As Covid-19 continues to exact a heavy toll, development of a vaccine appears the most promising means of restoring normalcy to civil life. Perhaps no scientific breakthrough is more eagerly anticipated. But bringing a vaccine to market is only half the challenge; also critical is ensuring a high enough vaccination rate to achieve herd immunity. Concerningly, a recent poll found that only 49% of Americans planned to get vaccinated against SARS-CoV-2.1
One option for increasing vaccine uptake is to require it. Mandatory vaccination has proven effective in ensuring high childhood immunization rates in many high-income countries. However, except for influenza vaccination of health care workers, mandates have not been widely used for adults.
Although a vaccine remains months to years away, developing a policy strategy to ensure uptake takes time. We offer a framework that states can apply now to help ensure uptake of the vaccine when it becomes available — including consideration of when a mandate might become appropriate. Our approach is guided by lessons from U.S. experiences with vaccines for the 1976 "swine flu," H1N1 influenza, smallpox, and human papillomavirus (HPV).
We believe that six substantive criteria should be met before a state imposes a SARS-CoV-2 vaccine mandate (see box). The first is the existence of evidence that Covid-19 is inadequately controlled in the state by other measures, such as testing, contact tracing, and isolation and quarantine — as indicated by sustained, troubling trends in new cases, hospitalizations, or deaths. Principles of public health law and ethics require that interventions that impinge on autonomy be reasonable and necessary; therefore, Covid-19 must present an ongoing threat. By the time a vaccine is available, more will be known about natural immunity in the population, the consequences of relaxing community mitigation measures, and the feasibility of scaling up test-and-trace strategies. There should be a reasonable indication as to whether further measures are needed.