Pneumococcal disease in HIV-infected patients: vaccination an unresolved issue

Abstract number: 1134_01_273

Guardiola J., Matas L., Herrera S., Mateo M., Lacal A., Corominas H., Mauri A., Montiel J., Puig M., Gurgui M., Benito S., Domingo P.

Background:  

Pneumococcal disease is preventable in HIV-infected patients but the efficacy of pneumococcal vaccine in this population remains controversial. The aim of this study was to describe the characteristics of pneumococcal disease and analyze the vaccine response in a population of HIV patients.

Methods:  

In a retrospective study of the clinical records and microbiological database we analysed the incidence of pneumococcal infection in patients visited at the HIV Unit of our hospital over a 9-year period (1996–2003). Vaccine use and immunological and virological status were assessed in all patients. The study was carried out in a universitary tertiary hospital.

Results:  

A total of 74 (4.9%) pneumococcal episodes were recorded in 65 of 1502 HIV-infected patients. Mean age was 40 + 9 years (18–79), 53 males (71.6%), 55% IDU, 39.2% were C3 and 16.3% were B2-B3 stages, and mean of HIV infection was 135 months. Baseline CD4 count was 276 cell/mm³ and viral load was 251,240 cop/ml. Streptococcus pneumoniae was isolated from respiratory specimens in 40 patients (54.1%) and 29 (39.2%) patients had pneumococcal bacteraemia. Mean CD4 during the infectious process was 289 cell/mm³ and viral load was 369,000 cop/m³. Only 35 (47.3%) patients received 23 valent pneumococcal vaccine. Mean basal CD4 count for vaccinated and no vaccinated patients were 362 and 206 cell/mm³, respectively (p < 0.04). Mean CD4 counts and HIV RNA viral loads at vaccination and 3 months after vaccination were 362 and 368 cell/mm³ and 41,791 and 72,996, respectively (p < 0.7 and 0.1). In 17/35 (57.1%) patients the episode was diagnosed after a mean of 799 (55–2582) days of vaccination. The CD4 at vaccination was 343 cell/mm³. Patients without pneumococcal episode after vaccination showed a mean CD4 of 313 (p < 0.5).

Conclusions:  

Prevalence of Streptococcus pneumoniae infections in our HIV population was 4.9%. Less than half of patients had been vaccinated, mainly due to low CD4 count. Vaccination did not significantly modify CD4 count or HIV RNA viral load. However, pneumococcal disease developed in 57% of those previously vaccinated.