Community Factors Affect Risk of Breakthrough SARS-CoV-2 in Vaccinated Adults

The risk of SARS-CoV-2 infection in vaccinated US adults is higher for those who live in rural areas and in counties with high vaccine hesitancy, according to a study published in PLOS One.

“Our findings suggest that vaccinated persons dwelling in communities with certain characteristics, such as high vaccine hesitancy, are at a greater risk of breakthrough infections, despite being vaccinated, compared with persons in communities without those risk factors,” wrote corresponding author Alfred Jerrod Anzalone, MS, of the University of Nebraska Medical Center in Omaha, and coauthors. “Public health messaging should highlight this point and emphasize the high importance of precautionary measures (eg, mask wearing, social distancing).”

The retrospective cohort study included 566,128 vaccinated adults and 1.7 million adults without documented vaccination in the United States between January 1, 2021, and December 20, 2021. Using models that adjusted for comorbid conditions and other differences, investigators looked at the impact of rurality, county vaccine hesitancy, and county vaccination rates on the risk of breakthrough infection in the 6 months following two mRNA COVID-19 vaccinations.

Compared with fully vaccinated adults living in urban areas, adjusted hazard ratios for breakthrough infection were 1.53 for fully vaccinated adults living in urban-adjacent rural areas and between 1.42 and 1.91 for those living in nonurban-adjacent rural areas, according to the study. Compared with counties with low vaccine hesitancy, adjusted hazard ratios for breakthrough infection were 1.07 in counties with medium vaccine hesitancy and 1.33 in high vaccine-hesitant counties. The adjusted hazard ratio for breakthrough infection was 1.34 in counties with low vaccination rates compared with counties with high rates of vaccination.

However, vaccinated adults with breakthrough infection had significantly lower odds of hospitalization and adverse events regardless of where they lived, the study found.

“Unfortunately, both vaccine hesitancy and lower compliance with such precautionary measures have become so politically charged in the United States that public health messaging based solely on findings such as ours may not be as persuasive as, for example, appeals to protect the most vulnerable members of a community,” researchers wrote. “To be most effective, public health interventions in some rural communities may benefit from input from multiple stakeholders, and community leaders working together with medical providers and public health officials to develop very targeted messages.”

Reference:
Anzalone AJ, Sun J, Vinson AJ, et al. Community risks for SARS-CoV-2 infection among fully vaccinated US adults by rurality: a retrospective cohort study from the National COVID Cohort Collaborative. PLoS One. Published online January 5, 2023. doi:10.1371/journal.pone.0279968