vaccines

The ‘Spillover’ Effect of Politicized COVID-19 Vaccines

In a new commentary in the Nature journal npj Vaccines, Matt Motta explains how public opposition to COVID-19 vaccines may lead to negative public opinion about other vaccines, and spur a demand for anti-vaccine policies.

At the outset of the COVID-19 pandemic, Democrats and Republicans planned to receive an (at the time) hypothetical COVID-19 vaccine at similar rates. Now, two years into the country’s highly polarized COVID-19 vaccination efforts, polling shows that Republicans are much less likely than Democrats to receive any vaccine.

This “COVID-19 vaccine spillover” not only threatens to further politicize Americans’ vaccine attitudes and behaviors, but it also may pose a challenge to evidence-based vaccine policy, writes Matthew Motta, assistant professor of health law, policy & management, in a new commentary.

Published in npj Vaccines, a journal of the Nature Portfolio, the commentary presents evidence that negative public opinion of COVID vaccines may be shaping similar public opposition towards mandates for childhood vaccines such as measles, mumps and rubella (MMR), which is currently required for children attending schools and daycares in all 50 states and Washington, DC. 

Pointing to data from the federally run Vaccine Adverse Event Reporting System (VAERS), Motta argues that the site’s compilation of reports of negative, vaccine-related side effects may actually serve as an indicator of public vaccine sentiment.

“While VAERS data cannot tell us precisely how many Americans hold positive or negative views toward vaccination, increased side effect reporting may be indicative of increased public fears about vaccine safety,” Motta writes. As an example, he examines data comparing average weekly reported side effects for the childhood vaccines MMR and MMRV, across red and blue states, from 2006 through Fall 2022.

Trend lines reported in the commentary shows a marked difference in partisan reporting of MMR and MMRV side effects after COVID-19 vaccines became available to the general public in early 2021.

“While red states were more likely to register adverse event reports than blue states prior to the availability of a COVID-19 vaccine, these differences spiked dramatically following vaccine rollout,” writes Motta.

He also provides strategies that researchers can embrace to identify whether politicized opposition to COVID-19 vaccines are extending to childhood vaccine mandates. Some of these strategies are: longitudinal assessments that could capture changes in public attitude among the same people over time; experimental studies that pose COVID vaccine and MMR vaccine questions separately to participants; and observational studies that could provide insight into other factors that may shape one’s views on childhood vaccinations, such as religious views, educational background, or access to healthcare.

“Researchers have three useful tools at their disposal for making an effort to document whether or not politicized views toward COVID-19 vaccines are shaping public support for childhood vaccine mandates more generally,” Motta writes. “Determining whether or not this is the case is vitally important, as it can help policymakers to preempt potential political challenges to policies encouraging universal childhood vaccination.”

Click here to read the full commentary.