title: Serotype-specific effectiveness of 23-valent pneumococcal polysaccharide vaccine against pneumococcal pneumonia in adults aged 65 years or older: a multicentre, prospective, test-negative design study.
abstract: The serotype-specific effectiveness of 23-valent pneumococcal polysaccharide vaccine (PPV23) against pneumococcal pneumonia has not been established in people aged 65 years or older. We assessed the effectiveness of PPV23 in this population.
  
  
  
  For this multicentre, prospective study, we enrolled all individuals aged 65 years or older with community-onset pneumonia who visited four study hospitals in Japan between Sept 28, 2011, and Aug 23, 2014. Streptococcus pneumoniae was isolated from sputum and blood samples, and serotyped by the capsular Quellung method. Sputum samples were further tested by PCR assay to identify pneumococcal DNA, and positive samples were examined for 50 serotypes by a nanofluidic real-time PCR assay. Urine samples were tested by a urinary antigen test. Serotype-specific vaccine effectiveness was estimated using the test-negative design.
  
  
  
  2621 eligible patients visited the study hospitals, of whom 585 did not have sputum samples available and were excluded from our analysis. 419 (21%) of 2036 patients were positive for pneumococcal infection (232 by sputum culture, 317 by sputum PCR, 197 by urinary antigen test, and 14 by blood culture). 522 (26%) patients were judged to be vaccinated in the analyses. Effectiveness of PPV23 was 27·4% (95% CI 3·2 to 45·6) against all pneumococcal pneumonia, 33·5% (5·6 to 53·1) against PPV23 serotypes, and 2·0% (-78·9 to 46·3) against non-PPV23 serotypes. Although no significant differences between subgroups were seen, higher protection was noted in people younger than 75 years, women, and individuals with lobar pneumonia or health-care-associated pneumonia.
  
  
  
  PPV23 showed low to moderate effectiveness against vaccine serotype pneumococcal pneumonia in people aged 65 years or older. To improve the current pneumococcal vaccination programme, the variability of PPV23 effectiveness in different groups of older people must be further investigated.
  
  
  
  Pfizer and Nagasaki University.
authors.affiliation: Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
authors.forename: Motoi
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan.
authors.forename: Bhim Gopal
authors.initials: BG
authors.lastname: Dhoubhadel
authors.affiliation: Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ishifuji
authors.affiliation: School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Yasunami
authors.affiliation: Department of General Internal Medicine, Kameda Medical Center, Chiba, Japan.
authors.forename: Makito
authors.initials: M
authors.lastname: Yaegashi
authors.affiliation: Department of Internal Medicine, Juzenkai Hospital, Nagasaki, Japan.
authors.forename: Norichika
authors.initials: N
authors.lastname: Asoh
authors.affiliation: Department of Pulmonology, Chikamori Hospital, Kochi, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ishida
authors.affiliation: Department of General Internal Medicine, Ebetsu City Hospital, Hokkaido, Japan.
authors.forename: Sugihiro
authors.initials: S
authors.lastname: Hamaguchi
authors.affiliation: Department of Pulmonology, Kameda Medical Center, Chiba, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Aoshima
authors.affiliation: Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
authors.forename: Koya
authors.initials: K
authors.lastname: Ariyoshi
authors.affiliation: Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan. Electronic address: komorimo@nagasaki-u.ac.jp.
authors.forename: Konosuke
authors.initials: K
authors.lastname: Morimoto
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006761:Hospitals; D006801:Humans; D007564:Japan; D008297:Male; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D011018:Pneumonia, Pneumococcal / Q000188:drug therapy* / Q000382:microbiology; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction; D012703:Serotyping / Q000145:classification*; D013183:Sputum / Q000382:microbiology; D013296:Streptococcus pneumoniae / Q000276:immunology / Q000302:isolation & purification*; D014611:Vaccination / Q000379:methods
chemical_list: C414006:23-valent pneumococcal capsular polysaccharide vaccine; D022242:Pneumococcal Vaccines