Burden of herpes zoster in 16 selected immunocompromised populations in England: a cohort study in the Clinical Practice Research Datalink 2000-2012.

OBJECTIVES: Herpes zoster (HZ) is caused by reactivation of varicella-zoster virus which remains latent in individuals after a varicella infection. It is expected that HZ will be more frequent in immunocompromised (IC) individuals than in immunocompetent (IC-free). This study assessed the incidence rate (IR) of HZ in individuals with a wide set of IC conditions and in IC-free individuals. SETTING: A retrospective cohort study was conducted in England using data (January 2000 to March 2012) from the Clinical Practice Research Datalink with linkage to the Hospital Episodes Statistics. PARTICIPANTS: A cohort of 621 588 individuals with 16 selected IC conditions and a gender/age-matched cohort of IC-free individuals were identified. The IC conditions included haematopoietic stem cell transplant (HSCT), solid organ transplant, malignancies, autoimmune diseases and users of immunosuppressive medications. OUTCOMES: IR of HZ per 1000 person-years (PY) was estimated. Proportions of postherpetic neuralgia (PHN) and other HZ complications within 90 days of HZ onset were also estimated among patients with HZ. Risk factors for PHN in IC individuals with HZ were assessed by a multivariate regression model. RESULTS: The overall IR of HZ in the IC cohort was 7.8/1000 PY (95% CI 7.7 to 7.9), increasing with age from 3.5/1000 PY (3.4-3.7) in individuals aged 18-49 years to 12.6/1000 PY (12.2-13.0) in individuals aged ≥80 years. This IR in the IC-free cohort was 6.2/1000 PY (6.1-6.3). The overall IR of HZ varied across IC conditions, ranging from 5.3 (5.1-5.5) in psoriasis to 41.7/1000 PY (35.7-48.4) in HSCT. The proportions of PHN and other HZ complications were 10.7% (10.2-11.1) and 2.9% (2.7-3.2) in the IC cohort, but 9.1% (8.7-9.5) and 2.3% (2.1-2.6) in the IC-free cohort, respectively. CONCLUSION: IC population contributes to the public health burden of HZ in England. Vaccination might be the most preferable HZ preventive measure for the IC population.

The Importance of Frailty in the Assessment of Influenza Vaccine Effectiveness Against Influenza-Related Hospitalization in Elderly People.

Background: Influenza is an important cause of morbidity and mortality among older adults. Even so, effectiveness of influenza vaccine for older adults has been reported to be lower than for younger adults, and the impact of frailty on vaccine effectiveness (VE) and outcomes is uncertain. We aimed to study VE against influenza hospitalization in older adults, focusing on the impact of frailty. Methods: We report VE of trivalent influenza vaccine (TIV) in people ≥65 years of age hospitalized during the 2011-2012 influenza season using a multicenter, prospective, test-negative case-control design. A validated frailty index (FI) was used to measure frailty. Results: Three hundred twenty cases and 564 controls (mean age, 80.6 and 78.7 years, respectively) were enrolled. Cases had higher baseline frailty than controls (P = .006). In the fully adjusted model, VE against influenza hospitalization was 58.0% (95% confidence interval [CI], 34.2%-73.2%). The contribution of frailty was important; adjusting for frailty alone yielded a VE estimate of 58.7% (95% CI, 36.2%-73.2%). VE was 77.6% among nonfrail older adults and declined as frailty increased. Conclusions: Despite commonly held views that VE is poor in older adults, we found that TIV provided good protection against influenza hospitalization in older adults who were not frail, though VE diminished as frailty increased. Clinical Trials Registration: NCT01517191.

Challenges in conducting post-authorisation safety studies (PASS): A vaccine manufacturer's view.

