Impact of pneumococcal conjugate vaccine (PCV7 and PCV13) on pneumococcal invasive diseases in Italian children and insight into evolution of pneumococcal population structure.

The use of PCV7 for children immunization was gradually implemented in the Italian regions starting from 2006 and was replaced by PCV13 in 2010-2011. In this study we aimed to assess the PCV impact on invasive pneumococcal diseases (IPD) incidence, serotype distribution and antibiotic resistance in Italian children under 5years old. All IPD cases in children from 5 Italian regions (Emilia-Romagna, Lombardia, A. P. Bolzano, A. P. Trento, and Piemonte) reported through the nationwide surveillance system during 2008-2014 were included in this study. Pneumococcal isolates were subjected to serotyping, antibiotic susceptibility testing, and clonal analysis according to standard methods. During the study period overall IPD incidence decreased from 7.8 cases/100,000 inhabitants in 2008 to 3.0 cases/100,000 in 2014 (61% decrease, P<0.001). In particular, from 2008 to 2014, PCV7-type IPD decreased from 2.92 to 0.13 cases/100,000 inhabitants (95% decrease, P<0.001) while PCV13-non-PCV7 type IPD decreased from 3.2 to 0.89 cases/100,000 inhabitants (72% decrease, P=0.008). Conversely, non-vaccine serotype (NVS) IPD increased overtime, becoming more common than PCV13 serotype IPD in 2013-2014. Emergent NVS 24F and 12F were the most prevalent in 2014. Antibiotic resistance testing revealed an overall increasing trend in penicillin resistance, from 14% in 2008 to 23% in 2014. Erythromycin resistance showed a downward trend, from 38% in 2008 to 27% in 2014. While in 2008 PCV13 serotypes were the major responsible for antibiotic resistance, during the following years antimicrobial resistance due to NVS increased, mainly as a result of expansion of pre-existing clones. Both PCVs led to a substantial decrease in vaccine-related IPD incidence in the children population. However NVS-related IPD increased, becoming the most prevalent in the last two-years period. Continuous surveillance is an essential tool to monitor evolution of pneumococcal population causing IPD in children.

Camilli R ，D'Ambrosio F ，Del Grosso M ，Pimentel de Araujo F ，Caporali MG ，Del Manso M ，Gherardi G ，D'Ancona F ，Pantosti A ，Pneumococcal Surveillance Group ... -  《-》

Impact of the pneumococcal conjugate vaccines on invasive pneumococcal disease in France, 2001-2012.

Vaccination with the 7-valent pneumococcal conjugate vaccine (PCV7) was recommended in France in 2003 for children <2 years. The 13-valent conjugate vaccine (PCV13) replaced PCV7 in 2010. We assessed the impact of PCVs vaccination on the incidence of invasive pneumococcal diseases (IPD) in French children (0-15 years) and adults (>15 years). IPD rates were calculated using cases reported from 2001 to 2012 to Epibac, a laboratory network. The distribution of serotypes was assessed from invasive isolates serotyped at the National reference Centre for Pneumococci. IPD incidence rates were compared between the pre-PCV7 (2001-2002), late PCV7 (2008-2009) and post PCV13 (2012) periods. The PCVs coverage increased from 56% in the 2004 birth-cohort to 94% in the 2008 and following birth-cohorts. Following PCV7 introduction, IPD incidence decreased by 19% between 2001-2002 and 2008-2009 in children <2 years, but increased in children aged 2-15 years and adults, despite a sharp decline in PCV7-IPD in all age-groups. After PCV13 introduction, IPD incidence decreased by 34% in children <5 years, by 50% in those aged 5-15 years and 15% in adults from 2008-2009 to 2012. The incidence of PCV13-Non PCV7-IPD decreased by 74% in children <5 years and by 60% in those aged 5-15 years. Vaccination with PCV13 was rapidly followed by a decrease in the incidence of all-type IPD in children, in relation with a sharp decrease in the incidence of PCV13-Non PCV7-IPD. Moreover, all-type IPD decreased after PCV13 introduction in older non-vaccinated age-groups, with a shift in the distribution of serotypes. Considering the whole 2001-2012 period, the vaccination with PCV7 and PCV13 resulted in a decline in the incidence of IPD in children up to the age of 5 but not in older children and adults.

Lepoutre A ，Varon E ，Georges S ，Dorléans F ，Janoir C ，Gutmann L ，Lévy-Bruhl D ，Microbiologists of Epibac ，ORP Networks ... -  《-》

Long-term Impact of a "3 + 0" Schedule for 7- and 13-Valent Pneumococcal Conjugate Vaccines on Invasive Pneumococcal Disease in Australia, 2002-2014.

