Effectiveness of 13-Valent Pneumococcal Conjugate Vaccine Against Invasive Disease Caused by Serotype 3 in Children: A Systematic Review and Meta-analysis of Observational Studies.

The 13-valent pneumococcal conjugate vaccine (PCV13) is the only licensed PCV with serotype 3 polysaccharide in its formulation. Postlicensure PCV13 effectiveness studies against serotype 3 invasive pneumococcal disease (IPD) in children have shown inconsistent results.  We performed a systematic review and meta-analysis of observational studies to assess PCV13 vaccine effectiveness (VE) for serotype 3 IPD in children. We systematically searched PubMed, Embase, and the Cochrane library for studies published before 14 August 2017. We identified 4 published studies and 2 conference posters that provided PCV13 VE estimates stratified by serotype. The pooled PCV13 VE against serotype 3 IPD from the random-effects meta-analysis was 63.5% (95% confidence interval [CI], 37.3%-89.7%). A sensitivity analysis including conference posters gave a pooled VE estimate of 72.4% (95% CI, 56.7%-88.0%). The pooled data from case-control studies with similar methodologies and high quality support direct PCV13 protection against serotype 3 IPD in children.

Effectiveness of 13-Valent Pneumococcal Conjugate Vaccine Against Hospitalization for Community-Acquired Pneumonia in Older US Adults: A Test-Negative Design.

Background: Following universal recommendation for use of 13-valent pneumococcal conjugate vaccine (PCV13) in US adults aged ≥65 years in September 2014, we conducted the first real-world evaluation of PCV13 vaccine effectiveness (VE) against hospitalized vaccine-type community-acquired pneumonia (CAP) in this population. Methods: Using a test-negative design, we identified cases and controls from a population-based surveillance study of adults in Louisville, Kentucky, who were hospitalized with CAP. We analyzed a subset of CAP patients enrolled 1 April 2015 through 30 April 2016 who were aged ≥65 years and consented to have their pneumococcal vaccination history confirmed by health insurance records. Cases were defined as hospitalized CAP patients with PCV13 serotypes identified via culture or serotype-specific urinary antigen detection assay. Remaining CAP patients served as test-negative controls. Results: Of 2034 CAP hospitalizations, we identified PCV13 serotypes in 68 (3.3%) participants (ie, cases), of whom 6 of 68 (8.8%) had a positive blood culture. Cases were less likely to be immunocompromised (29.4% vs 46.4%, P = .02) and overweight or obese (41.2% vs 58.6%, P = .01) compared to controls, but were otherwise similar. Cases were less likely to have received PCV13 than controls (3/68 [4.4%] vs 285/1966 [14.5%]; unadjusted VE, 72.8% [95% confidence interval, 12.8%-91.5%]). No confounding was observed during adjustment for patient characteristics, including immunocompromised status, body mass index, and history of influenza and pneumococcal polysaccharide vaccination (adjusted VE range, 71.1%-73.3%). Conclusions: Our study is the first to demonstrate real-world effectiveness of PCV13 against vaccine-type CAP in adults aged ≥65 years following introduction into a national immunization program.

Boceprevir for previously treated chronic HCV genotype 1 infection.

BACKGROUND: In patients with chronic infection with hepatitis C virus (HCV) genotype 1 who do not have a sustained response to therapy with peginterferon-ribavirin, outcomes after retreatment are suboptimal. Boceprevir, a protease inhibitor that binds to the HCV nonstructural 3 (NS3) active site, has been suggested as an additional treatment. METHODS: To assess the effect of the combination of boceprevir and peginterferon-ribavirin for retreatment of patients with chronic HCV genotype 1 infection, we randomly assigned patients (in a 1:2:2 ratio) to one of three groups. In all three groups, peginterferon alfa-2b and ribavirin were administered for 4 weeks (the lead-in period). Subsequently, group 1 (control group) received placebo plus peginterferon-ribavirin for 44 weeks; group 2 received boceprevir plus peginterferon-ribavirin for 32 weeks, and patients with a detectable HCV RNA level at week 8 received placebo plus peginterferon-ribavirin for an additional 12 weeks; and group 3 received boceprevir plus peginterferon-ribavirin for 44 weeks. RESULTS: A total of 403 patients were treated. The rate of sustained virologic response was significantly higher in the two boceprevir groups (group 2, 59%; group 3, 66%) than in the control group (21%, P<0.001). Among patients with an undetectable HCV RNA level at week 8, the rate of sustained virologic response was 86% after 32 weeks of triple therapy and 88% after 44 weeks of triple therapy. Among the 102 patients with a decrease in the HCV RNA level of less than 1 log(10) IU per milliliter at treatment week 4, the rates of sustained virologic response were 0%, 33%, and 34% in groups 1, 2, and 3, respectively. Anemia was significantly more common in the boceprevir groups than in the control group, and erythropoietin was administered in 41 to 46% of boceprevir-treated patients and 21% of controls. CONCLUSIONS: The addition of boceprevir to peginterferon-ribavirin resulted in significantly higher rates of sustained virologic response in previously treated patients with chronic HCV genotype 1 infection, as compared with peginterferon-ribavirin alone. (Funded by Schering-Plough [now Merck]; HCV RESPOND-2 ClinicalTrials.gov number, NCT00708500.).

