Abstract
BackgroundTo explore the overall prevalence and serotype distribution of nasopharyngeal carriage of Streptococcus pneumoniae(S. pneumoniae) among healthy children.MethodsA search for pneumococcal nasopharyngeal carriage studies including children published up to July 31th, 2016 was conducted to describe carriage in China. The review also describes antibiotic resistance in and serotypes of S. pneumoniae and assesses the impact of vaccination on carriage in this region. Summary measures for overall prevalence, antibiotic resistance, and serotype distributions extracted from the analyzed data were determined with 95% confidence intervals (CIs) using random-effects models. Heterogeneity was assessed using I2 test statistics.ResultsThirty-seven studies were included in this review, and the majority of studies (64.9%) were located in the pre-introduction period of 7-valent pneumococcal conjugate vaccine (PCV7) in China. The pooled prevalence of S. pneumoniae nasopharyngeal carriage was 21.4% (95% CI: 18.3–24.4%). Carriage was highest in children attending kindergartens [24.5%, (19.7–29.3%)] and decreased with increasing age. Before the introduction of PCV7 into China, the prevalence of S. pneumoniae nasopharyngeal carriage was 25.8% (20.7–30.9%), the pooled carriage of S. pneumoniae sharply dropped into the 14.1% (11.3–16.9%) by PCV7 vaccination period (P < 0.001). Before the pneumococcal conjugate vaccine (PCV) was introduced in China, the penicillin resistance rate in S. pneumoniae isolated from healthy children was 31.9% (21.2–42.6%); however, this rate sharply decreased after the introduction of PCV7 in China [21.6%, (7.4–35.9%)], and the difference between the rates during these two time periods was statistically significant (P value <0.05). Serotypes 19F, 6A and 23F were the most commonly isolated. Meta-analysis of data from young children showed a pooled rate estimate of 46.6% (38.8–54.4%) for PCV7 vaccine coverage and 66.2% (58.6–73.8%) for PCV13 vaccine coverage.ConclusionsThe prevalence of nasopharyngeal carriage among children was high in China. PCV7 immunization was found to be associated with reduction of nasopharyngeal colonization of S. pneumoniae. Conjugate vaccination coverage was slightly affected by the introduction of PCV7 into China because of low vaccination rate. The government should implement timely adjusted conjugate vaccination strategies based on our findings.
Highlights
To explore the overall prevalence and serotype distribution of nasopharyngeal carriage of Streptococcus pneumoniae(S. pneumoniae) among healthy children
Because S. pneumoniae carriage is more common than the S. pneumoniae disease, it is important to investigate carriage status to evaluate the effect of new pneumococcal vaccines [6]
When the 7-valent pneumococcal vaccine was introduced in mainland China, the invasive pneumococcal disease burden decreased sharply, especially disease caused by the vaccine type (VT) serotypes; this decrease was accompanied by an increase in non-vaccine type (NVT) serotype, serotype 19A, as previously seen in Europe [7, 8]
Summary
To explore the overall prevalence and serotype distribution of nasopharyngeal carriage of Streptococcus pneumoniae(S. pneumoniae) among healthy children. Streptococcus pneumoniae (S. pneumoniae) is a major pathogen that can cause invasive pneumococcal disease (IPD) and respiratory tract infections and result in high morbidity and mortality. The World Health Organization has reported that nearly 500,000 children under 5 years of age are infected by S. pneumoniae annually, and the vast majority of these infections occur in developing countries [1]. Asymptomatic nasopharyngeal carriage of S. pneumoniae is an essential element of the transmission of pneumococcal disease [2], a prerequisite for the occurrence of invasive pneumococcal disease, and a known risk factor for subsequent acute and recurrent otitis media [3, 4]. The prevalence of nasopharyngeal pneumococcal carriage has been found to vary in different countries and regions [5]. When the 7-valent pneumococcal vaccine was introduced in mainland China, the invasive pneumococcal disease burden decreased sharply, especially disease caused by the vaccine type (VT) serotypes; this decrease was accompanied by an increase in non-vaccine type (NVT) serotype, serotype 19A, as previously seen in Europe [7, 8]
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