Annual Incidence Of Invasive Pneumococcal Disease Research Articles

Invasive pneumococcal disease among the elderly in the later era of paediatric pneumococcal conjugate vaccination-A longitudinal study over 10 years based on public surveillance data in the Nordics.

Pneumococcal conjugate vaccines (PCVs) have proven effective in preventing both non-invasive and invasive pneumococcal disease (IPD) in small children and in older age groups. However, long-term observations and country comparisons of IPD incidence in the elderly following introduction of PCVs in paediatric national immunisation programmes (NIPs) are scarce. We aimed to estimate and compare incidence of IPD in the elderly in Denmark, Finland, Norway, and Sweden over a 10-year time span. During the study period Denmark and Norway used PCV13 in their paediatric NIP, Sweden both PCV10 and PCV13 and Finland used PCV10. Uptake of pneumococcal vaccines for the elderly was low. We collected longitudinal data on confirmed IPD cases and their serotypes among elderly people (aged ≥65 years) 2010-2019 in the four countries of interest. Annual IPD incidence rates were calculated per country, by vaccine-associated serotypes (PCV10, PCV13, PCV15, PCV20 and PPV23) and for non-vaccine serotypes. A regression model was used to estimate average annual change in incidence in each country. Incidence rates of IPD in the elderly in 2019 ranged from 31.4 to 41.8 per 100,000 people across the countries. Denmark and Norway showed an annual average decline in IPD incidence (-3.3; 95% CI: -5.6 to -1.1; p<0.01) and (-3.3; 95% CI: -5.5 to -1.0; p<0.01) respectively from 2010 to 2019, whereas no change was seen for Sweden (-0.5; 95% CI: -1.9 to 0.8; p = 0.39) or Finland (0.9; 95% CI: -1.0 to 2.7; p = 0.32). IPD incidence due to emerging serotypes, e.g., serotypes 8 and 12F, has increased. Serotype 19A remained a major cause of IPD in countries with PCV10 in paediatric NIPs. Despite paediatric PCV programmes, a considerable vaccine preventable IPD burden remains in the elderly. Further, choice of PCV in paediatric programs was associated with differences in serotype distribution and incidence amongst the elderly. Direct vaccination of the elderly with recently approved broad coverage PCVs holds promise for meaningful impact on disease burden with PCV20 covering a majority of IPD amongst the elderly in the four studied countries. Effectiveness of new vaccines in real-life clinical practice should be followed.

Invasive Pneumococcal Disease in Latvia in PCV10 Vaccination Era, 2012-2018.

In 2010 in Latvia, invasive pneumococcal disease (IPD) became a cause for concern and vaccination of infants with four doses of 7–valent pneumococcal conjugate vaccine (PCV7) commenced. In 2012, 10–valent pneumococcal conjugate vaccine (PCV10) (three doses at 2, 4, and 12–15 month of age) vaccination was introduced. We described incidence and serotype distribution of IPD in Latvia and investigated serotypes associated with death from IPD based on surveillance data. Adult vaccination against pneumococcal infection is not included in the national immunization program. Laboratory confirmed IPD cases are passively notified to the Center for Disease Prevention and Control of Latvia (CDPC) by laboratories and clinicians. We calculated incidence by age, sex, case fatality, and trend in serotypes by conducting a retrospective population-based cross-sectional study based on national IPD surveillance data. From 2012 to 2018 466 cases of IPD were reported. The highest notified incidence was in 2015 at 4.4/100,000, which fell to 3.9 in 2018. The highest mean annual IPD incidence was in infants (4.8) and in the elderly (6.0). PCV10 vaccine serotypes were the most prevalent in IPD cases up to 2015 with a decreasing trend from 50% (20/40) in 2012 to 19% (14/74) in 2018 (chi2 test for trend of odds = 0.000). PCV23nonPCV13 vaccine serotypes had an increasing trend and rose from 18% (7/40) to 34% (25/74) (chi2 test for trend of odds = 0.000). Non-Vaccine serotypes had an increasing trend and rose from 13% (5/40) to 27% (20/74) (chi2 test for trend of odds = 0.038). Reported total case fatality was 19% (87/466). The highest, at 36% (20/56), was reported in 2013. After adjusting for age, Streptococcus pneumoniae serotype 3 was associated with death from IPD (adjusted OR 2.3 95%CI 1.25–4.12 p 0.007). Surveillance data indicate evidence of serotype replacement with an increasing trend of serotype 19A and PPV23nonPCV13 and Non-Vaccine serotypes. Serotype 3 and age were associated with fatal IPD outcome. Further studies of S. pneumoniae carriage would be useful in providing more evidence to characterize serotypes' circulation.

