Impact of Prior Pneumococcal Vaccination on Clinical Outcomes in HIV-infected Adult Patients Hospitalized with Invasive Pneumococcal Disease

Background: Recent studies in hospitalized patients with community-acquired pneumonia have found a lower risk of bacteraemia and better clinical outcomes in patients who had previously received the 23-valent pneumococcal polysaccharide vaccine (PPV) in comparison with unvaccinated individuals. The aim of this study was to assess the influence of prior PPV on clinical outcomes in HIV-infected adult patients hospitalized with invasive pneumococcal disease (IPD).

Methods: This was an observational study of all consecutive HIV-infected adults hospitalized with IPD from January 1996 to October 2007 in three hospitals in Spain. Baseline characteristics and clinical outcome-related variables were compared according to prior PPV vaccination status.

Results: A total of 162 episodes of IPD were studied. In 23 of these (14.2%), patients had previously received PPV. In both vaccinated and unvaccinated patients, most of the causal serotypes were included in the 23-valent PPV (76.9% and 84.1%, respectively). Overall, 25 patients (15.4%) died during hospitalization, 21 patients (13%) required admission to an intensive care unit (ICU) and 34 patients (21%) reached the composite outcome of death and/or admission to the ICU. None of the 23 patients who had previously received PPV died or required ICU admission, in comparison with 25 (18%; P=0.026) and 21 (15.1%; P=0.046), respectively, of the unvaccinated patients. The length of hospital stay for vaccinated patients was significantly shorter (8.48 vs. 13.27 days; P=0.011).

Conclusions: Although 23-valent PPV failed to prevent IPD in some HIV-infected patients, vaccination produced beneficial effects on clinical outcomes by decreasing illness severity and mortality related to IPD.