Social Vulnerability to Credit for Many COVID-19 Health Disparities

It’s broadly accepted that the COVID-19 pandemic was characterized by stark health disparities, with those experiencing the greatest social vulnerability also seeing the worst pandemic outcomes. Now, data from the Regenstrief Institute takes that a step further by demonstrating that it is that very social vulnerability that’s partly responsible for COVID-19 health disparities.

The researchers proved this by showing that COVID-19 vaccine efficacy was around the same across all sociodemographics, but COVID-19 outcomes were not. That’s not because the COVID shots didn’t work as well on socially vulnerable people, study co-author Brian Dixon, PhD, MPA, stated publicly.

“We found that protection against emergency room and urgent care center visits, hospitalization and death conveyed by a COVID-19 mRNA vaccination did not vary by social vulnerability,” Dixon explained in the press release.

“But because social vulnerability did play a role in whether individuals are vaccinated or not –- and socially vulnerable communities have lesser vaccine coverage –- socially vulnerable individuals and their communities are bearing a larger burden during the pandemic,” Dixon continued. “They are having poorer outcomes as they are less likely to be vaccinated.”

The researchers looked at EHR data from seven different health systems to look at vaccination status for folks treated for COVID-19. The team also looked at address information from patient records to assess social vulnerability, defined using the CDC and Agency for Toxic Substances and Disease Registry Social Vulnerability Index (SVI).

By and large, COVID-19 vaccination was higher among those with lower SVIs than those with more social vulnerability. As of July 2021, 56 percent of those with the lowest social vulnerability were vaccinated compared to 36 percent of those with the highest social vulnerability.

That trend persisted into February 2022, when people became eligible for COVID-19 booster shots. At that time, 43 percent of the least socially vulnerable people had gotten the boosters compared to 30 percent of the most socially vulnerable.

Those differences in vaccination rates are likely the reason behind COVID-19 health disparities because once people got the shots, their social vulnerability didn’t influence outcomes. Across everyone who was vaccinated, vaccine efficacy was about the same regardless of social vulnerability.

What’s more, an individual’s social vulnerability may have been behind their vaccination status, although the researchers did not investigate reasons for not getting the COVID shots. But it’s pretty typical for those experiencing social vulnerability to face a number of social determinants of health that limit care access, according to co-author Katie Allen, BS, a data scientist with the Regenstrief Institute.

“Socially vulnerable individuals may live in densely populated buildings and neighborhoods, travel via crowded public transportation and often hold jobs that are not conducive to remote work. So, they are more susceptible to catching COVID,” Allen said in the press release. “And they may not have the resources to seek medical care when they are getting sick, leading to adverse medical outcomes.”

That means that, in order to close lingering COVID-19 health disparities, public health officials will need to improve vaccination rates in traditionally underserved populations.

“Initial COVID-19 vaccination coverage remains lower in communities with higher social vulnerability and booster rates are even lower,” Dixon said. “This study shows the need to focus public health efforts on vaccine coverage as well as vaccine effectiveness.”