Nasopharyngeal carriage of Streptococcus pneumoniae among children in an urban setting in Brazil prior to PCV10 introduction

Abstract

Information on pneumococcal carriage in the pre-vaccine period is essential to predict and assess the impact of PCV in settings where disease surveillance is particularly difficult. Therefore, we present data on pneumococcal carriage before the introduction of the 10-valent-pneumococcal conjugate vaccine (PCV10) in Brazil. We conducted a prospective study on a cohort of 203 children aged < 5 years-old, randomly selected in an urban community located in the periphery of the city of Salvador, Brazil and followed them from January/2008 to January/2009. Nasopharyngeal swabs were collected from each child at four times. In total, 721 swabs were collected, yielding a pneumococcal carriage prevalence of 55% (n=398). In multivariate analyses, the variables associated with carriage were having contact with three or more children <2 years old (OR, 2.00; 95% CI 1.33–2.89) and living in a house with an average of 3 residents per room (OR, 1.77; 95% CI 1.05–3.10). Also, white participants were more likely to be protected from colonization (OR, 0.52; 95% CI 0.29–0.93), and prevalence of carriage varied over time, with lower prevalence occurring from February to June (OR, 0.53; 95% CI 0.37–0.78) compared to July to January. Contact with children under two years of age and living in crowded housing also were associated with colonization by highly invasive serotypes, although this relationship was not significant. The most prevalent vaccine serotypes were 6A/B (25.4%), 19F (10.1%) and 14 (9.0%), while the most prevalent non-vaccine serotypes were 16F (4.8%), 15B/C (4.5%) and 6C/D (3.5%). Overall, 38.4% (153/398) of the isolates were non-susceptible to penicillin, and of those, 73.8% (113/153) were non-susceptible to trimethoprim/sulfamethoxazole. Colonization rate by PCV10 serotypes was 52.2%. Routine PCV10 vaccination can lead to significant changes in pneumococcal serotypes found in NP colonization, indicating a need for continued monitoring, especially in crowded settings, as occurs in Brazil’s slums.

Nasopharyngeal Carriage of Streptococcus pneumoniae and Associated Factors among Children in Southwest Ethiopia

“…The nasopharyngeal carriage rate of 25.3% in the current study is higher than a study conducted in Japan, 22% [27]. Whereas, the result is in harmony with a study carried out in India, 27.9% [28] and far lower than studies done in Brazil, 55% [29], Gambia,58.6% [30], Uganda, 33% [31], Ghana, 48.9% [32], Nigeria, 52.5% [33], and Kenya, 51% [34]. Compared to previous studies in Ethiopia, the result is lower as compared to studies conducted in Gondar, 41.03% [22], and Jimma, 43.8% [23].…”

“…Age was found as a significantly associated factor for the nasopharyngeal carriage rate of Streptococcus pneumoniae. A similar study from Brazil documented children under 2 years of age group to be associated with pneumococcal colonization [29]. In addition, a study from India indicated the progressive decrease in the carriage rate with the increasing age of the children [28].…”

Pneumococcal Colonization in the Familial Context and Implications for Anti-Pneumococcal Immunization in Adults: Results from the BINOCOLO Project in Sicily

“…Pneumococcal carriage was inversely related to the number of rooms in the house but directly related to household size, thus suggesting that such factors might play an important role in sustaining the overall circulation of pneumococcal strains at the family-level. These findings were in accordance with Menezes et al [ 34 ], who recently described the same pathway among children in an urban community characterized by crowded environments in the households.…”

Dynamics of Colonization of Streptococcus pneumoniae Strains in Healthy Peruvian Children

“…Studies assessing overall carriage rather than new acquisitions have reported lower carriage rates than those estimated from our cohort. A study of Brazilian children under 5 years old reported a 4-month risk of carriage of 74% prior to PCV introduction [ 27 ], equivalent to a yearly rate of 4.09 detections [ 28 ] and substantially lower than our estimated rates for both before and after PCV introduction. Similarly, studies from Bangladesh [ 29 ] and Thailand-Myanmar [ 11 ] of PCV-naïve populations report a 2-month colonization risk of approximately 50% in newborns, also equivalent to a yearly rate of slightly more than 4 detections.…”