COVID-19 Epidemiology Explained: Success Becomes a Challenge

Vaccine compliance has been a growing challenge for the medical and public health infrastructure. Particularly, reductions in childhood vaccinations in various parts of the country have led to outbreaks in measles. As we look to mobilize the COVID-19 vaccine for the general public in 2021, it would be helpful to consider one of the theories for the decline in public acceptance, and how we can take this into account moving forward.

Here, we can look to the health belief model. What motivates people to make the health decisions that they make? Behavioral epidemiologists point to four key factors: perceived susceptibility, perceived severity, perceived benefits, and perceived barriers.

• Perceived Susceptibility—How likely am I to be affected?
• Perceived Severity—If I am affected, how bad would it be?
• Perceived Benefits—If I take action to prevent this, what are the benefits to me?
• Perceived Barriers—How hard would it be to overcome the barriers from this change?

“Perception” is a recurring concept in this decision-making process. It would be incorrect to assume that the entire public will be receptive to a medical procedure such as a vaccine after the medical and public health community recommend it. A multitude of factors go into this decision. For instance, who else and how many people do I know that has had this? And, when they had it, how bad was it? With benefits and barriers, people make an internal pro vs. con decision where they may believe that the benefits do not outweigh the barriers.

Let’s put this into context of the drop-in vaccination rates, particularly for childhood vaccines. One of the most common anti-vaccination rationales is from a study linking vaccines to autism and asthma. A point noted on the Senate floor by Elizabeth Warren regarding vaccinations was that “Our success may become our failure.” Warren was referencing that due to childhood vaccines we have seen dramatic increases in the infections that the MMR vaccine is intended to prevent. However, in the past few decades we’ve seen increases in autism and asthma. This impacts the public’s perceived susceptibility and severity of infection in conjunction with common ailments we increasingly see in the United States.

Outside of efficacy of the vaccine, we must also consider the health belief model in relation to COVID-19. Perceived susceptibility and severity will matter. Do we know people that have had COVID-19? If so, how bad was it? We must contend with the myth that vaccines cause the disease they are meant to prevent, as well as some public distrust of the health care infrastructure.

In this case, mass distribution of the COVID-19 vaccine will be delayed. Frontline health care professionals, first responders, and the most vulnerable will be prioritized. This will give the public more factors to consider when they make the decision themselves.