Anemia during treatment with peginterferon Alfa-2b/ribavirin and boceprevir: Analysis from the serine protease inhibitor therapy 2 (SPRINT-2) trial.

UNLABELLED: Boceprevir (BOC) added to peginterferon alfa-2b (PegIFN) and ribavirin (RBV) significantly increases sustained virologic response (SVR) rates over PegIFN/RBV alone in previously untreated adults with chronic hepatitis C genotype 1. We evaluate the relationship of incident anemia with triple therapy. A total of 1,097 patients received a 4-week lead-in of PegIFN/RBV followed by: (1) placebo plus PegIFN/RBV for 44 weeks (PR48); (2) BOC plus PegIFN/RBV using response-guided therapy (BOC/RGT); and (3) BOC plus PegIFN/RBV for 44 weeks (BOC/PR48). The management of anemia (hemoglobin [Hb]<10 g/dL) included RBV dose reduction and/or erythropoietin (EPO) use. A total of 1,080 patients had ≥1 Hb measurement during treatment. The incidence of anemia was 50% in the BOC arms combined (363/726) and 31% in the PR48 arm (108/354, P<0.001). Among BOC recipients, lower baseline Hb and creatinine clearance were associated with incident anemia. In the BOC-containing arms, anemia was managed by the site investigators as follows: EPO without RBV dose reduction, 38%; RBV dose reduction without EPO, 8%; EPO with RBV dose reduction, 40%; and neither RBV dose reduction nor EPO, 14%. SVR rates were not significantly affected by management strategy (70%-74%), and overall patients with anemia had higher rates of SVR than those who did not develop anemia (58%). Serious and life-threatening adverse events (AEs) and discontinuations due to AEs among BOC-treated patients did not differ by EPO use. CONCLUSION: With BOC/PR therapy, SVR rates in patients with incident anemia were higher than nonanemic patients and did not vary significantly according to the investigator-selected approach for anemia management. Prospective studies are needed to confirm this observation.

Overall safety profile of boceprevir plus peginterferon alfa-2b and ribavirin in patients with chronic hepatitis C genotype 1: a combined analysis of 3 phase 2/3 clinical trials.

BACKGROUND & AIMS: Triple therapy with peginterferon/ribavirin (PR) plus an NS3 protease inhibitor has emerged as the standard-of-care for patients with chronic hepatitis C genotype-1. We provide a detailed safety analysis comparing PR to boceprevir plus PR (BOC/PR) across three phase 2/3 studies. METHODS: SPRINT-1 was an open-label phase 2 study in 595 treatment-naive patients. In the two phase 3 studies, 1500 patients (1097 treatment-naive, SPRINT-2; 403 treatment-failure, RESPOND-2) were randomized to receive PR alone, or one of two regimens where BOC was added to PR after a 4-wk PR lead-in. In this analysis, the respective BOC/PR and PR arms were combined for all three trials. The benefit of shortened duration of treatment using response-guided therapy (RGT) was also explored in the SPRINT-2 trial. RESULTS: Only two adverse events, anaemia and dysgeusia, occurred 20% more often with the BOC-containing regimens compared with PR. Nausea, diarrhoea and neutropenia were the only other common events with an incidence of at least 5% greater when BOC was added to the PR backbone. The proportions of patients reporting serious adverse events (AE), life-threatening AEs, and study drug discontinuation because of an AE were similar in the PR and BOC/PR arms. In treatment-naive patients, RGT generally did not result in a lower frequency of common AEs; however, RGT led to decreased exposure to all 3 study drugs and to a decrease in the mean duration of several clinically relevant AEs such as anaemia, neutropenia, fatigue and depression, as well as earlier normalization of haemoglobin and neutrophil counts. CONCLUSIONS: The safety profile of BOC combination therapy largely reflects the known profile of peginterferon and ribavirin, with incremental haematolgical effects and dysgeusia. Shorter treatment duration with RGT significantly reduced the duration of AEs.