Impact of pneumococcal conjugate vaccine on invasive pneumococcal disease in children under 5 years of age in the Czech Republic.

IntroductionThe aim of this study is to analyse the impact of vaccination of infants with pneumococcal conjugate vaccine (PCV) on the incidence of invasive pneumococcal disease (IPD) in children under 5 years of age in the Czech Republic.Material and methodsThe present study includes all IPD cases reported in children aged 0–4 years within the surveillance program in 2007–2017. The impact of PCV is analysed for five categories of IPD: cases caused by all serotypes, cases caused by PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F), cases caused by three additional PCV10 serotypes (1, 5, and 7F), cases caused by three additional PCV13 serotypes (3, 6A, and 19A), and cases caused by non-PCV serotypes. To assess the impact of PCV, the study period was divided into the pre-vaccination period 2007–2008 and post-vaccination period 2009–2017, which was divided into three three-year parts: 2009–2011, 2012–2014, and 2015–2017. Analysis of differences between periods was based on the Poisson regression model where the population numbers were handled as an offset.ResultsThe annual incidence of IPD in children under 5 years of age caused by all serotypes has had a downward trend since 2007: it dropped from 8.52/100 000 in 2007 to 2.67/100 000 in 2017, with slight increases in 2010 and 2013. All three post-vaccination periods show significantly lower (p<0.001) incidences in comparison to the pre-vaccination period, but they do not statistically significantly differ from each other.ConclusionsIPD surveillance data in the Czech Republic show that after the introduction of PCV vaccination of infants, there has been a significant decrease in the IPD incidence of children under 5 years of age. Continued IPD surveillance is essential to monitor for possible post-vaccination serotype replacement.

Incidence of invasive pneumococcal disease after introduction of the 13-valent conjugate pneumococcal vaccine in British Columbia: A retrospective cohort study.

A significant reduction in invasive pneumococcal disease (IPD) has been reported, across all ages, following the implementation of 7-valent conjugate pneumococcal vaccine (PCV7) globally, as part of infant immunization programs. We explored the additional impact of PCV13 on IPD over a 14-year period. Using provincial laboratory surveillance and hospitalization data (N = 5791), we calculated the annual incidence of IPD following the implementation of PCV13 vaccine. Poisson regression was used to evaluate changes in the overall incidence of IPD, and serotype-specific IPD between PCV7 (2004-10) and PCV13 (2011-2015) eras. Overall, IPD rates have seen a modest decline in the PCV13 compared to the PCV7 era (IRR 0.84; 95% CI: 0.79-0.89); this was seen in children ≤2 years of age, and the majority of the adult cohort. Rates of vaccine-type IPD (PCV7 and PCV13) also decreased in the PCV13 era. In contrast, IPD incidence related to non-PCV13 (IRR: 1.56; 95%CI:1.43-1.72) and non-vaccine serotypes (IRR: 2.12; 95%CI:1.84-2.45) increased in the PCV13 era compared to the PCV7 era. A modest reduction in IPD from the PCV13 vaccine was observed, with gains limited to the immunized cohort and adults. However, a significant increase in non-vaccine serotypes emphasizes the need for continued surveillance.

Invasive Pneumococcal Disease in People With Human Immunodeficiency Virus in England, 1999–2017

The 7-valent and 13-valent pneumococcal conjugate vaccines (PCVs) were introduced into the UK childhood immunization program in 2006 and 2010, respectively, with high effectiveness and resulting in both direct and indirect protection. We describe the epidemiology of invasive pneumococcal disease (IPD) in adults with human immunodeficiency virus (HIV) in England following the introduction of both PCVs. Data on a national cohort of people with HIV were linked to confirmed IPD cases in adults aged ≥ 15 years during 1999-2017. Date of HIV infection was estimated using a CD4 slope decline algorithm. Among 133 994 adults with HIV, 1453 developed IPD during 1999-2017, with 70% (1016/1453) developing IPD ≥ 3 months after their HIV diagnosis. IPD and HIV were codiagnosed within 90 days in 345 (24%) individuals. A missed opportunity for earlier HIV diagnosis was identified in 6% (89/1453), mostly in earlier years. IPD incidence in people with HIV increased from 147/100 000 in 1999 to 284/100 000 in 2007 before declining and stabilizing between 92 and 113/100 000 during 2014-2017. Mean annual IPD incidence was lower among those receiving antiretroviral therapy during 2014-17 (68 vs 720/100 000; incidence rate ratio [IRR] 9.3; 95% confidence interval [CI], 7.3-11.8; P < .001) and was markedly lower in those with a suppressed viral load (50 vs 523/100 000; IRR 10.4; 95% CI, 7.6-14.1; P < .001). The latter group still had 4.5-fold higher (95% CI, 3.8-5.3; P < .001) IPD incidence compared to the general population (11.2/100 000). IPD incidence among people with HIV reduced after PCV13 introduction and has remained stable. Adults presenting with IPD should continue to be tested for HIV infection.

Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Invasive Pneumococcal Disease After Introduction Into Routine Pediatric Use.

BackgroundIn 2010, the 13-valent pneumococcal conjugate vaccine (PCV13) replaced 7-valent PCV (PCV7) for protection against invasive pneumococcal disease (IPD). This study used laboratory surveillance data to examine the effect of PCV13 on IPD before and after PCV13 introduction among children aged 6 weeks to <6 years and those aged ≥6 weeks.MethodsObservational laboratory-based IPD surveillance data were compared for the periods May 2010–April 2018 and May 2008–April 2010 (the PCV7 period) using a database of Kaiser Permanente Northern California (KPNC) members with laboratory-confirmed IPD.ResultsAmong children aged 6 weeks to 6 years, overall IPD incidence decreased from 11.57 per 100 000 during the PCV7 period to 4.09 per 100 000 after PCV13 introduction; PCV13-type IPD incidence decreased from 5.12 to 0.84 per 100 000. Non-PCV13−serotype IPD did not change significantly in this age group (PCV7 period, 1.71 per 100 000 and after PCV13, 2.52 per 100 000). Of cases occurring in this group, bacteremia was the most common clinical diagnosis. Across all ages, IPD decreased from 9.49 to 6.23 per 100 000 and PCV13-type IPD decreased from 4.67 to 1.89 per 100 000, changes being mostly due to decreases in serotypes 19A and 7F. IPD caused by non-PCV13 serotypes did not change (3.34 and 3.35 per 100 000). Overall, pneumococci isolated after PCV13 introduction had increased susceptibility to penicillin, cefotaxime, and ceftriaxone.This prospective, laboratory-based surveillance study in Kaiser Permanente Northern California members examined annual IPD incidence before and after PCV13 introduction. In children aged 6 weeks to <6 years, IPD caused by PCV13 serotypes decreased significantly (84%) during the surveillance period.ConclusionsIPD incidence decreased further in every age group after PCV13 introduction, suggesting both direct vaccination effects in the infant population and indirect effects in adults. Clinical Trials RegistrationNCT01128439.

The shifting epidemiology and serotype distribution of invasive pneumococcal disease in Ontario, Canada, 2007-2017.

BackgroundOntario, Canada introduced a publicly-funded 13-valent pneumococcal conjugate vaccine (PCV13) for infants in 2010, replacing the 10-valent (PCV10, 2009–2010) and the 7-valent (PCV7, 2005–2009) conjugate vaccine programs; a 23-valent pneumococcal polysaccharide vaccine (PPV23) has been available for older adults since 1996. We examined the epidemiology and serotype distribution of invasive pneumococcal disease (IPD) in Ontario in the context of provincial immunization programs.MethodsWe included confirmed IPD cases reported in Ontario between 2007 and 2017. We grouped serotypes according to Ontario’s current immunization program (PCV13, PPV23, and non-vaccine-preventable) and calculated incidence rates (per 100,000 population) using population data.ResultsBetween 2007 and 2017, annual incidence of IPD in Ontario ranged between 7.3 and 9.7/100,000 per year. Measures of illness severity were high throughout the period of surveillance. After PCV13 program implementation in 2010, incidence due to PCV13 serotypes decreased significantly across all age groups, with the greatest reductions in children <5 years and adults ≥65 years. Conversely, incidence due to PPV23 unique serotypes increased significantly between 2007 and 2017, with the greatest increases observed in adults 50–64 years (1.4 to 3.5/100,000) and ≥65 years (2.3 to 7.2/100,000). Similar increases were observed in incidence due to non-vaccine-preventable serotypes among all age groups, except infants <1 year. Within specific serotypes, incidence due to serotypes 3 (0.42 to 0.98/100,000) and 22F (0.31 to 0.72/100,000) increased significantly between 2007 and 2017, while incidence due to serotypes 19A and 7F decreased significantly during the PCV13 period (2010–2017).ConclusionsEight years after PCV13 implementation in Ontario, our data suggest both direct and indirect effects on serotype-specific incidence in young children and older adults. However, overall provincial rates have remained unchanged, and IPD continues to be a severe burden on the population. The rising incidence of IPD due to PPV23 unique and non-vaccine-preventable serotypes, and the growing burden of serotypes 3 and 22F, require further study.

