Efficacy of 23-valent pneumococcal polysaccharide vaccine in nursinghome residents- A double blind, randomized and placebo controlled trial -

INTERVENTION: Intervention type:VACCINE. Intervention1:23‐valent pneumococcal polysaccharide vaccine, Dose form:INJECTION, Route of administration:INTRAMUSCULAR, intended dose regimen:0.5 ml of the study vaccine given once with a follow‐up period of 3 years. Control intervention1:Placebo (sodium chloride), Dose form:INJECTION, Route of administration:INTRAMUSCULAR, Intended dose regimen:0.5 ml placebo (saline) given once with a follow‐up period of 3 years. CONDITION: Pneumococcal pneumonia in nursinghome residents PRIMARY OUTCOME: 1. Clinical endpoints:; 1) Incidence of pneumonia; 2) Incidence of pneumococcal pneumonia; ; 2. Safety endpoints; The type, severity, duration and frequency of adverse events and adverse drug reactions reported during the period from the first administration of study vaccine (Day 0) to the end of follow up period.; ; 3.Immunological end points; Antibody titers against 23 valent pneumococcal vaccine at 2 months and the end of follow up period after each vaccination.. Timepoint:See 'Other Information' section.. SECONDARY OUTCOME: 1) Incidence of influenzavirus ; 2) Incidence of pneumonia recurrence ; 3) Incidence of hospital admission from pneumonia overall ; 4) Incidence of hospital admission from all causes ; 5) Incidence of death from pneumonia overall ; 6) Incidence of death from all causes. Timepoint: See 'Other Information' section.. INCLUSION CRITERIA: 1.Japanese nursinghome residents 2.Signed informed consent from the patient or atorney. 3. The patient or atorney is able to comply with the study protocol for the duration of the study; available to undergo physical examinations as required by the protocol; and able to report on their health conditions such as symptoms.