Serotype Distribution in Non-Bacteremic Pneumococcal Pneumonia: Association with Disease Severity and Implications for Pneumococcal Conjugate Vaccines

Abstract

BackgroundThere is limited knowledge of serotypes that cause non-bacteremic pneumococcal pneumonia (NBP). Here we report serotypes, their associated disease potential and coverage of pneumococcal conjugate vaccines (PCV) in adults with NBP and compare these to bacteremic pneumonia (BP).MethodsAdults with pneumonia and Streptococcus pneumoniae isolated from the lower respiratory tract or blood were included 1 year in a population-based design in Denmark. Pneumonia was defined as a new infiltrate on chest radiograph in combination with clinical symptoms or elevated white blood count or plasma C-reactive protein. All isolates were serotyped using type-specific pneumococcal rabbit antisera. All values are medians with interquartile ranges.ResultsThere were 272 cases of NBP and 192 cases of BP. Ninety-nine percent were hospitalized. NBP and BP cases were of comparable age and sex but NBP cases had more respiratory symptoms and less severe disease compared to BP cases. In total, 46 different serotypes were identified. Among NBP cases, 5 serotypes accounted for nearly a third of isolates. PCV10 and -13 types covered 17% (95% confidence interval (CI): 11-23%) and 34% (95% CI: 25-43%) of NBP isolates, respectively. In contrast, the five most frequent serotypes accounted for two-thirds of BP isolates. PCV10 and -13 types covered 39% (95% CI: 30-48%) and 64% (95% CI: 48-79) of BP isolates, respectively. More severe NBP disease was associated with infection with invasive serotypes while there was an inverse relationship for BP.ConclusionsOnly a third of cases of adult non-bacteremic pneumococcal pneumonia would potentially be preventable with the use of PCV13 and just one sixth of cases with the use of PCV10 indicating that PCVs with increased valency are needed to increase vaccine coverage for NBP in adults. PCV13 could potentially prevent two-thirds of adult bacteremic pneumococcal pneumonia.

Background paper to the updated pneumococcal vaccination recommendation for older adults in Germany

“…Presumably serotype distribution is influenced by herd protection through infant vaccination in a similar manner as in IPD cases. In Denmark, serotype distribution in PP cases in adults was investigated in 2011, 1 year after the switch from PCV7 to PCV13 in the infant vaccination programme [75]. In PP cases with bacteraemia (i. e. IPD cases), the proportion of PCV13 serotypes was 59 % (95 % CI, 48-70 %), and that of PPSV23 serotypes was 87 % (95 % CI, 74-100 %).…”

Resistencia antibiótica y distribución de serotipos en cepas neumocócicas invasivas en adultos hospitalizados en Lima, Perú

“…El serotipo 19A es frecuente en otras partes del mundo, como lo reportan estudios de China (135 adultos) y Dinamarca (464 adultos), pero no resultó predominante en nuestro estudio ni en los latinoamericanos en referencia (18,(24)(25)(26) . Las diferencias podrían darse por cambios temporales en la distribución de los serotipos, o por aspectos geográficos.…”

“…En estudios extranjeros se describe que la vacuna PCV13 cubre entre 64-77,9% de los serotipos invasivos y, en este estudio se halló que esta vacuna cubriría el 51,2% de los serotipos de nuestro medio (25,26,28) . La vacuna PPV23, por su parte, cubriría el 60,4% de las cepas aisladas disminuyendo ampliamente los casos y con ello la mortalidad y los gastos asociados.…”

Community-acquired pneumonia

“…1) [17], with recent data showing further benefit of the extended valency PCV-13 that protects against 13 S. pneumoniae serotypes [18 & ]. A higher proportion of bacteraemic CAP is caused by vaccine serotypes, suggesting that the vaccine may have a particular benefit in reducing the incidence of more severe cases of S. pneumoniae CAP [19,20]. However, there are in total at least 93 serotypes of S. pneumoniae and the dominant serotypes causing disease vary with geography.…”