Boceprevir with peginterferon alfa-2a-ribavirin is effective for previously treated chronic hepatitis C genotype 1 infection.

BACKGROUND & AIMS: The addition of boceprevir to therapy with peginterferon alfa-2b and ribavirin results in significantly higher rates of sustained virologic response (SVR) in previously treated patients with chronic hepatitis C virus (HCV) genotype-1 infection, compared with peginterferon alfa-2b and ribavirin alone. We assessed SVR with boceprevir plus peginterferon alfa-2a-ribavirin (PEG2a/R) in patients with identical study entry criteria. METHODS: In a double-blind, placebo-controlled trial, 201 patients with HCV genotype-1 who had relapsed or not responded to previous therapy were assigned to groups (1:2) and given a 4-week lead-in phase of PEG2a/R, followed by placebo plus PEG2a/R for 44 weeks (PEG2a/R) or boceprevir plus PEG2a/R for 44 weeks (BOC/PEG2a/R). The primary end point was SVR 24 weeks after therapy ended. RESULTS: The addition of boceprevir after 4 weeks of lead-in therapy with PEG2a/R significantly increased the rate of SVR from 21% in the PEG2a/R group to 64% in the BOC/PEG2a/R group (P < .0001). Among patients with poor response to interferon therapy (<1-log(10) decline in HCV RNA at week 4), 39% in the BOC/PEG2a/R group had SVRs, compared with none of the patients in the PEG2a/R group. Among patients with good response to interferon (≥1-log(10) decline), 71% in the BOC/PEG2a/R group had SVRs, compared with 25% in the PEG2a/R group. A ≥1-log(10) decline in HCV RNA at treatment week 4 was the strongest independent predictor of SVR, exceeding that of IL-28B genotype. Among 8 patients who began the study with HCV amino acid variants associated with boceprevir resistance, 3 (38%) achieved SVRs. Fifty percent of patients in the BOC/PEG2a/R group developed anemia (hemoglobin <10.0 g/dL), compared with 27% in the PEG2a/R group; 43% vs 21%, respectively, developed neutropenia (neutrophil count <750/mm(3)). CONCLUSIONS: The addition of boceprevir after 4 weeks of lead-in therapy with PEG2a/R caused significantly higher rates of SVR in previously treated patients with chronic HCV genotype-1 infection, compared with patients given only PEG2a/R. ClinicalTrials.gov Identifier: NCT00845065.

Factors that predict response of patients with hepatitis C virus infection to boceprevir.

BACKGROUND & AIMS: Little is known about factors associated with a sustained virologic response (SVR) among patients with hepatitis C virus (HCV) infection to treatment with protease inhibitors. METHODS: Previously untreated patients (from the Serine Protease Inhibitor Therapy 2 [SPRINT-2] trial) and those who did not respond to prior therapy (from the Retreatment with HCV Serine Protease Inhibitor Boceprevir and PegIntron/Rebetol 2 [RESPOND-2] trial) received either a combination of peginterferon and ribavirin for 48 weeks or boceprevir, peginterferon, and ribavirin (triple therapy) after 4 weeks of peginterferon and ribavirin (total treatment duration, 28-48 wk). A good response to interferon was defined as a ≥ 1 log(10) decrease in HCV RNA at week 4; a poor response was defined as a <1 log(10) decrease. We used multivariate regression analyses to identify baseline factors of the host (including the polymorphism interleukin [IL]-28B rs12979860) associated with response. The polymorphism IL-28B rs8099917 also was assessed. RESULTS: In the SPRINT-2 trial, factors that predicted a SVR to triple therapy included low viral load (odds ratio [OR], 11.6), IL-28B genotype (rs 12979860 CC vs TT and CT; ORs, 2.6 and 2.1, respectively), absence of cirrhosis (OR, 4.3), HCV subtype 1b (OR, 2.0), and non-black race (OR, 2.0). In the RESPOND-2 trial, the only factor significantly associated with a SVR was previous relapse, compared with previous nonresponse (OR, 2.6). Most patients with rs12979860 CC who received triple therapy had undetectable levels of HCV RNA by week 8 (76%-89%), and were eligible for shortened therapy. In both studies, IL-28B rs12979860 CC was associated more strongly with a good response to interferon than other baseline factors; however, a ≥ 1 log(10) decrease in HCV-RNA level at week 4 was associated more strongly with SVR than IL-28B rs12979860. Combining the rs8099917 and rs12979860 genotypes does not increase the association with SVR. CONCLUSIONS: The CC polymorphism at IL-28B rs12979860 is associated with response to triple therapy and can identify candidates for shorter treatment durations. A ≥ 1 log(10) decrease in HCV RNA at week 4 of therapy is the strongest predictor of a SVR, regardless of polymorphisms in IL-28B.

