P Naucler1,2, B Henriques-Normark3,4,5,6, J Hedlund1,2, I Galanis3, F Granath7, Å Örtqvist1,8. 1. From the, Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden. 2. Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden. 3. Public Health Agency of Sweden, Solna, Sweden. 4. Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden. 5. Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden. 6. SCELSE and LKC, Nanyang Technological University, NTU, Singapore, Singapore. 7. Department of Medicine Solna, Clinical Epidemiology Unit, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden. 8. Department of Communicable Disease Control and Prevention, Stockholm County Council, Stockholm, Sweden.
Abstract
BACKGROUND: There is limited evidence on the impact of pneumococcal conjugate vaccine childhood immunization programmes (PCV-CIP) on community-acquired pneumonia (CAP) in individuals with underlying diseases. METHODS: A nationwide cohort study using Swedish health registers to assess the incidence of hospitalization with all-cause (AC-CAP) and pneumococcal or lobar (PL-CAP) CAP between 2005 and 2015, in relation to PCV-CIP introduction in 2007-09. RESULTS: In total, 303 691 episodes of AC-CAP occurred, of which 14 225 were PL-CAP. Comparing before (2005-06) with after (2014-15) PCV-CIP, relative incidence reductions were 36% (95% Confidence Interval 32-40), 20% (14-25) and 16% (11-22) of AC-CAP for age groups < 2, 2-4 and 5-17 years, respectively, with similar reductions in young children with and without comorbidities. The reductions were more pronounced for PL-CAP. In the age groups 40-64, 65-74, 75-84 and ≥85 years there were relative increases of 11% (8-14), 18% (15-22), 15% (12-17) and 30% (27-34) of AC-CAP, respectively, but these increases were attenuated after adjustment for admittance practices using four control conditions. In adults with comorbidities, there was an increase in incidence of AC-CAP, and PL-CAP, in contrast to adults without reported underlying diseases where the incidence was stable or diminished for some age groups. Over the study period, there was an increased proportion of pneumonia patients with underlying diseases in all ages. CONCLUSION: This emphasizes that direct preventive interventions should be targeted towards individuals with underlying diseases. Future studies should investigate reasons for the observed increased risk in adults with comorbidities, for example due to pneumococcal nonvaccine serotypes, or other pathogens, preferentially affecting subjects with underlying diseases.
BACKGROUND: There is limited evidence on the impact of pneumococcal conjugate vaccine childhood immunization programmes (PCV-CIP) on community-acquired pneumonia (CAP) in individuals with underlying diseases. METHODS: A nationwide cohort study using Swedish health registers to assess the incidence of hospitalization with all-cause (AC-CAP) and pneumococcal or lobar (PL-CAP) CAP between 2005 and 2015, in relation to PCV-CIP introduction in 2007-09. RESULTS: In total, 303 691 episodes of AC-CAP occurred, of which 14 225 were PL-CAP. Comparing before (2005-06) with after (2014-15) PCV-CIP, relative incidence reductions were 36% (95% Confidence Interval 32-40), 20% (14-25) and 16% (11-22) of AC-CAP for age groups < 2, 2-4 and 5-17 years, respectively, with similar reductions in young children with and without comorbidities. The reductions were more pronounced for PL-CAP. In the age groups 40-64, 65-74, 75-84 and ≥85 years there were relative increases of 11% (8-14), 18% (15-22), 15% (12-17) and 30% (27-34) of AC-CAP, respectively, but these increases were attenuated after adjustment for admittance practices using four control conditions. In adults with comorbidities, there was an increase in incidence of AC-CAP, and PL-CAP, in contrast to adults without reported underlying diseases where the incidence was stable or diminished for some age groups. Over the study period, there was an increased proportion of pneumoniapatients with underlying diseases in all ages. CONCLUSION: This emphasizes that direct preventive interventions should be targeted towards individuals with underlying diseases. Future studies should investigate reasons for the observed increased risk in adults with comorbidities, for example due to pneumococcal nonvaccine serotypes, or other pathogens, preferentially affecting subjects with underlying diseases.