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Objective: To describe the epidemiology of invasive pneumococcal disease (IPD) in a predominantly minority population with low childhood immunization rates and high HIV prevalence, during the early childhood pneumococcal vaccine (PCV7) era., Methods: A retrospective cases series analysis of 131 patients diagnosed with IPD at University Hospital in Newark, NJ from 2000 through 2005, and who had their pneumococcal isolates serotyped, was conducted. Changes in IPD over time were analyzed with the Cochran-Armitage test and linear regression. Multivariate logistic regression was conducted to determine risk factors for non-vaccine type IPD., Results: Ninety-two percent of cases occurred in older children (>or=5 years) and adults, with 53.4% occurring in the 34-49 year-old age group. 90% of cases were black and 48% were HIV-infected. Among cases five years or older, there was a significant decrease in the proportion of IPD caused by vaccine serotypes (2000: 45.5%, 2001: 50.0%, 2002: 31.8%, 2003: 30.0%, 2004: 0.0%, 2005: 0.0%; p<0.0005). Concomitantly, PCV7 immunization rates among Newark infants increased (2002: 30.5%, 2003: 58.1%, 2004: 70.9%, 2005: 75.6%). Risk factors for non-vaccine type IPD included year of diagnosis and older male., Conclusion: At-risk populations, with high HIV prevalence and relatively low infant PCV7 immunization rates, may still be benefiting from PCV7-related herd protection effects.

The recent discovery of a mobile genetic element encoding a pilus-like structure in Streptococcus pneumoniae and the demonstration of a role for the pilus in virulence in mice have led to the proposal of the use of the pilus as a candidate pneumococcal vaccine. We examined the frequency of occurrence of the pneumococcal pilus, as determined by the presence of the rrgC gene, and analyzed its association with virulence, capsular serotypes, and multilocus sequence types in the American Indian pneumococcal collection and isolates of S. pneumoniae from blood cultures collected at Children's Hospital Boston. Overall, 21.4% of strains in the American Indian collection had the rrgC gene, but there was no difference between isolates obtained from the nasopharynx and those obtained from sterile sites (blood or cerebrospinal fluid). Vaccine-type strains were significantly more likely than non-vaccine-type strains to have this pilus gene (P < 0.001). Among isolates with identical multilocus sequence types, there was a high concordance (95%) between the multilocus sequence type and the presence or the absence of rrgC. Finally, in the era of the pneumococcal conjugate vaccine, the frequency of rrgC in isolates from Children's Hospital Boston has decreased significantly (42.8% before 2000 versus 21.3% after 2000; P = 0.019). Therefore, our data show that the pilus is present in a minority of strains and is associated with certain serotypes and that its frequency has been reduced by the conjugate pneumococcal vaccine.

Nasopharyngeal carriage of Streptococcus pneumoniae in unimmunised adults and older children in three remote Australian Aboriginal communities was compared in 2002 and 2004. Universal childhood pneumococcal vaccination with a catch-up program was introduced in late 2001. Carriage prevalence across all age groups of pneumococcal serotypes included in the 7-valent vaccine was 10% in both 2002 and 2004 (12 and 30 months after introduction of vaccination). This carriage prevalence was lower than anticipated. It is likely that indirect effects of childhood vaccination occurred before the 2002 survey. To further assess indirect effects on carriage of childhood pneumococcal vaccination, data prior to 2002 are required. Between 12 and 30 months following introduction of conjugate pneumococcal vaccination, indirect effects on carriage were unchanged.

In 2000, pneumococcal conjugate vaccine (PCV7) was recommended for young children. By 2002-2003, 48.6% had been fully immunized. Using Medicare administrative, we found that the rates of invasive pneumococcal disease (IPD) hospitalizations in the elderly in the 2000-2001, 2001-2002 and 2002-2003, were 22.6, 30.2, and 40.6% lower, respectively, than during the baseline period, 1996-1997 through 1999-2000 (range 35.1/100,000 to 38.3/100,000). Pneumococcal polysaccharide vaccine (PPV23) has been recommended for the elderly, since 1989. PPV23 vaccination rates in the elderly increased by 25.2% during the baseline period but by <5% during the period PCV7 has been available. Thus, during the period that PCV7 vaccine has been used in children, rates of IPD in the elderly have declined appreciably more compared to the immediately prior period when PPV23 was the only vaccine available.

We evaluated invasive pneumococcal disease (IPD), antimicrobial resistance and nasopharyngeal colonization before and after introduction of pneumococcal conjugate vaccine (PCV7) in Alaska Natives (AN), a population with high IPD rates. We obtained IPD rates from population-based surveillance. Colonization was determined from annual surveys among rural AN of all ages and from urban children. After vaccine introduction, vaccine-type IPD rates declined by 91% among AN children <2 years, by 80% among non-Natives <2 years, and by 40% for adults of all races (P<0.001 each). IPD decreased for isolates resistant to penicillin, erythromycin and cotrimoxazole (P<0.001 each). Vaccine-type colonization decreased among rural and urban children <5 years and among rural adults (P<0.001 each). PCV7 vaccine has eliminated a longstanding disparity of vaccine-type IPD for AN children. Decreased vaccine-type colonization and IPD in adults demonstrate indirect vaccine effects.

Background: Heptavalent pneumococcal conjugate vaccine was licensed in the United States in February 2000 and, following national guidelines, universally distributed in Massachusetts starting in July 2000 to children younger than 2 years of age and selected children 2-5 years of age. We performed statewide surveillance for all cases of invasive pneumococcal disease (IPD) in children younger than 18 years of age to determine risk features and contribution of vaccine failure to ongoing pneumococcal invasive disease., Methods: Massachusetts pediatric IPD cases were identified via enhanced passive surveillance of microbiology laboratory reports of pneumococcal isolates from sterile body sites of children younger than 18 years for 2 years starting in October 2001. Serotyping was performed on isolates of Streptococcus pneumoniae from normally sterile body fluid. Case demographic and clinical data (including dates of prior doses of PCV7) were collected via follow-up telephone interviews with case primary care providers and/or parents., Results: Between October 1, 2001 and September 30, 2003, 191 cases of IPD were identified statewide (138 in children younger than 5 years). Annual incidence rate for IPD was 17.4 per 100,000 children younger than 5 years, representing a decline of 69% when compared with annual incidence rate of 56.9 per 100,000 from Massachusetts statewide active surveillance performed 1990-1991. In 2001-2003, 30% of cases occurred in the first year of life (36.5 per 100,000), representing a 7.8-fold increased risk compared with children older than 1 year of age. Race-specific annual incidence rates in blacks and Hispanics were 2.3-fold (95% confidence interval, 1.21-4.42) and 1.9-fold (95% confidence interval, 1.06-3.37), greater than in whites. Fifty-nine cases were reported to have underlying comorbid conditions. Serotyping was available for 136 of 191 (71%) cases younger than 18 years; of isolates available for serotyping, 40 (29%) were vaccine serotype (ST), 31 (23%) vaccine-related ST and 65 (48%) nonvaccine ST. Seven of 40 cases with IPD caused by vaccine ST received at least 3 doses of PCV7 vaccine before IPD., Conclusions: Universal administration of PCV7 to children younger than 2 years of age and selective administration to children 2-5 years of age has resulted in a significant decline in IPD in Massachusetts. Children younger than 1 year of age, African American and Hispanic children and those with recognized comorbid illnesses (malignancy, human immunodeficiency virus, immune deficiency, nephrotic syndrome, etc.) continue to remain at risk for IPD. These risk features should be considered when evaluating febrile infants and children.