Proximity of first sexual intercourse to menarche and risk of high-grade cervical disease.

BACKGROUND: We assessed if risk of developing cervical intraepithelial neoplasia grade 2/3 (CIN2/3) or adenocarcinoma in situ (AIS) is associated with a short interval between menarche and first sexual intercourse (FSI). METHODS: A total of 1009 Colombian and 1012 Finnish females, aged 16-23, who were enrolled in the phase 3 trials of a quadrivalent human papillomavirus (HPV) 6/11/16/18 vaccine had nonmissing data for age of menarche and FSI. The impact of menarche interval on the odds of developing CIN2-3/AIS was evaluated in placebo recipients who were DNA negative to HPV 6/11/16/18/31/33/35/39/45/51/52/56/58/59 and seronegative to HPV 6/11/16/18 at day 1, and had a normal Pap result at day 1 and month 7, thus approximating sexually naive adolescents (n = 504). RESULTS: The mean age of menarche and FSI was 12.4 and 16.0 years, respectively. Among the women approximating sexually naive adolescents, 18 developed CIN2-3/AIS. Compared with women who postponed FSI beyond 3 years of menarche, those with FSI within 3 years of menarche had a greater risk of cytologic abnormalities (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.02-2.68; P = .04) and CIN2-3/AIS (OR, 3.56; 95% CI, 1.02-12.47; P = .05). CONCLUSIONS: A short interval between menarche and FSI was a risk factor for cytologic abnormalities and high-grade cervical disease. These data emphasize the importance of primary prevention through education and vaccination. CLINICAL TRIALS REGISTRATION: NCT00092521 and NCT00092534.

The broader impacts of otitis media and sequelae for informing economic evaluations of pneumococcal conjugate vaccines.

INTRODUCTION: Otitis media (OM) is a common childhood infection. Pneumococcal conjugate vaccines (PCVs) prevent OM episodes, thereby reducing short- and long-term clinical, economic, humanistic, and societal consequences. Most economic evaluations of PCVs focus on direct health gains and cost savings from prevented acute episodes but do not fully account for the broader societal impacts of OM prevention. AREAS COVERED: This review explores the broader burden of OM on children, caregivers, and society to better inform future economic evaluations of PCVs. EXPERT OPINION: OM causes a substantial burden to society through long-term sequelae, productivity losses, reduced quality of life for children and caregivers, and contribution to antimicrobial resistance from inappropriate antibiotic use. The effect of PCVs on acute OM has been recognized globally, yet the broader impact has not been consistently quantified, studied, or communicated. Economic evaluations of PCVs must evolve to include broader effects for patients, caregivers, and society from OM prevention. Future PCVs with broader coverage may further reduce OM incidence and antimicrobial resistance, but optimal uptake will depend on increasing the recognition and use of novel frameworks that include broader benefits. Communicating the full value of PCVs to decision makers may result in wider access and positive societal returns.

The accuracy of colposcopic biopsy: analyses from the placebo arm of the Gardasil clinical trials.

