In France, pneumococcal vaccination in adults is recommended for risk groups (chronic conditions/immunosuppression). During 2014-2018, we conducted a study in adults to identify factors associated with severe invasive pneumococcal disease (IPD).
We included nonmeningitis IPD cases from 25 acute care hospitals in 6/13 French regions. We defined severe cases as those with shock or severe sepsis or ICU admission/mechanical ventilation or those who died within 30 days of hospitalization. Infectious disease specialists collected clinical/microbiological data on cases. We calculated adjusted risk ratios (aRR) using binomial regression.
1,156 cases were diagnosed; 53% were severe; 85% had comorbidities; 20% died within 30 days of hospitalization; 8% were vaccinated against pneumococcus. Compared with previously healthy cases, the risk of severe IPD increased 16% (aRR=1.16; 95%CI=1.01-1.35), 20% (aRR=1.20; 95%CI=1.01-1.43) and 35% (aRR=1.35; 95%CI=1.11-1.65) in cases with 1 or 2 or >2 chronic diseases (excluding immunosuppression), respectively. The risk was 24% (aRR=0.76; 95%CI=0.58-0.99) lower in cases vaccinated with pneumococcal vaccines, but 30% (aRR=1.30; 95%CI=1.04-1.63) higher in those infected with serotype 3, compared with serotype 8.
The risk of severe IPD increased moderately with increasing number of comorbidities, adding evidence for future recommendations for adult pneumococcal immunization and disease prevention.