Decreased relative risk of pneumococcal pneumonia during the last decade, a nested case-control study

Abstract

BackgroundStreptococcus pneumoniae (SP) is one of the most common pathogens of Community-Acquired Pneumonia (CAP), but recent reports suggest that its incidence may be declining in relation to the use of the conjugate 13-valent pneumococcal vaccine in children. We compared the result of the immunochromatographic SP urinary antigen test (SPUAT) and clinical outcomes in patients with CAP admitted in two periods of time: 2001–2002(CAP1) and 2015–2016(CAP2).MethodsThis was a matched nested case-control study of two prospectively recorded cohorts of patients admitted with CAP, with SPUAT and blood culture performed in all patients. CAP2 cases and CAP1 controls were matched for age ± 4 years, sex, and Pneumonia Severity Index (PSI) score ± 10 points. Odds ratios (OR) for having SPUAT positive was estimated by conditional logistic regression. A multivariate model assessed the contribution of individual variables.ResultsFour hundred ninety-eight patients were recruited; 307 during the CAP1 and 191 during the CAP2 periods. Comparing both periods we observed differences, in age, PSI score, and the percentage of smokers, outpatients, previously immunized with pneumococcal vaccine, and positive SPUAT. On the other hand, mortality, admission from nursing homes, pneumococcal bacteremia and hospital admission were not different. After matching, pneumonia due to SP per the SPUAT was observed in 34(23.4%) of CAP1 and in 12(8.3%) of CAP2 patients (p < 0.001), and 6/145 CAP1 vs 33/145 CAP2 patients had received pneumococcal immunization before their admission (p < 0.001). A multivariate analysis confirmed that, independent of falling into PSI class 5, having not received the pneumococcal vaccine and having not survived the episode of pneumonia, there were two factors that increased the probability of having SPUAT positive: developing pneumonia during the CAP1 period (OR = 1.23) and having pneumococcal bacteremia (OR = 2.66).ConclusionWe observed a reduction of the role of SP as pathogen, along with an increase in the number of patients who received pneumococcal immunization before admission, in 2015-2016 compared to 2001-2002. In addition, the use of conjugate 13-valent vaccine, starting in 2012 for childhood immunization, could be an additional factor contributing to these changes, as a result of early herd immunity in adults pneumonia.

Pneumococcal and Influenza Vaccination Rates and Pneumococcal Invasive Disease Rates Set Geographical and Ethnic Population Susceptibility to Serious COVID-19 Cases and Deaths

“…Adult and at-risk pneumococcal and influenza vaccination data were obtained from [ 5 ] and: Andorra [ 108 ]; Argentina [ 109 , 110 ]; Belgium [ 111 ]; Brazil [ 112 ]; Central and Eastern Europe [ 113 ]; Denmark [ 114 , 115 ]; European nations [ 85 , 116 , 117 , 118 , 119 ]; Europe and Gulf nations [ 120 ]; Germany [ 121 ]; Gulf nations [ 122 , 123 ]; Hong Kong [ 124 ]; Hungary [ 125 ]; Iceland [ 126 ]; Ireland [ 127 ]; Israel [ 128 ]; Latin America [ 129 ]; Mexico [ 130 , 131 ]; New Zealand [ 132 ]; Poland [ 133 ]; Qatar [ 134 ]; San Marino [ 135 ]; Singapore [ 136 ]; Slovenia [ 137 ]; South Africa [ 138 ]; Sweden [ 139 ]; Switzerland [ 140 , 141 , 142 ]; Taiwan [ 143 , 144 , 145 ]; Turkey [ 146 , 147 , 148 ]; and U.K. [ 149 ]. All of these data are summarized in Table 1 .…”

The Role of Streptococcus pneumoniae in Community-Acquired Pneumonia

“…The authors indicated that routine childhood PCV13 vaccination, which was initiated in 2012, may have also contributed. 18 A systematic review of studies published on CAP etiology in Asia, concluded that while S. pneumoniae was the most common cause, it was of relatively less importance than that found in western studies. 19 In contrast to this, a literature review evaluating the etiology (and antibiotic management) of CAP in Europe reported on 33 published studies that recorded pathogens and noted that the pneumococcus was the most commonly isolated pathogen and was identified in between 12.0 and 85.0% of the patients in the different regions.…”