCTs addressing the effectiveness of many of these interventions as alternative strategies .19

Will the mandate protect health services?

Another overlooked factor is that many HCWs will already have been infected. Immunity, including immune memory, following infection, appears to be long-lasting; reinfections, when they occur, generally are milder.9,20-23 Moreover, reinfection is increasingly common. Extrapolating results from a clinical trial24 to the approximately 80,000 staff who remain unvaccinated suggests that it would prevent eleven additional cases of severe disease in England. Milder variants, previous infection history, and HCWs being a younger cohort than trial participants would reduce this further. 

Will the vaccine mandate harm health services?

In a study to determine predictors of support for mandatory seasonal influenza vaccination, 72% of employees thought an influenza vaccine mandate was coercive, and 18% thought it violated their contract.25 An estimated 40,000 care home workers have lost their jobs over the policy – many may not return.1 The potential NHS workforce loss may be up to 80,000.



The WHO considers mandates to be the ‘absolute last resort’.26 A core component of the long-term NHS plan is shared decision making, ‘a joint process in which a healthcare professional works together with a person to reach a decision about care’.27

The questions we pose highlight the ways in which shared decisions for HCWs are being abandoned and how alternative evidence-based interventions have been overlooked. Current evidence does not support the imposition of mandates for HCWs,28,29 nor does it justify overturning a century of vaccine policy built on trust and informed decisions.


