Although the COVID-19 vaccine rollout is unprecedented in speed and scope, the process of postapproval surveillance has been shown to be robust and should serve as a source of reassurance to the public regarding the effectiveness of the initial and follow-up review process.
Vaccination against infectious diseases has had a remarkably beneficial impact on mortality and disability resulting from these illnesses.1-3 The implementation of vaccine strategies has been successful in dramatically reducing or even eliminating the risk of serious public health conditions, such as rubella, poliomyelitis, measles, pertussis, and mumps.
Unfortunately, not all people recognize this success or the need for vaccines that prevent infections with these dangerous pathogens. The history of vaccination hesitancy is long. In much earlier times, there was legitimate concern for both the safety and efficacy of proposed vaccine products due to the lack of a rigorous clinical trials process and formal regulatory review by experts in vaccine science, epidemiology, and statistical analysis. More recently, however, with our far greater understanding of the biology of infectious diseases, the establishment of robust and well-validated clinical trial strategies for evaluating vaccine products and scrupulous review by both governmental health agencies and external experts, the utility of a given vaccine is clear before it is approved. Mandatory reporting of adverse effects following use in the real world ensures that rare or longer-term concerns are appropriately evaluated.
Consider, for example, findings from a recent review of 57 vaccines that the FDA approved from January 1, 1996, to December 31, 2015. More than 90% of the vaccines were supported by data from randomized controlled trials, each involving a median of more than 4100 study participants.4 The authors noted that the postsurveillance mechanism worked well, with a total of 58 safety-related modifications added to the FDA-approved vaccine labels involving approximately half of the vaccines (n = 25). Most of the changes related to additional warnings that stemmed from extended experience with the vaccine. A total of 8 contraindications were added to the labels, and only 1 vaccine product was withdrawn from the market due to safety-related issues.
Restrictions on the patient populations who should be eligible to receive the vaccine was the most common change mandated by the FDA, with additional notification regarding potential allergic reactions being the second most common issue arising from follow-up review. The investigators concluded: “Over a 20-year period, vaccines were found to be remarkably safe. A large proportion of safety issues were identified through existing postmarketing surveillance programs and were of limited clinical significance. These findings confirm the robustness of the vaccine approval system and postmarketing surveillance.”4
Following the introduction of several COVID-19 vaccines, there were reports of a rare blood-clotting disorder associated with at least 2 of the products in noninvestigative real-world use. The events were quickly evaluated, with public health agencies making recommendations for the future delivery of these vaccines. Although the COVID-19 vaccine rollout is unprecedented in speed and scope, the process of postapproval surveillance has been shown to be robust and should serve as a source of reassurance to the public regarding the effectiveness of the initial and follow-up review process.
Unfortunately, this is an oversimplified view of the entire spectrum of the vaccination process. In a most provocative commentary, Naomi Oreskes, PhD, a professor of the history of science at Harvard University, noted that we should perhaps reassess the nature of the difficulty associated with developing and implementing an effective vaccination strategy.5 The author highlights the fact we have traditionally considered problems to be “hard” that are associated with major technological challenges or an understanding of highly complex theories (eg, quantum physics). The development of several highly effective COVID-19 vaccines and their release for noninvestigative administration less than 1 year follow-ing the identification of the molecular structure of the causative virus is nothing short of remarkable, yet we have struggled until recently to implement a nationwide vaccine distribution strategy. What good is a vaccine that remains in a vial rather than being injected into the arm of an individual susceptible to a COVID-19 infection?
Oreskes concludes: “We call the physical sciences ‘hard’ because they deal with issues that are mostly independent of the vagaries of human nature; they offer laws that (at least in the right circumstances) yield exact answers. But physics and chemistry will never tell us how to design an effective vaccination program…in part because they do not help us comprehend human behavior. The social sciences rarely yield exact answers. But that does not make them easy.”5
Although the COVID-19 vaccines must be regarded as truly remark-able scientific success stories,6 we are faced with the reality of human behavior, and we are learning that overcoming obstacles to existing and firmly entrenched beliefs, reinforced by social media sources and conspiracy theories, will be hard.7,8
We should recognize that this conclusion also pertains to the admin-istration of vaccines that have been documented to be both safe and highly effective in the prevention of cancer. We now have conclu-sive evidence that vaccination against the human papillomavirus (HPV) can substantially reduce the risk of developing invasive cervi-cal cancer.9 However, recent self-reported data reveal that, among 12,644 women and men aged 18 to 21 years in the United States, only 55% of women and 34% of men had received at least 1 dose of the HPV vaccine.10 Clearly, we have a long way to go to solve this “hard” prob-lem of increasing the delivery of this critically important cancer prevention strategy.