Invasive pneumococcal disease in Latvia seven years after PCV10 introduction

Abstract Background In 2009 in Latvia, invasive pneumococcal disease (IPD) became notifiable for physicians and in 2010 vaccination of infants with PCV7 commenced. In 2012 PCV10 vaccination was introduced. The objectives of our study were to evaluate trend of incidence and trend serotype distribution of IPD in Latvia and to investigate factors associated with death from IPD. Methods Laboratory confirmed IPD cases are passively notified to the Centre for Disease Prevention and Control of Latvia by laboratories and clinicians. We calculated incidence by age, sex, case fatality and trend in serotypes. Results From 2012 to 2018, 466 cases of IPD were reported, mean annual incidence 3.4/100,000. The notified incidence remained stable from 2012-2014 (2.7), peaked in 2015 (4.4) and fell to 3.9 in 2018. The highest mean annual IPD incidence was in infants (4.8) and in elderly (6). The highest mean annual incidence was reported in males (4.5) in comparison to females (2.4) (IR-1.8 95%CI 1.6-2.4). Case fatality was 19% (87/466) and 23% (37/162) in cases aged &amp;gt; =65 years. 90% (421/466) of isolates were serotyped. The proportion of PCV10 vaccine serotypes fell from 50% (20/40) in 2012 to 19% (14/74) in 2018 (chi2 test for trend =0.000). Since year 2017, PPV23nonPCV13 and Non-vaccine serotypes become more common. We detected PCV13 serotype (RR 2.04 95%CI 1.37-3.02), S.pneumoniae serotype 3 (RR 1. 91 95% CI 1.25-2.93) significantly associated with IPD death. Conclusions Surveillance data indicate evidence of serotype replacement. Surveillance evaluation should asses the representativeness of notification. Furthermore S. pneumoniae carriage study may be useful to characterise serotype circulation. Serotype 3 and age demonstrate independent and significant association with fatal IPD outcome. Key messages IPD surveillance data analysis indicated evidence of serotype replacement with PPV23nonPCV13, NonVaccine serotypes. Serotype 19A becomes more common with significant increasing trend. Serotype 3 and age independently and significantly associated with fatal IPD outcome. S.pneumoniae carriage study would be very useful providing more evidence of characterizing serotypes circulation.

Invasive Pneumococcal Disease in People with HIV in England, 1999-2017

Background: The 7-valent and 13-valent pneumococcal conjugate vaccines (PCVs) were introduced into the United Kingdom childhood immunisation programme in 2006 and 2010 respectively, with high effectiveness and resulting in both direct and indirect protection. We describe the epidemiology of invasive pneumococcal disease (IPD) in adults with HIV in England following the introduction of both PCVs. Methods: Data on a national cohort of people with HIV were linked to confirmed IPD cases in adults aged ≥15 years during 1999-2017. Date of HIV infection was estimated using a CD4 slope decline algorithm. Findings: Among 133,994 adults with HIV, 1,453 developed IPD during 1999-2017, with 70% (1,016/1,453) developing IPD ≥3 months after their HIV diagnosis. IPD and HIV were co-diagnosed within 90 days in 345 (24%) individuals. A missed opportunity for earlier HIV diagnosis was identified in 6% (89/1,453), mostly in earlier years. IPD incidence in people with HIV increased from 147/100,000 in 1999 to 284/100,000 in 2007 before declining and stabilising between 92-113/100,000 during 2014-2017. Mean annual IPD incidence was lower among those receiving ART during 2014-17 (720 vs. 68/100,000; IRR 9.3; 95%CI, 7.3-11.8; P<0.001) and was markedly lower in those with a suppressed viral load (523 vs. 50/100,000; IRR 10.4; 95%CI, 7.6-14.1; P<0.001). The latter group still had 4.5-fold higher (95%CI, 3.8-5.3; P<0.001) IPD incidence compared to the general population (11.2/100,000). Interpretation: IPD incidence among people with HIV reduced after PCV13 introduction and has remained stable. Adults presenting with IPD should continue to be tested for HIV infection. Funding Statement: The authors are employed by PHE. There was no additional funding for this study. Declaration of Interests: PDK, ZAC, SEC, CS, NF and VCD declare no conflicts of interest. SNL performs contract research on behalf of St. George’s University of London (SGUL) and Public Health England (PHE) for vaccine manufacturers but receives no personal remuneration. The Immunisation Department has provided vaccine manufacturers with post-marketing surveillance reports on pneumococcal and meningococcal infection which the companies are required to submit to the UK Licensing authority in compliance with their Risk Management Strategy. A cost recovery charge is made for these reports. Ethics Approval Statement: PHE has legal permission, provided by Regulation 3 of The Health Service (Control of Patient Information) Regulations 2002, to process patient confidential information for national surveillance of communicable diseases (http://www.legislation.gov.uk/uksi/2002/1438/regulation/3/made). This includes PHE’s responsibility to monitor the safety and effectiveness of vaccines.

