Decreasing incidence and changes in serotype distribution of invasive pneumococcal disease in persons aged under 18 years since introduction of 10-valent and 13-valent conjugate vaccines in Portugal, July 2008 to June 2012

Abstract

The 10-valent pneumococcal conjugate vaccine (PCV10) became available in Portugal in mid-2009 and the 13-valent vaccine (PCV13) in early 2010. The incidence of invasive pneumococcal disease (IPD) in patients aged under 18 years decreased from 8.19 cases per 100,000 in 2008-09 to 4.52/100,000 in 2011-12. However, IPD incidence due to the serotypes included in the 7-valent conjugate vaccine (PCV7) in children aged under two years remained constant. This fall resulted from significant decreases in the number of cases due to: (i) the additional serotypes included in PCV10 and PCV13 (1, 5, 7F; from 37.6% to 20.6%), particularly serotype 1 in older children; and (ii) the additional serotypes included in PCV13 (3, 6A, 19A; from 31.6% to 16.2%), particularly serotype 19A in younger children. The decrease in serotype 19A before vaccination indicates that it was not triggered by PCV13 administration. The decrease of serotype 1 in all groups, concomitant with the introduction of PCV10, is also unlikely to have been triggered by vaccination, although PCVs may have intensified and supported these trends. PCV13 serotypes remain major causes of IPD, accounting for 63.2% of isolates recovered in Portugal in 2011-12, highlighting the potential role of enhanced vaccination in reducing paediatric IPD in Portugal.

Estimation of the invasive disease potential of Streptococcus pneumoniae in children by the use of direct capsular typing in clinical specimens

“…As shown in other publications, temporal changes in serotypes were detected throughout the study period [23,24]. We observed a reduction of serotypes 1 and 7FA, as well as an increase of serotypes 3 and 6A.…”

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

“…Despite the availability of PCV, among the 21 studies assessing IPD among children, serotypes included in PCV accounted for >60% of the total serotypes in 11 reports. 6,11,12,14,[16][17][18][19][20][21][22] Serotype 19A was among the most commonly identified in all of the geographic regions included in this review. In addition, serotypes 1 and 14 were prominent in Europe and Latin America and serotypes 6B, 14 and 19F were important in Africa-East Mediterranean, demonstrating geographic variations in the prevalence of PCV serotypes among pediatric IPD cases.…”

“…Two studies from Spain contained both IPD and non-IPD data (Table 1). 17,20 Conjugate vaccine serotypes (i.e., serotypes included in PCV13) causing IPD among children were highly prevalent (> 60% of serotypes) in 11 reports, 6,11,12,14,16-22 including 6 of 7 European studies, 6,[16][17][18][19][20] while the highest prevalence from North American studies was 46%. 25 In contrast, conjugate vaccine serotypes causing non-IPD conditions among children were more than 50% prevalent in only 5 of 30 studies (Table 1).…”

Doença Invasiva Pneumocócica Pediátrica Antes da Vacinação Universal: 1995 - 2015

“…Os serotipos mais frequentemente isolados estão contidos na VCP13v (75,5%; 37/49), destacando-se o 3 e 19A, correspondentes também a serotipos frequentemente isolados em Portugal. 9 O pequeno número de serotipos disponí-veis não permitiu analisar a sua evolução e a distribuição por grupos etários afetados. Fenoll A et al analisaram as tendências seculares (1990 -2013) dos serotipos na era pré e pós-vacinal em regiões de Espanha sem vacinação universal.…”