Breakthrough COVID-19 infections after vaccination occurred in 7.5% of Texans surveyed, and higher odds were associated with Hispanic ethnicity, larger household size, rural versus urban living, type of vaccination, and multiple comorbidities, according to findings from UTHealth Houston School of Public Health, published Feb. 2 in the Journal of Infectious Diseases.
The data were collected from December 2020 to June 2022 through the Texas Coronavirus Antibody Response Survey (CARES), and showed that the incidence of breakthrough infections spiked as immunity likely waned and newer variants emerged. This information points to the ongoing need to monitor the longevity of immunity, either from the vaccine or from COVID-19 infection, according to the researchers.
“The arrival of new variants has likely resulted in reduced effectiveness of primary series vaccination," said Stacia DeSantis, PhD, corresponding author of the paper and professor of biostatistics and data science at UTHealth Houston School of Public Health. “If we were to analyze today's data, which is five to six months more of data, I certainly expect a higher percentage of breakthrough than we saw as of June 2022.”
Researchers examined self-reported data from 22,575 people over the age of 20 who were enrolled in the Texas CARES survey, an ongoing prospective population-based seroprevalence project designed to assess infection- and vaccine-induced antibody status over time among a volunteer population throughout Texas. Enrollment began in October 2020.
Of the 1,700 participants who self-reported breakthrough infections of the virus, 112 participants experienced severe outcomes that resulted in hospitalization. Breakthrough infections were more frequent when the Omicron variant was dominant.
Hispanic participants reported a higher incidence of breakthrough cases and severe outcomes, which mirrors what has been reported in overall COVID-19 cases in literature, and signifies the disproportionate burden of the virus in the Hispanic population.
“In raw numbers, 9.8% of Hispanic participants had a breakthrough infection versus, for example, 7.4% of non-Hispanic white participants and 8.3% of Black participants. The breakthrough percentage may seem close, but since the sample size is large, the difference is significant,” DeSantis said.
Among vaccines, researchers found that there were significantly elevated odds of breakthrough infections in those receiving Pfizer or Johnson & Johnson versus Moderna. The Johnson & Johnson vaccine was associated with the highest number of breakthrough infections.
Analysis showed that health care employees also had higher reports of breakthrough infections. “Working in health care is an obvious exposure and so are the jobs that require frequent face-to-face interactions,” DeSantis said. Comorbidities such as asthma, obesity and hypertension were identified as risk factors for a severe level of breakthrough infections, which resulted in an ER visit or hospitalization.
Additional UTHealth Houston School of Public Health authors included Eric Boerwinkle, PhD, dean; Michael D. Swartz, PhD, associate professor and vice chair of the Department of Biostatistics; Sarah E. Messiah, PhD, MPH; Harold W. Kohl, III, PhD, MSPH; and Steven H. Kelder, PhD, MPH, all professors of epidemiology, human genetics and environmental sciences; Ashraf Yaseen, PhD, assistant professor of data science; Melissa A. Valerio-Shewmaker, PhD, associate professor of health promotion and behavioral sciences; Luis León-Novelo, PhD, associate professor of biostatistics; Cesar L. Pinzon Gomez, MD, research associate; Lindsay N Padilla, MPH, research coordinator; Jessica A. Ross, BS, project manager; Yashar Talebi, MS, biostatistician, and Tianyao Hao, MS, graduate research assistant.
Other authors included David E. Lakey, MD, vice chancellor for health affairs and chief medical officer at The University of Texas System; Jennifer A. Shuford, MD, MPH, commissioner of the Texas Department of State Health Services; Stephen J. Pont, MD, MPH, medical director, Center for Public Health Policy and Practice at Texas Department of State Health Services; and Mark Silberman, MD; and Samantha Tuzo, BS, with Clinical Pathology Laboratories.
Funding for Texas CARES was provided by the Texas Department of State Health Services (HHS00086660000).
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