5 Risk Factors for COVID-19 Breakthrough Infections

by Cerner’s Christy Dueck

While vaccinations are one of our most effective strategies to significantly mitigate the spread and most severe health consequences of COVID-19, they’re not 100% effective. Since last year, we’ve seen spikes in breakthrough COVID-19 cases. Data is key to helping us better understand COVID-19 and be more proactive in preventing its serious complications. The Cerner Learning Health Network^™(LHN) provides researchers with real-world, de-identified data from a nationwide network of diverse health systems.

ChristianaCare in Delaware is an LHN member. The health system did a deep analysis of breakthrough COVID-19 cases from December 2020 through October 2021. A team of researchers, led by Mia Papas, used Cerner Real-World Data^TM to study information from more than 70 health systems across the U.S. representing almost 90 million de-identified patients. The study population includes adults ages 18 or older who contracted COVID-19 after receiving at least one vaccine dose.

Here are five factors that increase a person’s risk of a COVID-19 breakthrough infection based on the ChristianaCare findings.

1. You’re middle-aged

Although elderly people are most at risk for COVID-19, people between the ages of 35-44 and 45-54 are more likely to have a breakthrough infection than those who are 75-84. Further studies are needed, but the most likely reason for this finding is many middle-aged people have children who are not yet old enough to be vaccinated.

2. You live in the northeastern or southeastern US

When filtered by ZIP code, the highest COVID-19 breakthrough rates were found in northeastern states including Michigan, Indiana, Ohio and Kentucky and southeastern states including Florida, Tennessee, Mississippi, Alabama and Georgia.

3. You live in the northeastern or southeastern US

The pandemic put a spotlight on the impact of social determinants of health. Unfortunately, there’s a lack of data examining race/ethnic disparities in the rate of breakthrough infection or in the risk of severe outcomes after breakthrough infections. The ChristianaCare study provides some much-needed information, which shows COVID-19 hospitalizations and deaths are more frequent among Hispanic, non-Hispanic Black and non-Hispanic American Indian or Alaska Native people than among non-Hispanic white people and Asians. This might be explained by higher levels of virus exposure, reduced access to care and higher rates of underlying health conditions in some underserved communities.

4. You have at least one of 34 underlying conditions

Certain underlying medical conditions can increase the risk for severe COVID-19 illness in adults. ChristinaCare researchers discovered 34 underlying conditions that put people at a greater risk of breakthrough infections.

5. You’re only partially vaccinated

The Centers for Disease Control and Prevention considers adults 18 or older to be fully vaccinated against COVID-19 two weeks after the second dose of the Moderna or Pfizer-BioNTech vaccines or two weeks after a single dose of Johnson & Johnson’s Jassen. The study data shows those who have only received one vaccine dose are more likely to experience a breakthrough infection. Although risk rises over time for fully vaccinated people, it’s at a much lower level than for those who are partially vaccinated. COVID-19 breakthrough infection rate was 4.2% for partially vaccinated individuals, and 1.2% for those who are fully vaccinated.

While the findings from the ChristianaCare study are a deep dive into the Delta variant, the healthcare community continues to analyze breakthrough infections in subsequent variants.

The Cerner Learning Health Network can help your organization accelerate the discovery, development and deployment of groundbreaking therapeutics by harnessing the power of everyday healthcare. Learn more here.

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