Recurrence of pneumonia in relation to the antibody response after pneumococcal vaccination in middle-aged and elderly adults.

We have recently studied the efficacy of pneumococcal vaccine in preventing pneumonia recurrences after hospital treatment for community-acquired pneumonia in non-immunocompromised patients aged 50-85 y. Among these patients, we have now compared the antibody response to the pneumococcal vaccine between patients who developed pneumonia (n = 50) and patients without pneumonia recurrences (n = 100), during a mean follow-up period of 32 months after vaccination. The antibody levels of 5 pneumococcal serotypes were measured before, and 4 weeks, 1 y and 3 y after vaccination. A lower risk of pneumonia recurrences was seen in patients with antibody fold increases (FIs) > 4 from pre-vaccination to post-vaccination compared with patients with lower FIs (p = 0.02). The results suggest that in this patient category, the antibody response to pneumococcal vaccination is of importance for the risk of pneumonia recurrence.