We evaluated the overall agreement between colposcopically directed biopsies and the definitive excisional specimens within the context of three clinical trials. A total of 737 women aged 16-45 who had a cervical biopsy taken within 6 months before their definitive therapy were included. Per-protocol, colposcopists were to also obtain a representative cervical biopsy immediately before definitive therapy. Using adjudicated histological diagnoses, the initial biopsies and the same day biopsies were correlated with the surgically excised specimens. The overall agreement between the biopsies taken within 6 months of definitive therapy, and the definitive therapy diagnoses was 42% (weighted kappa = 0.34) (95% CI: 0.29-0.39). The overall underestimation of cervical intraepithelial neoplasia grade 2/3 or adenocarcinoma in situ (CIN2-3/AIS) and CIN3/AIS was 26 and 42%, respectively. When allowing for one degree of variance in the correlation, the overall agreement was 92% for CIN2-3/AIS. The overall agreement between the same day biopsy and definitive therapy specimen was 56% (weighted kappa = 0.41) (95% CI: 0.36-0.47), and the underestimation of CIN2-3/AIS was 57%. There were significant associations in the agreement between biopsies and excisional specimen diagnoses when patients were stratified by age, number of biopsies, lesion size, presence of human papillomavirus (HPV)16/18 and region. Of 178 diagnostic endocervical curettages performed, 14 (7.9%) found any HPV disease. Colposcopic accuracy improved when CIN2 and CIN3/AIS were grouped as a single predictive measure of high-grade disease. Colposcopy functioned well when allowed a one-degree difference between the biopsy and the surgical histologic interpretations, as done in clinical practice. Taking more than one biopsy improved colposcopic accuracy and could improve patient management.

Impact of an HPV6/11/16/18 L1 virus-like particle vaccine on progression to cervical intraepithelial neoplasia in seropositive women with HPV16/18 infection.

The impact of a human papillomavirus (HPV) vaccine on development of cervical intraepithelial neoplasia grade 2-3 or adenocarcinoma in situ (CIN2-3/AIS) in women with ongoing HPV16 or 18 infections prevaccination is reported. Seventeen thousand six-hundred and twenty-two women aged 16-26 were enrolled in 1 of 2 randomized, placebo-controlled, efficacy trials (Protocols 013 and 015). Vaccine or placebo was given at day 1, month 2 and 6. Women were tested for HPV6/11/16/18 DNA and antibodies at day 1. We focus on the subset of women who were seropositive and DNA positive to HPV16 or HPV18 prevaccination. Incidence is expressed as the number of women with an endpoint per 100 person-years-at-risk. In total, 419 vaccine and 446 placebo recipients were both seropositive and DNA positive to HPV16 or HPV18 prevaccination and had at least one follow-up visit. In Protocol 013, the incidence of HPV16/18-related CIN2-3/AIS among these women was 10.9 in the vaccine arm and 7.0 in the placebo arm (vaccine efficacy = -54.9; 95% CI: -181.7, 13.0). In Protocol 015, the incidence of HPV16/18-related CIN2-3/AIS was 5.5 in the vaccine arm and 6.2 in the placebo arm (vaccine efficacy = 12.2%; 95% CI: -29.8, 40.9). These data suggest HPV vaccination neither reduces nor enhances progression to HPV16/18-related high grade cervical lesions, and cervical cytology screening and corresponding management should continue as per local recommendations. Ultimately, population-based surveillance of vaccinated individuals beyond these clinical trials will be required to further address questions regarding the impact of vaccination in women exposed to vaccine HPV types before vaccination.

Adenocarcinoma in situ and associated human papillomavirus type distribution observed in two clinical trials of a quadrivalent human papillomavirus vaccine.

The primary objective of this report is to describe the detection of adenocarcinoma in situ (AIS) and associated human papillomavirus (HPV) type distribution that was observed in the context of two phase 3 clinical trials of a quadrivalent HPV6/11/16/18 vaccine. In this intention-to-treat analysis, we include all women who had at least one follow-up visit postenrollment. Healthy women (17,622) aged 15-26 with no history of HPV disease and a lifetime number of less than five sex partners (average follow-up of 3.6 years) were randomized (1:1) to receive vaccine or placebo at day 1, months 2, and 6. Women underwent colposcopy and biopsy according to a Papanicolaou triage algorithm. All tissue specimens were tested for 14 HPV types and were adjudicated by a pathology panel. During the trials, 22 women were diagnosed with AIS (six vaccine and 16 placebo). There were 25 AIS lesions in total, with HPV16/18 present in 96% (24 of 25 with 15 of 25 as single infections). Only two of 22 women had concomitant cytology results suggesting glandular abnormality. Colposcopic impressions (25 total) were either negative or indicated squamous lesions only. Of women with AIS, all six in the vaccine cohort and seven of 16 in the placebo cohort were infected at baseline with the same HPV type that was detected in the AIS lesion. Concurrent squamous lesions were detected in 20 of these 22 women. In summary, our findings show that AIS evades colposcopic and cervical cytologic detection. As most AIS lesions were HPV16/18-related, prophylactic HPV vaccination should reduce the incidence of invasive adenocarcinoma.