Invasive Pneumococcal Disease in Children in Tonga.

In Tonga, pneumococcal conjugate vaccine is not a scheduled immunization. We identified all children in Tonga with invasive pneumococcal disease from 2010 to 2013. The average annual invasive pneumococcal disease incidence rate was 113/100,000 (<2 years), 50/100,000 (<5 years) and 25/100,000 (<15 years). The case fatality rate (<5 years) was 25%. The incidence rate and high case fatality rate indicate the need for pneumococcal conjugate vaccine.

Value Added by the Prevnar 13 Childhood Immunization Program in Alberta, Canada (2010-2015).

BackgroundStreptococcus pneumoniae is a pathogen causing acute respiratory infections, as well as meningitis and bacteremia. The province of Alberta, Canada, began vaccinating infants against seven S. pneumoniae serotypes in 2002 using Prevnar 7 (PCV7). However, a 13-valent conjugate vaccine (PCV13) was introduced in 2010 to address changes in the distribution of serotypes causing disease. PCV13 targets 13 serotypes including six additional serotypes to the previously adopted PCV7.ObjectiveIn this study, we estimate the impact of the new PCV13 immunization program on the burden of disease and related healthcare costs in Alberta.MethodsSerotype-specific passive surveillance invasive pneumococcal disease (IPD) data were drawn from the Alberta Public Health Laboratory. These data were used to estimate average annual IPD incidence of the six additional serotypes included in PCV13 during the PCV7 era (2000–2009), and after the introduction of PCV13 (2011–2015). The difference in estimated cases pre-/post-PCV13 was used to estimate associated changes in direct health service costs.ResultsFollowing the replacement of PCV7 with PCV13 in 2010, the number of cases of IPD caused by the additional serotypes contained in PCV13 has declined significantly across all ages. The expected number of IPD cases prevented annually is an estimated 1.6 per 100,000. Direct health service costs are expected to be averted as a result of the implementation of PCV13 universal vaccination in Alberta. Indirect benefits are experienced by ages >20 years as IPD incidence significantly declines following the PCV13 infant immunization in Alberta.ConclusionThe impact on direct healthcare costs of replacing PCV7 with PCV13 in Alberta’s public immunization program are estimated to be CAN$3.5 million as of 2015.

Reduction of Invasive Pneumococcal Disease 3 Years After the Introduction of the 13-Valent Conjugate Vaccine in the Oxfordshire Region of England

The 7-valent pneumococcal conjugate (PCV7) vaccine's impact on invasive pneumococcal disease (IPD) is well described, but few reports exist on the additional impact of the 13-valent vaccine (PCV13). We calculated the IPD incidence across all ages in a surveillance project following implementation of PCV7 (in September 2006) and PCV13 (in April 2010) in children aged <2 years (11 hospitals; 4935 cases). The overall incidence decreased from 10 cases/100 000 persons per year in 1996-1997 to 8 cases/100 000 persons per year in 2007-2008 and 7 cases/100 000 in 2012-2013. Declines were greater in children aged <2 years (from 37 cases/100 000 in 1996-1997 to 29 and 14 cases/100 000 in 2007-2008 and 2012-2013, respectively). The incidence of IPD due to PCV7 serotypes decreased in all ages after PCV7 introduction (P < .001), whereas the incidence of IPD due to the additional 6 serotypes in PCV13 and to nonvaccine types (NVTs) increased in children aged ≥2 years (P < .001 for both comparisons). The incidence of IPD due to the 6 additional serotypes in PCV13 declined significantly after PCV13 introduction in all ages (P ≤ .01), and the incidence of IPD due to NVTs declined significantly in children aged ≥2 years (P = .003). In 2011-2013, the overall incidences of IPD due to PCV7 serotypes, the 6 additional serotypes in PCV13, and NVTs were 0.3, 2.8, and 4.4 cases/100 000; the incidences among children aged <2 years were 0.9, 2.4, and 10.8 cases/100 000, respectively. The annual incidence of IPD due to vaccine serotypes (1-3 cases/100 000) among children aged <2 years and nontarget groups demonstrates the success of PCV7 and PCV13. A substantially higher incidence of IPD due to NVTs indicates the importance of ongoing surveillance and extension of vaccine polyvalency.