Australia introduced universal 7-valent pneumococcal conjugate vaccine (PCV7) from 2005, replaced by 13-valent PCV (PCV13) in 2011, uniquely among high-income countries giving doses at 2, 4, and 6 months (3 + 0 schedule). Data on impact of a timely 3 + 0 PCV schedule with high coverage are sparse, with none for PCV13. We used national surveillance of invasive pneumococcal disease (IPD) from 2002 for baseline and appropriate later comparison periods to calculate incidence rate ratios (IRRs) by serotype and age using a Poisson model. PCV coverage was assessed from the Australian Childhood Immunisation Register. After 9 years of timely 3-dose PCV coverage of >92%, all-age IPD in Australia almost halved (IRR, 0.53; 95% confidence interval [CI], .50-.57), but differed by PCV era. Reductions in IPD due to vaccine serotypes from PCV7 (IRR, 0.20; CI, .17-.22) were about 2-fold greater than for IPD due to extra serotypes in PCV13 (13v-non7v) in a similar period (IRR, 0.58; CI, .51-.66). Post-PCV13 declines in serotype 19A IPD in persons aged <2 years (IRR, 0.23; CI, .13-.35) and ≥2 years (IRR, 0.35; CI, .28-.44) differed from other 13v-non7v IPD (IRR, 0.73; CI, .35-1.48 for those aged <2 years and IRR, 0.96; CI, .81-1.15 for those ≥2 years). Meningitis due to vaccine serotypes nearly disappeared in children eligible for 3 PCV13 doses. IPD due to non-PCV13 serotypes increased by 30% compared with 76% for non-PCV7 serotypes in equivalent period of vaccine use. Reductions in vaccine-type IPD post-PCV13 were inferior to Australian experience with PCV7 and reports from high-income countries giving a PCV booster dose. Applicability of findings to other settings would depend on age of IPD onset, serotype profile, and timeliness of vaccination.

Jayasinghe S ，Menzies R ，Chiu C ，Toms C ，Blyth CC ，Krause V ，McIntyre P ... -  《-》

Nationwide population-based surveillance of invasive pneumococcal disease in Japanese children: Effects of the seven-valent pneumococcal conjugate vaccine.

In Japan, the seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2010. PCV13 has replaced PCV7 since November 2013. The effectiveness of PCV7 in protecting against invasive pneumococcal disease (IPD) in children aged <5 years was evaluated in a nationwide active population-based surveillance of IPD in 2008-2013 in 10 prefectures in Japan. 1181 cases were identified; 711 pneumococcal strains were analyzed for serotyping and antimicrobial resistance. Compared with the baseline IPD incidence (25.0 per 100,000), a 98% decline in IPD caused by PCV7 serotypes was found after the introduction of PCV7. This was partially offset by an increased incidence of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes, resulting in a 57% decline in overall IPD incidence. Absolute increases in the incidence rates of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes were 2.1 and 2.8 per 100,000 during the study period, respectively. The proportion of meropenem-nonsusceptible strains, especially with serotypes 19A and 15A, increased significantly after PCV7 introduction. Our data confirmed a 98% decline in IPD incidence caused by PCV7 serotypes in children aged <5 years and serotype replacement after PCV7 introduction. This shows the importance of continuing surveillance of serotypes responsible for IPD and their antimicrobial resistance in Japan.

Suga S ，Chang B ，Asada K ，Akeda H ，Nishi J ，Okada K ，Wakiguchi H ，Maeda A ，Oda M ，Ishiwada N ，Saitoh A ，Oishi T ，Hosoya M ，Togashi T ，Oishi K ，Ihara T ... -  《-》

Incidence of invasive pneumococcal disease before and during an era of use of three different pneumococcal conjugate vaccines in Quebec.

In Quebec, 7-valent (PCV7), 10-valent (PCV10) and 13-valent (PCV13) pneumococcal conjugate vaccines were successively used for the immunization of children according to a 2+1 doses schedule. Our aim was to assess the impact of this program on the epidemiology of invasive pneumococcal disease (IPD) in children and adults. Notification and laboratory surveillance data were analyzed and the immunization status of IPD cases in children was checked. In children < 5 years, the IPD rate decreased from 69/100,000 in 2003 to 12/100,000 in 2016 (83% reduction). Following PCV7 introduction in 2004, there has been a rapid decline in PCV7-type IPD cases and 6A. 7F and 19A serotypes emerged but their incidence decreased following PCV10 introduction in 2009 and PCV13 in 2011, whereas decrease in serotype 3 IPD was modest. Non-PCV13 types increased and represented 79% of cases in 2016. The same pattern was seen in adults but replacement was complete and there was no decrease in overall IPD rate. In those 65 years and over, PCV13 serotypes represented 28% of cases in 2016 and 62% were serotypes included in the 23-valent polysaccharide vaccine. Out of 10 IPD cases caused by serotype 3 in children vaccinated with PCV13 in 2011-2016, 6 occurred more than one year following the booster dose, which suggests short-term protection. Out of 31 breakthrough 19A cases, 19 occurred in children aged between 8 and 14 months who had received the 2 primary PCV13 doses but not the toddler booster dose, which suggests a window of susceptibility in a 2+1 schedule. PCVs had a major impact on the IPD rate in children but not in adults. Among elderly adults, the proportion of cases caused by serotypes included in PCV13 is diminishing year after year but a majority of cases remains covered by the 23-valent polysaccharide vaccine.

De Wals P ，Lefebvre B ，Deceuninck G ，Longtin J ... -  《-》