Chlamydia trachomatis infection and risk of cervical intraepithelial neoplasia.

OBJECTIVES: High-risk human papillomavirus (hrHPV) is the primary cause of cervical cancer. As Chlamydia trachomatis is also linked to cervical cancer, its role as a potential co-factor in the development of cervical intraepithelial neoplasia (CIN) grade 2 or higher was examined. METHODS: The placebo arms of two large, multinational, clinical trials of an HPV6/11/16/18 vaccine were combined. A total of 8441 healthy women aged 15-26 years underwent cervicovaginal cytology (Papanicolaou (Pap) testing) sampling and C trachomatis testing at day 1 and every 12 months thereafter for up to 4 years. Protocol-specified guidelines were used to triage participants with Pap abnormalities to colposcopy and definitive therapy. The main outcome measured was CIN. RESULTS: At baseline, 2629 (31.1%) tested positive for hrHPV DNA and 354 (4.2%) tested positive for C trachomatis. Among those with HPV16/18 infection (n = 965; 11.4%) or without HPV16/18 infection (n = 7382, 87.5%), the hazard ratios (HRs) associated with development of any CIN grade 2 according to baseline C trachomatis status were 1.82 (95% CI: 1.06 to 3.14) and 1.74 (95% CI 1.05 to 2.90), respectively. The results were comparable when only the 12 most common hrHPV infections were considered, but the excess risk disappeared when the outcome was expanded to include CIN grade 3 or worse. CONCLUSION: Further studies based on larger cohorts with longitudinal follow-up in relation to the C trachomatis acquisition and a thorough evaluation of temporal relationships of infections with hrHPV types, C trachomatis and cervical neoplasia are needed to demonstrate whether and how in some situations C trachomatis sets the stage for cervical carcinogenesis. Trial registration NCT00092521 and NCT00092534.

Pneumococcal Conjugate Vaccine Impact on Serotype 3: A Review of Surveillance Data.

INTRODUCTION: Limited changes in serotype 3 invasive pneumococcal disease (IPD) incidence rates after a decade of 13-valent pneumococcal conjugate vaccine (PCV13) introduction into several national immunization programs (NIP) have raised questions about PCV13's effectiveness against this serotype. METHODS: We analyzed the impact of pediatric PCV programs on serotype 3 IPD with two approaches. First, we reviewed the publicly available surveillance data from countries identified in two recently published reviews to describe the population impact of pediatric PCV13 or PCV10 vaccination programs on serotype 3 IPD. We then compared the observed trends in PCV10 and PCV13 countries to a previously described dynamic transmission model that simulates the spread of pneumococcal carriage and development of IPD in a population over time. RESULTS: When serotype 3 disease rates are compared from countries that have introduced either a 10-valent (PCV10) vaccine that does not contain serotype 3 in its formulation or PCV13 in their pediatric NIP, over time, serotype 3 incidence rate trends are markedly different. Countries with a PCV10 NIP showed a substantial linear increase in serotype 3 pneumococcal disease among all age groups since the time of PCV10 introduction, whereas countries with a PCV13 NIP experienced a modest decline during the 3-4 years after vaccine introduction followed by an inflection upward in subsequent years. CONCLUSION: These data suggest that PCV13 provides a certain degree of direct and indirect protection against serotype 3 at the population level and direct adult vaccination with a serotype 3-containing vaccine is likely to provide substantial benefit in the context of a pediatric PCV NIP. Further research around serotype 3 transmission patterns and epidemiology is nonetheless warranted.

Public health impact of pneumococcal conjugate vaccination: a review of measurement challenges.

INTRODUCTION: Modeling analyses have attempted to quantify the global impact of pneumococcal conjugate vaccines (PCVs) on pneumococcal disease (PD), however these pediatric models face several challenges in obtaining comprehensive impact measurements. AREAS COVERED: We present several measurement challenges and discuss examples from recently published pediatric modeling evaluations. Challenges include estimating the number of infants fully or partially vaccinated with PCVs, inclusion of indirect effects of vaccination, accounting for various dosing schedules, capturing effect of PCVs on nonspecific, noninvasive PD, and inclusion of adult PCV use. EXPERT OPINION: The true impact of PCVs has been consistently underestimated in published analyses due to multiple measurement challenges. Nearly 100 million adults are estimated to have received PCV13 over the last decade globally, potentially preventing up to 662 thousand cases of PD. Approximately 4.1 million cases of invasive PD alone may have been averted through indirect protection. Estimates of PCV impact on noninvasive PD remain a challenge due to altered epidemiology. Program switches, incomplete vaccination, and private market uptake among children also confound PD impact estimates. Taken together, the number of averted PD cases from PCV use in the last ten years may be up to three times higher than estimated in previous studies.

