Ensuring full COVID-19 vaccination series completion is vital in the fight against the pandemic. A recent study conducted among Kaiser Permanente patients in Southern California analyzed risk factors associated with not completing the two-dose primary series of mRNA COVID-19 vaccines. The study, using data from December 2020 through June 2022, observed that 3.3 percent of 2.5 million vaccine recipients failed to complete the series within six months.
Stanley Xu, PhD, Kaiser Permanents Bernard J. Tyson School of Medicine (KPSOM) Associate Professor of Health Systems Science, and Bruno Lewin, MD, Assistant Professor of Clinical Science, are coauthors of the article, “Risk Factors for Not Completing a 2-Dose Primary Series of Messenger RNA COVID-19 Vaccination in a Large Health Care System in Southern California: Retrospective Cohort Study,” recently published in the journal JMIR Public Health and Surveillance.
The study highlights significant factors influencing completion rates. Patients aged 45 to 64 were more likely to not complete the series, while those aged 25 to 44, 65 to 74, and over 75 showed higher completion rates. Male individuals faced a greater risk of noncompletion, whereas Hispanic and non-Hispanic Black individuals had a lower risk. Having Medicaid, prior influenza vaccination, SARS-CoV-2 infection, adverse events, and inpatient or emergency department visits during the recommended intervals were associated with higher noncompletion rates.