A new study reveals that COVID-19 vaccines outperform natural immunity in reducing hospitalizations, emergency visits, and deaths across all age groups.
Vaccinated individuals, especially those over 60, had notably better outcomes. The research suggests vaccines offer stronger protection against severe disease, even though vaccinated people were more likely to contract COVID.
Real-World Comparison of COVID-19 Vaccines vs. Natural Immunity
In one of the first large-scale, real-world studies comparing COVID-19 vaccines to natural immunity, researchers from Regenstrief Institute, Indiana University School of Medicine, and Vanderbilt University Medical Center found that vaccination provided significantly better protection against death, hospitalizations, and emergency department (ED) visits for any reason, including COVID, than natural immunity from a prior infection. This benefit was seen across all age groups, with particularly impressive results for adults aged 60 and older.
Vaccinated individuals had a 37% lower risk of death and hospitalizations for any cause compared to those relying on natural immunity. Additionally, their rate of ED visits was 24% lower than for those previously infected with COVID.
Vaccination Outperforms Natural Immunity in Severe Disease Prevention
“This large population study of the entire state of Indiana should encourage individuals everywhere to get themselves and their children vaccinated and not rely on natural immunity. While the incidence of COVID infection was higher in vaccine recipients (6.7 percent) than in individuals previously infected (2.9 percent), the vaccine protected against severe disease while natural immunity did not confer the same benefit,” said study corresponding author and Regenstrief Institute Vice President for Data and Analytics Shaun Grannis, M.D. “As vaccinated individuals were more likely to actually get COVID than those with natural immunity, the lower death rate of vaccine recipients who develop COVID appears to be due to vaccination and not to a tendency for risk-averse behaviors, such as mask-wearing, hand sanitizing, and social distancing.”
Data on pairs of vaccine recipients and individuals with prior infections, aged between 12 and 110 years, matched on age, sex, CDC-defined COVID risk scores, and dates of initial exposure (to the vaccines or the virus itself) were compared. This information was extracted from the Indiana Network for Patient Care, one of the nation’s largest health information exchanges. Death reports from the State of Indiana were also analyzed.
Implications for Public Health and Vaccine Efficacy
“This study has important public health implications as previous studies investigated COVID-specific ED visits, hospitalizations, and mortality but didn’t capture the non-COVID related ones,” said study first author Regenstrief Institute Research Scientist Wanzhu Tu, Ph.D. “Our work confirms that mRNA vaccines have kept people out of the ED and the hospital as well as lowered the likelihood of death from any cause. And we saw this pattern in every age group.”
The study concludes, “The significantly lower rates of all-cause ED visits, hospitalization, and mortality in the vaccinated highlight the real-world benefits of vaccination. The data raises questions about the wisdom of reliance on natural immunity when safe and effective vaccines are available.”
Reference: “SARS-CoV-2 Infection, Hospitalization, and Death in Vaccinated and Infected Individuals by Age Groups in Indiana, 2021‒2022” by Wanzhu Tu PhD, Pengyue Zhang PhD, Anna Roberts MS, Katie S. Allen BS, Jennifer Williams MPH, Peter Embi MD and Shaun Grannis MD, MS, 14 December 2022, American Journal of Public Health.
DOI: 10.2105/AJPH.2022.307112
In addition to Drs. Grannis and Tu, authors are Pengyue Zhang, PhD, IU School of Medicine; Anna Roberts, M.S. and Katie S. Allen, B.S., Regenstrief Institute; Jennifer Williams, MPH, formerly with Regenstrief Institute; and Peter Embi, former Regenstrief Institute president and CEO, currently at Vanderbilt University Medical Center.
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