Quadrivalent vaccine against human papillomavirus to prevent anogenital diseases.

BACKGROUND: A phase 3 trial was conducted to evaluate the efficacy of a prophylactic quadrivalent vaccine in preventing anogenital diseases associated with human papillomavirus (HPV) types 6, 11, 16, and 18. METHODS: In this randomized, placebo-controlled, double-blind trial involving 5455 women between the ages of 16 and 24 years, we assigned 2723 women to receive vaccine and 2732 to receive placebo at day 1, month 2, and month 6. The coprimary composite end points were the incidence of genital warts, vulvar or vaginal intraepithelial neoplasia, or cancer and the incidence of cervical intraepithelial neoplasia, adenocarcinoma in situ, or cancer associated with HPV type 6, 11, 16, or 18. Data for the primary analysis were collected for a per-protocol susceptible population of women who had no virologic evidence of HPV type 6, 11, 16, or 18 through 1 month after administration of the third dose. RESULTS: The women were followed for an average of 3 years after administration of the first dose. In the per-protocol population, those followed for vulvar, vaginal, or perianal disease included 2261 women (83%) in the vaccine group and 2279 (83%) in the placebo group. Those followed for cervical disease included 2241 women (82%) in the vaccine group and 2258 (83%) in the placebo group. Vaccine efficacy was 100% for each of the coprimary end points. In an intention-to-treat analysis, including those with prevalent infection or disease caused by vaccine-type and non-vaccine-type HPV, vaccination reduced the rate of any vulvar or vaginal perianal lesions regardless of the causal HPV type by 34% (95% confidence interval [CI], 15 to 49), and the rate of cervical lesions regardless of the causal HPV type by 20% (95% CI, 8 to 31). CONCLUSIONS: The quadrivalent vaccine significantly reduced the incidence of HPV-associated anogenital diseases in young women. (ClinicalTrials.gov number, NCT00092521 [ClinicalTrials.gov].).

Streptococcus pneumoniae serotype distribution and antimicrobial nonsusceptibility trends among adults with pneumonia in the United States, 2009‒2017.

Background In the United States, the 13-valent pneumococcal conjugate vaccine has been recommended for children since 2010 and for adults aged ≥65 years since 2014. We assessed S. pneumoniae antimicrobial nonsusceptibility among adults with suspected pneumonia from hospital settings. Methods Isolates were collected from 105 US sites between 2009 and 2017 in the SENTRY Antimicrobial Surveillance Program. Clinical and Laboratory Standards Institute methods were used for susceptibility testing. Serotypes were determined by cpsB sequence obtained by PCR or whole genome sequencing, plus multiplex PCR and/or Neufeld Quellung reactions as needed. Findings Of 7254 S. pneumoniae isolates analyzed, 63.6% and 36.4% were from patients aged 18‒64 and ≥65 years, respectively. Among all isolates, penicillin and ceftriaxone nonsusceptibility declined by 72.3% and 73.8%, respectively, with smaller changes observed for other antibiotics. Nonsusceptibility patterns were serotype-specific; for example, nonsusceptibility was relatively stable for serotype 19A but declined for 19F. Simultaneously, the percentage of serotype 19A isolates decreased from 17.4% to 3.9%, whereas for serotype 19F this percentage increased from 2.8% to 5.0%. The percentage of serotype 3 isolates that were nonsusceptible increased for select antibiotic classes, and the percentage of serotype 3 among all isolates increased minimally from 10.2% to 11.8%. Interpretation Overall pneumococcal nonsusceptibility patterns were influenced by distinct patterns within serotypes, indicating the likelihood of serotype-specific resistance mechanisms. Serotype 19A observations were consistent with vaccine-induced reductions in circulation with no change in the organism susceptibility, whereas the nonsusceptibility increases for serotypes 3 and 19F may indicate circulation of more antibiotic-resistant clones.

Health and Economic Impact of Routine Pediatric Pneumococcal Immunization Programs in Canada: A Retrospective Analysis.