Initial Effects of the National PCV7 Childhood Immunization Program on Adult Invasive Pneumococcal Disease in Israel

BackgroundPCV7 was introduced as universal childhood vaccination in Israel in July 2009 and PCV13 in November 2010. Here we report data on adult invasive pneumococcal disease (IPD), two years post PCV7 implementation and before an expected effect of PCV13.MethodsAn ongoing nationwide active-surveillance (all 27 laboratories performing blood cultures in Israel), providing all blood & CSF S. pneumoniae isolates from persons >18 y was initiated in July 2009. Capture-recapture method assured reporting of >95% cases. All isolates were serotyped in one central laboratory. IPD outcome and medical history were recorded in 90%. Second year post PCV implementation is compared to the first year.ResultsDuring July 2009 to June 2011, 970 IPD cases were reported (annual incidence [/100,000] of 9.17 and 10.16 in the two consecutive years, respectively). Respective case fatality rates (CFRs) were 20% and 19.1%. Incidence of IPD and CFR increased with age and number of comorbidities. Incidence rate was significantly greater during the second winter, 7.79/100,000 vs. 6.14/100,000 in first winter, p = 0.004, with a non-significant decrease during summer months (3.02 to 2.48/100,000). The proportion of IPD cases due to PCV7-serotypes decreased from 27.5% to 13.1% (first to second year) (p<0.001). Yet, non-PCV13-strains increased from 32.7% to 40.2% (p = 0.017). The increase in non-PCV13-strains was highly significant in immunocompromised patients and to a lesser degree in non-immunocompromised at risk or in older patients (>64 y). Among younger/healthier patients serotype 5 was the major increasing serotype. Penicillin and ceftriaxone resistance decreased significantly in the second year.ConclusionsWhile overall annual incidence of IPD did not change, the indirect effect of PCV7 vaccination was evident by the significant decrease in PCV7 serotypes across all age groups. Increase in non-VT13 strains was significant in immunocompromised patients. A longer follow-up is required to appreciate the full effect of infant vaccination on annual IPD.

The status of invasive pneumococcal disease among children younger than 5 years of age in north-west Lombardy, Italy

BackgroundStreptococcus pneumoniae is a leading cause of invasive infection in young children causing morbidity and mortality. Active surveillance systems of invasive pneumococcal disease (IPD) are recommended worldwide. The aim of this study was to estimate the current incidence of IPD and to describe the serotype distribution and the antimocrobial susceptibility of S. pneumoniae isolates in children aged less than 5 years residing in North-West Lombardy, Italy.MethodsA twelve-month prospective active surveillance system recruited all children aged less than 5 years admitted for suspicion of IPD at emergency room of ten hospitals located in the monitored area. Blood samples were taken in all participants for confirmation of IPD based on isolation of S. pneumoniae from blood. Pneumococcal meningitis and sepsis were additionally confirmed by cerebrospinal fluid analysis. Serotyping and antimicrobial susceptibility testing were performed on isolates from blood.ResultsA total of 15 confirmed cases of IPD were detected among 135 recruited children, including pneumonia (n = 8), bacteremia (n = 4), sepsis (n = 2) and meningitis (n = 1). The annual IPD incidence rate was 50.0/100,000 (95%CI, 30.5-82.5/100,000). Incidence was 58.3/100,000 (28.8-120.1/100,000) among children aged less than 2 years and 44.4/100,000 (22.9-87.5/100,000) among children aged 2–4 years. Thirteen isolates were typified. The most common serotype was 19A (23.1%) that together with serotypes 1, 7F and 19F accounted for 69.2% of typified isolates. Serotypes 14, 23F, 12B and 15C were also identified. The 7- and 13-valent pneumococcal conjugate vaccines covered respectively 30.8% and 84.6% of typified IPD cases. One isolate (serotype 15C) was penicillin-resistant and caused meningitis.ConclusionsThe inclusion of the 13-valent pneumococcal conjugate vaccine in immunization programs of young children might be considered to reduce incidence and morbidity of invasive pneumococcal disease in this surveilled population.