  1. UK Parliament Commons Chamber. Vaccination: Condition of Deployment; Volume 708: debated on Monday 31 January 2022. 2022.
  2. Heneghan C, Plüddemann A, Spencer E, Brassey J, Rosca E, Onakpoya I, et al. Interventions designed to improve vaccination uptake: Scoping review of systematic reviews and meta-analyses-protocol (version 1). medRxiv. 2021.
  3. Pitts SI, Maruthur NM, Millar KR, Perl TM, Segal J. A systematic review of mandatory influenza vaccination in healthcare personnel. American journal of preventive medicine. 2014;47(3):330-40.
  4. Kampf G. The epidemiological relevance of the COVID-19-vaccinated population is increasing. Lancet Reg Health Eur. 2021;11:100272.
  5. World Health Organization. Enhancing response to Omicron SARS-CoV-2 variant 07 January 2022. Available from: https://www.who.int/publications/m/item/enhancing-readiness-for-omicron-(b.1.1.529)-technical-brief-and-priority-actions-for-member-states.
  6. Intensive Care National Audit and Research Centre. ICNARC report on COVID-19 in critical care: England, Wales and Northern Ireland 28 January 2022 2022. Available from: https://www.icnarc.org/Our-Audit/Audits/Cmp/Reports.
  7. Dorling D. Who are the unvaccinated and what’s happening to them? Available from: https://www.dannydorling.org/?p=8715.
  8. Demasi M. 2022. Available from: https://maryannedemasi.com/publications/f/myocarditis-post-vaccination-%E2%80%93-should-we-be-concerned.
  9. Office for National Statistics. Coronavirus (COVID-19) infection survey headline results, UK: 19 January 2022 2022. Available from: https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/19january2022.
  10. UK Health Security Agency. Covid-19 vaccine surveillance report Week 47 2021. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1036047/Vaccine_surveillance_report_-_week_47.pdf.
  11. Gov.uk. One dose of COVID-19 can cut household transmission by up to half 2021. Available from: https://www.gov.uk/government/news/one-dose-of-covid-19-vaccine-can-cut-household-transmission-by-up-to-half.
  12. Singanayagam A, Hakki S, Dunning J, Madon KJ, Crone MA, Koycheva A, et al. Community transmission and viral load kinetics of the SARS-CoV-2 delta (B.1.617.2) variant in vaccinated and unvaccinated individuals in the UK: a prospective, longitudinal, cohort study. The Lancet Infectious Diseases. 2021.
  13. Russell MW, Moldoveanu Z, Ogra PL, Mestecky J. Mucosal immunity in COVID-19: A neglected but critical aspect of SARS-CoV-2 infection. Frontiers in Immunology. 2020;11:3221.
  14. Cervia C, Nilsson J, Zurbuchen Y, Valaperti A, Schreiner J, Wolfensberger A, et al. Systemic and mucosal antibody responses specific to SARS-CoV-2 during mild versus severe COVID-19. Journal of Allergy and Clinical Immunology. 2021;147(2):545-57. e9.
  15. Gallo O, Locatello LG, Mazzoni A, Novelli L, Annunziato F. The central role of the nasal microenvironment in the transmission, modulation, and clinical progression of SARS-CoV-2 infection. Mucosal immunology. 2021;14(2):305-16.
  16. Sano K, Bhavsar D, Singh G, Floda D, Srivastava K, Gleason C, et al. Efficient mucosal antibody response to SARS-CoV-2 vaccination is induced in previously infected individuals. medRxiv. 2021:2021.12.06.21267352.
  17. Zhao J, Zhao J, Mangalam AK, Channappanavar R, Fett C, Meyerholz DK, et al. Airway memory CD4+ T cells mediate protective immunity against emerging respiratory coronaviruses. Immunity. 2016;44(6):1379-91.
  18. Veldhoen M, Simas JP. Endemic SARS-CoV-2 will maintain post-pandemic immunity. Nature Reviews Immunology. 2021;21(3):131-2.
  19. Jefferson T, Jones M, Al Ansari LA, Bawazeer G, Beller E, Clark J, et al. Physical interventions to interrupt or reduce the spread of respiratory viruses. Part 1-Face masks, eye protection and person distancing: systematic review and meta-analysis. MedRxiv. 2020.
  20. Health Information and Quality Authority. Duration of immunity; protection from reinfection following SARS-CoV-2 infection2021. Available from: https://www.hiqa.ie/sites/default/files/2021-11/Duration-of-protective-immunity-evidence-summary_0.pdf.
  21. Gazit S, Shlezinger R, Perez G, Lotan R, Peretz A, Ben-Tov A, et al. Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections. MedRxiv  2021. Available from: https://www.medrxiv.org/content/10.1101/2021.08.24.21262415v1.
  22. Kojima N, Klausner JD. Protective immunity after recovery from SARS-CoV-2 infection. The Lancet Infectious Diseases. 2022;22(1):12-4.
  23. Alejo JL, Mitchell J, Chang A, Chiang TPY, Massie AB, Segev DL, et al. Prevalence and Durability of SARS-CoV-2 Antibodies Among Unvaccinated US Adults by History of COVID-19. JAMA. 2022.
  24. European Medicines Agency. Assessment report: Comirnaty; Common name; Covid-19 mRNA vaccine (nucleoside-modified); Procudeure No. EMEA/H/C/005735/0000. 2021.
  25. Feemster KA, Prasad P, Smith MJ, Feudtner C, Caplan A, Offit P, et al. Employee designation and health care worker support of an influenza vaccine mandate at a large pediatric tertiary care hospital. Vaccine. 2011;29(9):1762-9.
  26. Klassen T. Carrots, sermons, sticks:Vaccine mandates face opposition around the globe. The Conversation. 2022. Available from: https://theconversation.com/carrots-sermons-sticks-vaccine-mandates-face-opposition-around-the-globe-174749.
  27. Duggan J. NHS vaccine mandate: ‘Our stress levels have peaked, our mental health has hit rock bottom’. iNews. 2022. Available from: https://inews.co.uk/news/nhs-vaccine-mandate-care-home-workers-lost-jobs-jab-u-turn-staff-rules-1433303.
  28. UK Medical freedom Alliance. Covid-19 Vaccine- Informed Consent Legal Summary 2020. Available from: https://www.ukmedfreedom.org/open-letters/covid-19-vaccine-informed-consent-legal-summary.
  29. Irish Council for Civil Liberties. Covid-19 emergency powers: we’ve got this. 2020. Available from: https://www.iccl.ie/human-rights/covid-19-emergency-legislation-everything-you-need-to-know/.