Association between underlying conditions, multimorbidity, and COVID-19 vaccination status of adults aged ≥80 years old in Beijing, China.

Background: Promoting coronavirus disease 2019 (COVID-19) vaccination is crucial among older adults, particularly those geriatric. This study aimed to analyze the association between chronic conditions, multimorbidity, and vaccination status in adults aged ≥80 years old to provide recommendations for vaccine-preventable diseases.

Methods: A cross-sectional study was conducted in Beijing from April 5, 2023, to May 5, 2023, including participants aged ≥80 years old who did not receive the booster COVID-19 vaccination. Data on vaccination status, COVID-19 infection history, nine underlying conditions, and disease-control status were collected via cluster sampling through door-to-door interviews and telephone surveys using questionnaires. A multiple logistic regression model adjusted for age, sex, location, COVID-19 infection history, and education level were used to analyze the association between underlying conditions and vaccination status.

Results: In total, 51,834 participants were included of whom 41,209 (76.6 %) were unvaccinated. Underlying diseases (92.3 %) and multimorbidities (65.7 %) were prevalent among the participants. Hypertension (74.6 %), cardiovascular disease (48.5 %), and diabetes (42.0 %) were the most prevalent conditions. Participants diagnosed with underlying conditions were significantly associated with being unvaccinated (Odds ratio [95 % confidential interval] OR [95 %CI]: 2.21 [2.05-2.37]). Furthermore, the proportion of unvaccinated individuals increased with both the number and severity of underlying conditions.

Conclusions: The number and severity of underlying conditions were associated with unvaccinated status. To promote vaccination for geriatrics, standardized vaccination guidelines for individuals with underlying conditions should be developed. Additionally, family doctors play an essential role in vaccination assessment and recommendations during disease diagnosis and treatment.