Invasive pneumococcal disease among HIV-positive individuals, 2000–2009

To examine invasive pneumococcal disease (IPD) incidence, the impact of the 7-valent pneumococcal conjugate vaccines (PCV7s) programme on the distribution of Streptococcus pneumoniae serotypes and risk factors for IPD among HIV-positive adults. We analysed adults (aged ≥15 years) reported to the HIV and IPD national datasets in England and Wales (2000-2009). Through data-linkage, changes in IPD incidence and serotype distribution were examined. Risk factors for IPD among HIV-positive adults were assessed using a case-control study. Among 63,109 HIV-positive adults, 951 were co-infected with IPD. The average annual incidence of IPD was 245 episodes per 100,000 HIV-positive adults and 246 of 100,000 among those aged 15-44 years. Incidence was higher among those not on antiretroviral therapy (ART) (281 of 100,000) and those with severe immunosuppression (563 of 100,000). Among 9283 adults aged 15-44 at IPD diagnosis, 2.4% were living with undiagnosed HIV. The proportion of IPD episodes in HIV-positive adults with serotypes covered by PCV7 was 23% in 2009, a 54% proportional reduction compared with pre-PCV7 (2000-2006); the reduction in adults of unknown HIV status was 70%. The proportion of IPD episodes among HIV-positive adults caused by serotypes covered by PCV13 was 61%. Significant risk factors for IPD in multivariate analysis included older aged (≥65 years), a lower nadir CD4 cell count and no previous ART. An HIV test should be offered and recommended to adults aged 15-44 years without other obvious IPD risk factors. Our study provides an evidence base to policy makers regarding the use of the new PCV13 in HIV-positive adults.

Invasive pneumococcal disease in non‐Indigenous people in north Queensland, 2001–2009

To compare trends in invasive pneumococcal disease (IPD) in non-Indigenous people in north Queensland before and after the introduction of funded pneumococcal vaccines, and to examine the proportion of cases that occurred after vaccine roll-out that could be vaccine-preventable. In 2005, a 7-valent pneumococcal conjugate vaccine (7vPCV) for non-Indigenous children and a 23-valent pneumococcal polysaccharide vaccine (23vPPV) for non-Indigenous adults aged ≥ 65 years were made freely available. Trends in IPD in the non-Indigenous estimated resident population in north Queensland (about 581 850 in 2006) were compared between the 4 years before (2001-2004) and after (2006-2009) the vaccines were rolled out. Incidences and serotypes of IPD in non-Indigenous people. After the introduction of the vaccines, there were significant declines for all ages in the average annual incidence of IPD (- 34%; P < 0.05) and 7vPCV serotype IPD (- 77%; P < 0.05). In children aged < 5 years, there was a 91% decline in the incidence of 7vPCV serotype IPD (P < 0.05); in adults aged 15-64 years and ≥ 65 years there were 62% and 77% declines, respectively, in 7vPCV and 23vPPV common-serotype IPD (P < 0.05). There was a 188% increase in 23vPPV-only serotype IPD in adults aged 15-64 years (P < 0.05), whereas there was no significant change in adults aged ≥ 65 years. Serotype 19A was the most frequently identified serotype in 2006-2009, causing 19% of all IPD in those 4 years. There is circumstantial evidence that 7vPCV has had a powerful indirect effect in preventing IPD in adults in north Queensland; 23vPPV may have had a direct effect in adults aged ≥ 65 years. It is likely that with combined direct and indirect effects, newer conjugate vaccines could prevent more IPD than could be prevented with the two current vaccines.

Epidemiology of invasive pneumococcal infection in children aged five years and under in Saudi Arabia: a five-year retrospective surveillance study

The epidemiology of invasive pneumococcal disease (IPD) in children aged <or=5 years in Saudi Arabia has not been described. We conducted a retrospective surveillance study to describe the epidemiology of IPD in the population of children aged <or=5 years served by the National Guard Health Affairs hospitals in central and western regions of Saudi Arabia. We reviewed the medical records of children <or=5 years old admitted to the King Abdulaziz Medical City hospitals in Riyadh and Jeddah with pneumococcal infections for the period January 1999 through December 2003. Only microbiologically confirmed IPD cases (meningitis or bacteremia) were included in the analysis. A total of 82 IPD cases, 19 (23.2%) meningitis and 63 (76.8%) bacteremia, were diagnosed during the five-year period. Of these, 12.2% (10/82) died, with a case-fatality slightly but insignificantly higher in cases of meningitis (15.8%) than bacteremia (11.1%). The average annual IPD incidence was 17.4 per 100,000 (4.0 for meningitis and 13.4 for bacteremia). The incidence was roughly similar in males and females (18.3 and 16.6, respectively; p=0.663) and was almost 4-fold higher in the first year of life compared to the next four years (40.6 and 11.5, respectively; p<0.001). The average annual IPD mortality was 2.1 per 100,000 and was higher in the first year of life compared to the next four years (5.2 and 1.3 , respectively; p=0.043). In the pre-vaccination era (1999-2003) in Saudi Arabia, IPD incidence was comparable to the pre-vaccination incidence rates from many industrialized countries, with children aged <or=1 year suffering the highest IPD risk among those aged <or=5 years.