OBJECTIVE: A model was developed to estimate the historical impact (including total societal health and economic benefit) of pneumococcal conjugate vaccine (PCV) programs in the overall Canadian population between 2005 and 2015, inclusively. METHODS: Historical incidence of invasive pneumococcal disease (IPD), pneumonia, and acute otitis media (AOM) were obtained from epidemiologic databases supplemented with published and unpublished data. Two scenarios were considered: (1) the observed historical incidence from 2005 to 2015 in the setting of PCV use; (2) a hypothetical scenario in which we estimated the number of disease cases assuming no PCV use. Disease cases averted as a result of PCV programs were calculated by subtracting the number of observed historical cases from the number of estimated cases expected in the absence of PCV use. RESULTS: PCV programs were estimated to have saved 6631 lives and averted 14,990 IPD cases, 735,700 pneumonia episodes, and 3,697,993 AOM episodes. Positive clinical outcomes resulted in total cost savings of CAD $1.76 billion over 11 years. Vaccination costs were offset by the direct medical cost savings from fewer cases of IPD, pneumonia, and AOM. CONCLUSIONS: Canadian PCV programs have provided significant health benefits and resulted in a substantial value for money. Net savings achieved over the reviewed period would have provided funding for $1.76 billion in other health care costs or public health initiatives. These findings highlight the importance of considering the total value of a vaccination program, rather than vaccine acquisition costs only, when assessing the value of immunization programs.

Incidence and risk factors for genital Chlamydia trachomatis infection: a 4-year prospective cohort study.

BACKGROUND: Few long-term studies reporting incidence and behavioral data for Chlamydia trachomatis (CT) infection in the general population have been published. Such studies are important to understand risk factors associated with infection and to develop screening recommendations. METHODS: A fixed prospective 4-year cohort study of 898 sexually active Norwegian women, aged 16 to 23 years at study start, was conducted to assess incidence, repeat infection, and risk factors associated with genital CT infection. Participants were interviewed at study start and at 6-month intervals thereafter for behavioral characteristics. The women were tested for CT infection at 12-month intervals beginning at study start. Risk factors were assessed using Fisher exact test and conditional logistic regression. Person-time was estimated in survival analyses and incidence of CT infection was reported as events per 100 woman-years. RESULTS: Median duration of observation was 48.0 months (range 10-74) whereas 4.4 specimens were collected per woman (range 2-5). Of the 836 women eligible for the analysis, 19 (2.2%) had a prevalent infection at baseline. The 4-year cumulative incidence of CT infection was 7.7 (95% CI: 6.7-8.7) with annual incidences ranging from 1.2 to 2.9 per 100 woman-years. The 2-year cumulative incidence of repeat CT infection was 11.2 (95% CI: 9.3-13.1) per 100 woman-years. In multivariate analyses, factors associated with incident CT infection were young age (< or =24 years) and number of new partners over the last 12 months prior being tested. CONCLUSION: The annual incidences observed for women 24 years or younger with 1 or more new partners over the last 12 months support recommendations for annual testing for CT in this age group in Norway.

Baseline characteristics and prevalence of HPV 6, 11, 16, 18 in young German women participating in phase III clinical trials of a quadrivalent HPV (6/11/16/18) vaccine.

INTRODUCTION: As limited data among German women exist about HPV, Chlamydia trachomatis (CT) and Neisseria gonorrhoeae, we report the prevalence of these genital infections and general baseline demographics of the young German women enrolled in the phase III trials of the quadrivalent HPV vaccine. MATERIALS AND METHODS: German females (n = 437; 9-23 years) were recruited among 3 international phase 3 studies of an HPV-6/11/16/18 vaccine. We present baseline characteristics, prevalence of HPV-6/11/16/18 and, for women aged 16-23, abnormal cervical cytology and sexually transmitted diseases. RESULTS: Chlamydia trachomatis and Neisseria gonorrhoeae prevalence was 5 and 0.3%, respectively. Approximately 17% of participants had HPV-6, 11, 16, or 18 DNA or antibodies. All subjects <17 years were naïve to the four vaccine types. DISCUSSION: The results of the vaccine trials have demonstrated that it is worth administering prophylactic HPV vaccines before sexual debut; however, none of these sexually active German women were positive to all four types and most were positive to only one type. Thus, all women had the potential to benefit from vaccination with a quadrivalent HPV vaccine.