Post-authorisation safety studies (PASS) of vaccines assess or quantify the risk of adverse events following immunisation that were not identified or could not be estimated pre-licensure. The aim of this perspective paper is to describe the authors' experience in the design and conduct of twelve PASS that contributed to the evaluation of the benefit-risk of vaccines in real-world settings. We describe challenges and learnings from selected PASS of rotavirus, malaria, influenza, human papillomavirus and measles-mumps-rubella-varicella vaccines that assessed or identified potential or theoretical risks, which may lead to changes to risk management plans and/or to label updates. Study settings include the use of large healthcare databases and de novo data collection. PASS methodology is influenced by the background incidence of the outcome of interest, vaccine uptake, availability and quality of data sources, identification of the at-risk population and of suitable comparators, availability of validated case definitions, and the frequent need for case ascertainment in large databases. Challenges include the requirement for valid exposure and outcome data, identification of, and access to, adequate data sources, and mitigating limitations including bias and confounding. Assessing feasibility is becoming a key step to confirm that study objectives can be met in a timely manner. PASS provide critical information for regulators, public health agencies, vaccine manufacturers and ultimately, individuals. Collaborative approaches and synergistic efforts between vaccine manufacturers and key stakeholders, such as regulatory and public health agencies, are needed to facilitate access to data, and to drive optimal study design and implementation, with the aim of generating robust evidence.

Modelling estimates of the burden of respiratory syncytial virus infection in children in the UK.

OBJECTIVE: The burden of respiratory syncytial virus (RSV) illness is not well characterised in primary care. We estimated the burden of disease attributable to RSV in children in the UK between 1995 and 2009. DESIGN: Time-series regression modelling. SETTING: A multiple linear regression model based on weekly viral surveillance (RSV and influenza, Public Health England), and controlled for non-specific seasonal drivers of disease, estimated the proportion of general practitioner (GP) episodes of care (counted as first visit in a series within 28 days; Clinical Practice Research Datalink, CPRD), hospitalisations (Hospital Episode Statistics, HES) and deaths (Office of National Statistics, ONS) attributable to RSV each season. PARTICIPANTS: Children 0-17 years registered with a GP in CPRD, or with a respiratory disease outcome in the HES or ONS databases. PRIMARY OUTCOME MEASURES: RSV-attributable burden of GP episodes, hospitalisations and deaths due to respiratory disease by age. RSV-attributable burden associated with selected antibiotic prescriptions. RESULTS: RSV-attributable respiratory disease in the UK resulted in an estimated 450 158 GP episodes, 29 160 hospitalisations and 83 deaths per average season in children and adolescents, with the highest proportions in children <6 months of age (14 441/100 000 population, 4184/100 000 and 6/100 000, respectively). In an average season, there were an estimated 125 478 GP episodes for otitis media and 416 133 prescriptions for antibiotics attributable to RSV. More GP episodes, hospitalisations and deaths from respiratory disease were attributable to RSV than to influenza in children under 5 years. CONCLUSIONS: The burden of RSV in children in the UK exceeds that of influenza. RSV in children and adolescents contributes substantially to GP office visits for a diverse range of illnesses, and was associated with an average 416 133 prescribed antibiotic courses per season. Effective antiviral treatments and preventive vaccines are urgently needed for the management of RSV infection in children. TRIAL REGISTRATION NUMBER: NCT01706302.

The epidemiology of herpes zoster and its complications in Medicare cancer patients.

BACKGROUND: Literature on the epidemiology of herpes zoster (HZ) in cancer patients is sparse and does not include the elderly. The objectives of this study were to determine the incidence of HZ and related complications in elderly cancer patients and assess risk factors associated with HZ. METHODS: Patients ≥65 years diagnosed with cancer in 1991-2007 were identified from the Surveillance, Epidemiology, and End Results (SEER) cancer registry-Medicare linked database in this retrospective, longitudinal, open cohort study. The observation period spanned from first cancer diagnosis until the end of data availability. A random group of non-cancer Medicare patients served as the comparison group. Cases of HZ and related complications were ascertained from medical claims. Incidence rates (IR) and adjusted IR ratios were reported. RESULTS: The study population consisted of 82,832 hematologic (HEM) and 944,777 solid cancer patients (SOLID). During follow-up, 9.2% of HEM and 6.3% of SOLID were diagnosed with HZ. The IR of HZ was significantly higher in HEM than SOLID (31.0 vs. 14.9 per 1,000 patient-years, p <0.01). The adjusted IR ratio vs. non-cancer elderly patients was 2.4 in HEM and 1.2 in SOLID. The proportion of patients with complications was higher in HEM than SOLID (17.8% vs. 15.8%, p <0.01). Age, gender, race, certain cancer therapies, and immunosuppression were HZ risk factors. CONCLUSIONS: Elderly cancer patients run a 1.2-2.4 times higher risk of developing HZ than those without cancer. The rates of HZ and HZ-related complications are significantly higher for hematologic than solid cancer patients.