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.

BACKGROUND 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. METHODS For this multicentre, prospective study, we enrolled all individuals aged 65 years or older with… CONTINUE READING