Impact of pneumococcal vaccines on invasive pneumococcal disease in Taiwan

In Taiwan, the 23-valent pneumococcal polysaccharide vaccine (PPV23) and the 7-valent pneumococcal conjugate vaccine (PCV7) have been available since January 2001 and October 2005, respectively. A hospital-based surveillance of invasive pneumococcal disease (IPD) in a medical center was conducted from 2000 to 2008 to evaluate the epidemiologic changes after pneumococcal vaccination. A total of 337 episodes in 328 patients were identified. The cumulative coverage rate of PPV23 among persons of age >or=75 years increased from 12% in 2007 to 41% in 2008, and that of PCV7 among children aged <5 years was 0.7% in 2005 and 25.2% in 2008. The annual incidence of IPD decreased from 6.2 cases per 10,000 hospitalizations in 2000-2005 to 3.8 cases in 2006-2008 (38.5% reduction, P < 0.001), but the fatality rate did not change significantly (24.4% and 21.8%, P = 0.74). The serotype coverage rates of PPV23 and PCV7 were not significantly different between 2000-2005 and 2006-2008 (both P > 0.05). A marked increase of serotype 19A from 2000-2005 (0.5%) to 2006-2008 (11.5%) was found (P < 0.001). In summary, a decline in IPD incidence but not in fatality rate occurred after the availability of PCV7 and the increased usage of PPV23. The rapid emergence of serotype 19A during this period is alarming.

Invasive pneumococcal disease in Danish children, 1996–2007, prior to the introduction of heptavalent pneumococcal conjugate vaccine

The aim of this study was to document the epidemiology, microbiology and outcome of invasive pneumococcal disease (IPD) among children <16 years with quality surveillance data, just prior to the introduction of the heptavalent pneumococcal conjugate vaccine (PCV7) into the Danish routine immunization programme October 2007. Clinical and microbiological records on cases of IPD in children <16 years admitted to Hvidovre Hospital, Denmark 1996-2007, were retrospectively reviewed. We identified 106 cases of IPD. The annual incidence of IPD was 11 per 100 000 in children <16 years, but considerably higher, 62 per 100 000, in children <2 years. Additionally, of the children with pneumococcal meningitis 86% were <2 years. We observed no fatalities. A total of 10% developed sequelae, but of the patients with pneumococcal meningitis 27% developed sequelae. Nine patients had known risk factors. The Streptococcus pneumoniae serotype was available for 81 cases. Seventy-five percent of the IPD cases in children aged <2 years were caused by one of the serotypes contained within PCV7, compared to only 24% in children >/=2 years. Our data indicate that an estimated 75% of all IPD cases among children <2 years are caused by PCV7 serotypes and might therefore be prevented by PCV7 vaccination.

Incidence of invasive pneumococcal disease in the Czech Republic and serotype coverage by vaccines, 1997–2006

We studied the incidence of invasive pneumococcal disease (IPD) in the Czech Republic by analysing two sources of data. The incidence of pneumococcal meningitis based on routine notification data varied between 0.4 and 0.6/100 000 population between 1997 and 2006. The incidence of IPD based on laboratory surveillance varied between 2.3 and 4.3/100 000 population between 2000 and 2006. The annual IPD incidence remained stable during the study period. Estimates of absolute IPD case-load in the entire country varied from 235 to 437 per year. The age-specific incidence was highest in the <1 year age group, reaching 4.3/100 000 for pneumococcal meningitis in routine notification and 15.7/100 000 for IPD in laboratory-based surveillance data, respectively. A total of 1236 Streptococcus pneumoniae isolates from cerebrospinal fluid and sterile body sites were investigated. The most frequent serotypes causing IPD in all ages were 3, 4, 14, 8 and 19F, accounting for 41.5% of all isolates. The most frequent serotypes by age group were: <1 year (6B and 19F); 1-4 years (14, 6B and 23F); 40-64 years (3, 8 and 4), and > or = 65 years (3, 4, 9N and 14). The coverage of serotypes in all age groups by pneumococcal vaccines ranged from 41.5% for 7-valent conjugate vaccine to 67.9% for 13-valent conjugate vaccine. The coverage of serotypes causing IPD is significantly different between infants/children and adults/elderly. PCV-7 coverage by age group was: <1 year (66.0%), 1-4 years (65.1%), 40-64 years (34.4%) and > or = 65 years (39.3%). Similar age differences between infants/children and adults/elderly were found in coverage by PCV-9, PCV-11 and PCV-13. The distribution of serotypes in the total population and individual age groups was stable during the period 2000-2006.