title: Prospective cohort study on the effectiveness of influenza and pneumococcal vaccines in preventing pneumonia development and hospitalization.
abstract: Pneumonia and acute exacerbation of chronic illness are leading causes of influenza-related hospitalization. Therefore, influenza and pneumococcal vaccinations are strongly recommended for adults with comorbidities. Using a hospital-based influenza surveillance system, we performed a multicenter, prospective cohort study of patients visiting emergency rooms with influenza-like illness (ILI) during the influenza epidemic period in 2013 to 2014. Patients aged ≥ 19 years were enrolled, and clinical data were collected. Multivariate analyses were performed to estimate the effectiveness of influenza and pneumococcal vaccination in preventing pneumonia development and hospitalization. During study periods, 2,262 patients with ILI were registered. Among 2,217 patients with available vaccination records, 31.9% (707 patients) and 9.7% (216 patients) had received influenza and pneumococcal vaccines, respectively. Among patients who had been administered a pneumococcal vaccine, 94.4% had received the 23-valent polysaccharide vaccine (PPV23). The adjusted rates of effectiveness of the influenza vaccine for preventing pneumonia development and hospitalization were 64.0% (95% confidence interval [CI] = 29% to 81%) and 35.0% (95% CI = 12% to 52%), respectively. Pneumococcal vaccination did not reduce pneumonia development or hospitalization. In conclusion, influenza rather than PPV23 vaccination may reduce pneumonia development and hospitalization in patients with preceding ILI.
authors.affiliation: Department of Internal Medicine, Korea University College of Medicine, Seoul, Republic of Korea Transgovernmental Enterprise for Pandemic Influenza in Korea (TEPIK), Seoul, Republic of Korea.
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Song
authors.affiliation: Inha University School of Medicine, Incheon, Republic of Korea.
authors.forename: Jin Soo
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Catholic University Medical College, St. Vincent's Hospital, Suwon, Republic of Korea.
authors.forename: Seong-Heon
authors.initials: SH
authors.lastname: Wie
authors.affiliation: Yonsei University, Wonju College of Medicine, Wonju, Republic of Korea.
authors.forename: Hyo Youl
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Hallym University College of Medicine, Chuncheon, Republic of Korea.
authors.forename: Jacob
authors.initials: J
authors.lastname: Lee
authors.affiliation: Hallym University College of Medicine, Chuncheon, Republic of Korea.
authors.forename: Yu Bin
authors.initials: YB
authors.lastname: Seo
authors.affiliation: Chungbuk National University College of Medicine, Cheongju, Republic of Korea.
authors.forename: Hye Won
authors.initials: HW
authors.lastname: Jeong
authors.affiliation: Kyungpook National University School of Medicine, Daegu, Republic of Korea.
authors.forename: Shin Woo
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Pusan National University School of Medicine, Pusan, Republic of Korea.
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Chonnam National University Medical School, Gwangju, Republic of Korea.
authors.forename: Kyung-Hwa
authors.initials: KH
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Korea University College of Medicine, Seoul, Republic of Korea Transgovernmental Enterprise for Pandemic Influenza in Korea (TEPIK), Seoul, Republic of Korea.
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Noh
authors.affiliation: Department of Internal Medicine, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Won Suk
authors.initials: WS
authors.lastname: Choi
authors.affiliation: Department of Internal Medicine, Korea University College of Medicine, Seoul, Republic of Korea Transgovernmental Enterprise for Pandemic Influenza in Korea (TEPIK), Seoul, Republic of Korea.
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Cheong
authors.affiliation: Department of Internal Medicine, Korea University College of Medicine, Seoul, Republic of Korea Transgovernmental Enterprise for Pandemic Influenza in Korea (TEPIK), Seoul, Republic of Korea wjkim@korea.ac.kr.
authors.forename: Woo Joo
authors.initials: WJ
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006760:Hospitalization / Q000639:trends*; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D011014:Pneumonia / Q000453:epidemiology / Q000517:prevention & control*; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines; D022242:Pneumococcal Vaccines