Clinical effectiveness of inﬂuenza vaccination in patients
with rheumatoid arthritis
and Yueh-Han HSU
Division of Allergy, Immunology, and Rheumatology, Department of Internal Medicine, Ditmanson Medical Foundation Chiayi
Christian Hospital, Chiayi City,
Management Ofﬁce for Health Data, China Medical University Hospital,
College of Medicine,
China Medical University,
Healthcare Service Research Center, Taichung Veterans General Hospital, Taichung,
Population Health Sciences, National Health Research Institutes, Miaoli County,
Department of Family Medicine, Min-Sheng
General Hospital, Taoyuan,
Department of Medical Research, China Medical University Hospital, China Medical University,
Department of Internal Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi City, and
Department of Nursing, Min-Hwei College of Health Care Management, Tainan City, Taiwan
Objective: To determine the clinical effectiveness of inﬂuenza vaccination in patients with rheumatoid arthritis
Methods: The present study was conducted by using the Taiwan National Health Insurance Research Database.
In this retrospective nationwide study, we included 3748 RA patients who received inﬂuenza vaccinations in
2008, 2009 and 2010, and 3748 matched RA patients who did not receive inﬂuenza vaccinations. We followed
the patients from 4 weeks after inﬂuenza vaccination to the end of the inﬂuenza season in each year. After
adjustment for potential confounding factors, including disease-modifying anti-rheumatic drugs, we used the
Cox proportional hazards regression model to analyze the clinical effectiveness of inﬂuenza vaccination.
Results: The inﬂuenza vaccination rate in RA patients was 14.8% in 2008, 19.8% in 2009 and 9.50% in 2010.
Receiving inﬂuenza vaccine was associated with reduced risk of hospitalization for septicemia, bacteremia or vir-
emia (hazards ratio [HR] = 0.65, 95% CI = 0.45–0.94), and lower risk of mortality (HR = 0.62, 95%
CI = 0.39–0.97). The effectiveness was particularly signiﬁcant in elderly patients.
Conclusions: RA patients receiving inﬂuenza vaccine have signiﬁcantly lower morbidity and mortality, particu-
larly in elderly patients. Further studies are needed to explore effective policies to increase the vaccination rate in
elderly RA patients.
Key words: autoimmune disease, disease-modifying anti-rheumatic drugs, effectiveness, inﬂuenza vaccination,
Rheumatoid arthritis (RA) is the most common form of
inﬂammatory arthritis and also a major cause of global
In Taiwan, the prevalence and incidence of
RA is 101.6 per 100 000 persons and 17.2 per 100 000
person-years, respectively, both of which are the highest
among autoimmune diseases.
Patients with RA are at
increased risk of developing infections compared with
non-RA subjects, with the respiratory tract being one of
the most vulnerable sites of infection.
and comorbidities, including chronic lung disease,
organic brain disease and diabetes mellitus, increase the
Correspondence: Yueh-Han Hsu, Department of Internal Medi-
cine, Ditmanson Medical Foundation Chia-Yi Christian
Hospital, 539 Zhong-Xiao Road, Chia-Yi City, Taiwan. Email:
© 2018 Asia Paciﬁc League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd
International Journal of Rheumatic Diseases 2018; 21: 1246–1253