23-valent pneumococcal vaccine shows low, moderate effectiveness in older adults

A 23-valent vaccine showed only low to moderate effectiveness in protecting older adults from pneumococcal pneumonia, researchers in Japan reported. Researchers recommended further investigation to improve the vaccine’s impact. “Although there is good evidence that PPV23 reduces the risk of invasive pneumococcal disease in older people, its protective effect against pneumonia is controversial,” Motoi Suzuki, MD, of the department of clinical medicine at the Institute of Tropical Medicine, Nagasaki University, and colleagues wrote. “To our knowledge, no study has assessed the serotype-specific effect of PPV23 against pneumococcal pneumonia.” The researchers performed a multicenter prospective study on patients with community-onset pneumonia who visited four hospitals in Japan between Sept. 28, 2011 and Aug. 23, 2014 (n = 2,036). All patients were aged 65 years or older. Suzuki and colleagues collected Streptococcus pneumoniae from sputum and blood samples, serotyping the samples using the capsular Quellung method. The researchers also tested sputum samples using PCR assays,...