Effect of Pneumococcal Conjugate Vaccination in Uruguay, a Middle-Income Country

Abstract

BackgroundIn 2008, a 7-valent pneumococcal conjugate vaccine (PCV7) was introduced into the routine childhood immunization program in Uruguay, with a 2+1 schedule. In 2010, PCV13 replaced PCV7, and the same 2+1 schedule was used. The effect of these pneumococcal vaccines on the incidence of invasive pneumococcal infections (IPD) and on serotype distribution was analyzed retrospectively, based on passive national laboratory surveillance.MethodsData from 1,887 IPD isolates from 5 years before and 5 years after PCV7 introduction (7 before and 3 after PCV13 introduction) was examined to assess the incidence rate per 100,000 age-specific population of all IPD, PCV7-serotypes, and PCV13-serotypes associated IPD among children <2 years and 2 to 4 years old, and patients ≥5 years old. Trends of frequency for each serotype were also analyzed.ResultsComparison of pre-vaccination (2003–2007) and post-vaccination (2008–2012) periods showed a significant decrease in IPD incidence among children <2 years old (IR 68.7 to IR 29.6, p<0.001) and children 2 to 4 years (p<0.04). IPD caused by serotypes in PCV7 was reduced by 95.6% and IPD caused by 6 serotypes added in PCV13 was reduced by 83.9% in children <5 years old. Indirect effects of both conjugate vaccines were observed among patients ≥5 years old one year after the introduction of each vaccine, in 2010 for PCV7 and in 2012 for PCV13. Nevertheless, for reasons that still need to be explained, perhaps due to ascertainment bias, total IPD in this group increased after 2007. In 2012, the relative frequency of vaccine serotypes among vaccinated and unvaccinated population declined, except for serotype 3. Non vaccine serotypes with increasing frequency were identified, in rank order: 12F, 8, 24F, 22F, 24A, 15C, 9N, 10A and 33.ConclusionConsecutive immunization with PCV7 and PCV13 has significantly reduced IPD in children <5 years of age in Uruguay.

Impact and Effectiveness of 10 and 13-Valent Pneumococcal Conjugate Vaccines on Hospitalization and Mortality in Children Aged Less than 5 Years in Latin American Countries: A Systematic Review

“…Disregarding the outlier estimate by Andrade et al [32], VE varied from 34.7% to 66.0%. Effectiveness was even higher for vaccine-types IPD, as reported by Domingues et al [15] in a case-control study in Brazil, and Garcia Gabarrot et al [44] in a before-after study in Uruguay (Table 4; Fig 4). Results from Domingues et al [15] were corroborated by Verani et al [16], based on the same study but with an indirect cohort design, which reported an adjusted VE of an age-appropriate PCV-10 schedule against type-specific pneumococcal IPD of 73.9% (95%CI 41.9%-88.3%), and 72.8% (95%CI 44.1%-86.7%), respectively, for children with up-to-date schedule, and one or more PCV doses.…”

“…Serotype 19A cases decreased from 13 to 8. Similarly, in Uruguay [44], important reductions of serotype specific IPD cases were reported after PCV-13 introduction in children aged < 5 years, for serotype 14, and serotype 5. Small decreases were observed for the other PCV-13 serogroups, except for serogroup 3 and 4, which showed modest increase, and 19A, which did not change substantially.…”

“…Four studies addressed invasive pneumococcal disease (IPD) hospitalizations [15, 32, 44, 45], none of which analyzed IPD mortality. Reported baseline IPD rates ranged from 3.9 (predicted rates based on time-series modelling for children aged 2–4 years) to 68.7 (children <2 years old in Uruguay) per 100,000 children (Table 4).…”

Pneumococcal serotype distribution: A snapshot of recent data in pediatric and adult populations around the world

“…The latter 2 age groups overlap because otherwise would have required omitting 2 studies. 5,6 The results are tabulated by geographic region and disease type (IPD or non-IPD) in reverse chronological order (newest to oldest). Of specific interest for the purposes of this article is the prevalence of non-PCV serotypes; prevalence data for PCV7, PCV10 and PCV13 serotypes are grouped, and non-PCV-serotype prevalence data are provided by serotype as available.…”

“…There were 9 studies reporting serotype distribution data among adults aged 65 y and older with IPD 5,6,18,24,[55][56][57][58][59] and another 3 with similar data on non-IPD conditions (Table 2). [60][61][62] Conjugate vaccine serotypes (i.e., serotypes included in PCV13) causing IPD among older adults were highly prevalent (> 60% of serotypes) in only 2 studies, one Polish 6 and one Spanish.…”