Direct Effect of 10-Valent Conjugate Pneumococcal Vaccination on Pneumococcal Carriage in Children Brazil

Article (PDF Available)inPLoS ONE 9(6):e98128 · June 2014with69 Reads
DOI: 10.1371/journal.pone.0098128 · Source: PubMed
Abstract
Background 10-valent conjugate pneumococcal vaccine/PCV10 was introduced in the Brazilian National Immunization Program along the year of 2010. We assessed the direct effectiveness of PCV10 vaccination in preventing nasopharyngeal/NP pneumococcal carriage in infants. Methods A cross-sectional population-based household survey was conducted in Goiania Brazil, from December/2010-February/2011 targeting children aged 7–11 m and 15–18 m. Participants were selected using a systematic sampling. NP swabs, demographic data, and vaccination status were collected from 1,287 children during home visits. Main outcome and exposure of interest were PCV10 vaccine-type carriage and dosing schedules (3p+0, 2p+0, and one catch-up dose), respectively. Pneumococcal carriage was defined by a positive culture and serotyping was performed by Quellung reaction. Rate ratio/RR was calculated as the ratio between the prevalence of vaccine-types carriage in children exposed to different schedules and unvaccinated for PCV10. Adjusted RR was estimated using Poisson regression. PCV10 effectiveness/VE on vaccine-type carriage was calculated as 1-RR*100. Results The prevalence of pneumococcal carriage was 41.0% (95%CI: 38.4–43.7). Serotypes covered by PCV10 and PCV13 were 35.2% and 53.0%, respectively. Vaccine serotypes 6B (11.6%), 23F (7.8%), 14 (6.8%), and 19F (6.6%) were the most frequently observed. After adjusted for confounders, children who had received 2p+0 or 3p+0 dosing schedule presented a significant reduction in pneumococcal vaccine-type carriage, with PCV10 VE equal to 35.9% (95%CI: 4.2–57.1; p = 0.030) and 44.0% (95%CI: 14.–63.5; p = 0.008), respectively, when compared with unvaccinated children. For children who received one catch-up dose, no significant VE was detected (p = 0.905). Conclusion PCV10 was associated with high protection against vaccine-type carriage with 2p+0 and 3p+0 doses for children vaccinated before the second semester of life. The continuous evaluation of carriage serotypes distribution is likely to be useful for evaluating the long-term effectiveness and impact of pneumococcal vaccination on serotypes reduction.

Figures

Full-text (PDF)

Available from: Ruth Minamisava, Dec 23, 2014
    • "The low number of serotypes tested and the difference in origin between serotypes are limitations to the in vitro part of this study. The carriage prevalence found in this study is lower than observed previously in Norway (Steens et al., 2015), and more similar to what has been seen in other developed countries (Van Hoek et al., 2014; Desai et al., 2015; Andrade et al., 2014). The methods used for swab collection, transport and incubation in enrichment broth and culturing were unchanged from former studies, indicating a real difference in carriage prevalence that may have resulted from vaccination. "
    [Show abstract] [Hide abstract] ABSTRACT: Background As a standard method for pneumococcal carriage studies, the World Health Organization recommends nasopharyngeal swabs be transported and stored at cool temperatures in a medium containing skim-milk, tryptone, glucose and glycerol (STGG). An enrichment broth used for transport at room temperature in three carriage studies performed in Norway may have a higher sensitivity than STGG. We therefore compared the media in vitro and in vivo . Methods For the in vitro component, three strains (serotype 4, 19F and 3) were suspended in STGG and enrichment broth. Recovery was compared using latex agglutination, quantification of bacterial loads by real-time PCR of the lytA gene, and counting colonies from incubated plates. For the in vivo comparison, paired swabs were obtained from 100 children and transported in STGG at cool temperatures or in enrichment broth at room temperature. Carriage was identified by latex agglutination and confirmed by Quellung reaction. Results In vitro , the cycle threshold values obtained by PCR did not differ between the two media ( p = 0.853) and no clear difference in colony counts was apparent after incubation ( p = 0.593). In vivo , pneumococci were recovered in 46% of swabs transported in STGG and 51% of those transported in enrichment broth (Kappa statistic 0.90, p = 0.063). Discussion Overall, no statistical differences in sensitivity were found between STGG and enrichment broth. Nevertheless, some serotype differences were observed and STGG appeared slightly less sensitive than enrichment broth for detection of nasopharyngeal carriage of pneumococci by culturing. We recommend the continued use of STGG for transport and storage of nasopharyngeal swabs in pneumococcal carriage studies for the benefit of comparability between studies and settings, including more resource-limited settings.
    Full-text · Article · Sep 2016
    • "Use of secondary data such as hospitalization databases may bias the results, for instance due to misclassification or changes in coding practices [52]. A conservative approach using internal controls (e.g., comparison with an unrelated disease rate) was used in some studies to limit biases [17,22,28]. However, this approach may prevent comparisons between studies and may offset a net impact on disease [28]. "
    [Show abstract] [Hide abstract] ABSTRACT: Brazil introduced the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV, Synflorix™, GSK Vaccines) in the routine childhood immunization program in 2010 with a 3+1 schedule (with catch-up for children <2 years-old). This review represents the first analysis of the overall impact of a second-generation pneumococcal conjugate vaccine on nasopharyngeal carriage and all the major pneumococcal disease manifestations in a single, pneumococcal conjugate vaccine-naïve, developing country. A total of 15 published articles and 13 congress abstracts were included in the analysis. In children <5 years-old, studies showed a positive impact of PHiD-CV on the incidence of vaccine-type and any-type invasive pneumococcal disease (including decreases in pneumococcal meningitis morbidity and mortality), on pneumonia incidence and mortality, and on otitis media. Nasopharyngeal carriage of vaccine-type and any-type pneumococci decreased after the primary doses, with no early signs of replacement with other pathogens. Finally, herd protection against vaccine-type invasive pneumococcal disease and pneumonia in unvaccinated subjects was shown in some studies for some age groups. In conclusion, pneumococcal disease decreased after the introduction of PHiD-CV into the Brazilian national immunization program. Further follow-up is needed to evaluate the long-term overall impact of PHiD-CV in the Brazilian population.
    Full-text · Article · Apr 2016
    • "As compared to the unvaccinated, this Impact of PCV for Older Children: A Systematic Review group had a rate ratio of 0.820 (95% CI 0.556–1.210), which was not significant [30] . A crosssectional analysis from Kenya found a 0.47 (95% CI 0.21–1.03) "
    [Show abstract] [Hide abstract] ABSTRACT: Pneumococcal conjugate vaccine (PCV) is included in the World Health Organization’s routine immunization schedule and is recommended by WHO for vaccination in high-risk children up to 60 months. However, many countries do not recommend vaccination in older age groups, nor have donors committed to supporting extended age group vaccination. To better inform decision-making, this systematic review examines the direct impact of extended age group vaccination in children over 12 months in low and middle income countries.
    Full-text · Article · Sep 2015
Show more