SARS-CoV-2 vaccine protection and deaths among US veterans during 2021

In Cohn et. al., Science, 2021, the authors provide no evidence that vaccine mandates or passports will achieve disease control, yet it is concluded that "It is essential to implement public health interventions, such as strategic testing for control of outbreaks, vaccine passports, employment-based vaccine mandates, vaccination campaigns for eligible children as well as adults, and consistent messaging from public health leadership in the face of increased risk of infection due to the Delta and other emerging variants."

This is thus a surprising conclusion. The implementation of employer mandates or passports requires additional evidence through observational data or modelling that demonstrates a clear benefit, even when weighed against the potential harms of these policies.

It is not immediately obvious whether employer mandates or vaccine passports would reduce disease risk. (I here assume that a reasonable risk to consider could be that of (severe) disease caused by the unvaccinated onto the vaccinated and that this should be an intolerable increase in absolute risk weighed against policy harms.) Any such calculation of the putative benefits of mandates or passports should at least account for: the relative proportions of vaccinated versus unvaccinated in relevant populations; the possibility that passports and mandates may increase the perception of safety, leading to a false sense of security which could be harmful to at-risk (vaccinated or exempt) workers; the level of natural immunity likely in the unvaccinated population [1]; and the difference in epidemiological promiscuity between infected vaccinated and infected unvaccinated individuals (as Covid-19 vaccines reduce the severity of symptoms [2], it is not unreasonable to suppose that an infected vaccinated individual may engage in more `risky' interactions than an infected unvaccinated person, all else equal). 

Once this absolute risk has been estimated for mandated versus non-mandated settings, it must be balanced against the multiple potential public health harms of vaccine mandates and passports. These harms include that these policies are likely to indirectly discriminate against race. In both the UK and US, for example, Black communities are overall less willing to receive a COVID-19 vaccine [3-5]. Moreover, in a UK context, vaccine passports have been shown to make the majority of people who do not state a firm intention to vaccinate (or not) less inclined to vaccinate [3, 6]. Although many of these individuals will likely go on to vaccinate regardless of a stated survey response, it is unclear whether this process is ethical: is it ethical if people take the vaccine solely to resume elements of society (such as the workplace) if they do not wish to take the vaccine? When a loss of household income via a job loss is involved, this ethical question becomes more important.

There are further harms to consider too. If passports or mandate policies drive lower vaccine confidence among populations who are reluctant to vaccinate, do we stand to damage trust in governments, policymakers, public health institutions and, ultimately, in vaccines? As confidence in vaccines is lowest among the young in many settings around the world, it is not unreasonable to speculate that we may lower trust in routine immunisations among key demographics, as loss of confidence in one vaccine can trigger losses in others [7].

[1] Vaccinating people who have had covid-19: why doesn’t natural immunity count in the US? BMJ 374:n2101 (2021)https://doi.org/10.1136/bmj.n2101

[2] Antonelli et. al. Lancet Infectious Diseases (2021) https://doi.org/10.1016/S1473-3099(21)00460-6

[3] de Figueiredo et. al. EClinicalMedicine (2021). https://doi.org/10.1016/j.eclinm.2021.101109

[4] Woolf et. al. Lancet Regional Health Europe 9; 100180 (2021). https://doi.org/10.1016/j.lanepe.2021.100180

[5] Latest Data on COVID-19 Vaccinations by Race/Ethnicity Kaiser Family Foundation

https://www.kff.org/coronavirus-covid-19/issue-brief/latest-data-on-covid-19-vaccinations-by-race-ethnicity/ (2021)

[6] Porat et. al. Vaccines 9; 8 (2021) https://doi.org/10.3390/vaccines9080902

[7] de Figueiredo et. al. Lancet 396;10255 (2020) https://doi.org/10.1016/S0140-6736(20)31558-0