Conjugate Vaccine Prevents Vaccine-Type CAP in Elderly: The CAPiTA Trial

PHILADELPHIA, PA—PCV13, a 13-valent pneumococcal conjugate vaccine, had an efficacy rate of 45.56% for preventing the first episode of vaccine-type pneumococcal community-acquired pneumonia (VT-CAP) in healthy adults 65 years of age and older, results of the CAPiTA trial concluded at IDWeek 2014.

This rate was 75.0% for vaccine-type invasive pneumococcal disease (VT-IPD), said Susanne Huijts, MD, of the Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.

She said that although pneumococcal conjugate-vaccines are effective in preventing IPD and pneumonia in children, their efficacy in preventing pneumococcal pneumonia or IPD in older adults has not been investigated. This is due, in part, to lack of a specific and sensitive test for identifying causative Streptococcus pneumoniae serotypes.

Therefore, for CAPiTA (Community-Acquired Pneumonia Immunization Trial in Adults), Pfizer developed a serotype-specific urinary antigen binding assay to detect PCV13-type capsular polysaccharide in adults with pneumonia that has a 97% sensitivity and 100% specificity.

CAPiTA randomly assigned 84,496 adults 65 years of age or older to receive the PCV 13 vaccine or placebo. Excluded were those with previous pneumococcal vaccination or immune deficiency or suppression. VT-CAP, the primary endpoint, was defined as 2 or more clinical findings consistent with CAP; a chest x-ray consistent with CAP; and culture of VT S. pneumoniae from a sterile site and/or positive VT by urinary antigen detection.

Non-bacteremic/non-invasive pneumococcal (NB/NI) CAP and VT-IPD, with or without pneumonia, were the secondary endpoints. NT/NI VT pneumococcal CAP was defined as confirmed VT pneumococcal CAP by urinary antigen detection and VT-IPD by VT S. pneumoniae in sterile site.

Mean age of the patients in both the PCV13 arm (n=42,327) and the placebo arm (n=42,255) was 72.8 years; 55.5% and 56.3%, respectively, were male, and comorbidities (eg, asthma, diabetes mellitus, and heart, liver, or lung disease) were balanced between the two arms.

In the per protocol analysis, vaccine efficacy of 45.56% (95.2%, 21.82%–62.49%, P=0.0006) was demonstrated for the first episode VT-CAP; 45.00% (95.2%, 14.21%–65.31%, P=0.0067) for the first episode of NB/NI VT-CAP, and 75.00% (95.2%, 41.43%–90.78%, P=0.0005) for the first episode of VT-IPD. None of the serious adverse events or deaths were considered to be vaccine related.

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