Theoretical pneumococcal vaccine coverage: analysis of serotypes isolated from inpatients at a tertiary care hospital

OBJECTIVE: To evaluate Streptococcus pneumoniae serotypes isolated from an inpatient population at a tertiary care hospital, in order to determine the theoretical coverage of the 13-valent pneumococcal conjugate vaccine (PCV13) and the 23-valent pneumococcal polysaccharide vaccine (PPV23). METHODS: This was a cross-sectional study involving 118 inpatients at the Hospital São Lucas, in the city of Porto Alegre, Brazil, whose cultures of blood, cerebrospinal fluid, or other sterile body fluid specimens, collected between January 2005 and December 2016, yielded pneumococcal isolates. The theoretical vaccine coverage was studied in relation to the serotypes identified in the sample and their relationship with those contained in the pneumococcal vaccines available in Brazil. RESULTS: The majority of the population was male (n = 66; 55.9%), with a median age of 57 years (interquartile range: 33-72 years). The most common manifestation was pneumonia, and the pneumococcus was most commonly isolated from blood cultures. More than one fourth of the study population had some degree of immunosuppression (n = 34; 28.8%). Of the total sample, 39 patients (33.1%) died. There were no significant associations between mortality and comorbidity type, ICU admission, or need for mechanical ventilation. The theoretical vaccine coverage of PPV23 alone and PCV13 plus PPV23 was 31.4% and 50.8%, respectively. CONCLUSIONS: If the patients in this sample had been previously vaccinated with PCV13 plus PPV23, theoretically, 50.8% of the cases of invasive pneumococcal disease that required hospital admission could potentially have been prevented. Invasive pneumococcal disease should be prevented by vaccination not only of children and the elderly but also of adults in their economically productive years, so as to reduce the socioeconomic costs, morbidity, and mortality still associated with the disease, especially in underdeveloped countries.