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Summary Objectives We assessed the association between herpes zoster (HZ) and herpes simplex (HS) occurrence whilst controlling for risk factors of HZ. Methods Using a Belgian general practitioner network, a retrospective cohort study with 3736 HZ patients and 14,076 age-gender-practice matched controls was performed, covering over 1.5 million patient-years. Multiple logistic regression was used with HZ as outcome and several diagnoses (malignancy, depression, diabetes mellitus, auto-immune diseases, asthma, multiple sclerosis, HIV, fractures), medications (systemic corticosteroids, biologicals, vaccination), HS and other infections as variables. Results HS was significantly associated with HZ for all analysed time intervals (up to five years) post HZ (OR of 3.51 [2.09 5.88] 95%CI one year post HZ) and to a lesser extent for time ranges pre HZ. Registration of other infections was significantly associated with HZ in all time intervals pre and post HZ (OR up to 1.37). Malignancy up to five years pre HZ, depression up to one year pre or post HZ, fractures up to two years pre HZ, asthma, auto-immune diseases, and immunosuppressive medication one year pre or post HZ were also associated with HZ. Conclusions HZ and HS occurrences are significantly associated and potentially share a common susceptibility beyond the known risk factors. [ABSTRACT FROM AUTHOR]

The article provides information on a study which examined key issues for health economic evaluation and modelling, applied to human papillomavirus (HPV) vaccine programs. The specific features of HPV disease and vaccination, and related policy question in the context of a literature review for economic evaluations on HPV vaccination, are outlined. It discusses the expected effect of existing HPV vaccines and cervical cancer screening. It concludes that cost-effectiveness analyses could be used in policy decisions concerning vaccines covering more HPV types, therapeutic HPV vaccines and diagnostic tests for biomarkers of HPV infection.

The article presents a study on prevaccination distribution of human papillomavirus (HPV) types in women who attended at cervical cancer screening in Belgium. It mentions than an estimate of 10,000 liquid cervical cell samples from women were examined through cytology and virology analysis with the use of primers that target E6/E7 genes from 16 HPV genes. The results show that a merely 0.1% of 9,297 treated samples were inadequate for microscopic interpretation.

Aim. To estimate the cost-effectiveness of universal childhood rotavirus vaccination in Belgium, taking into account the impact of caregiver burden and the burden of sick children for whom no medical care is sought ('no medical care'). Methods. A cohort of newborns is modeled in relation to costs and health outcomes for rotavirus disease, distinguishing episodes leading to consultations, hospitalizations, and deaths from no medical care episodes. Fully funded universal vaccination is compared with no vaccination as well as with the current situation in Belgium, whereby the 2-dose Rotarix or the 3-dose Rota-Teq vaccine can be bought at market prices, which are partially reimbursed. Results. Compared with no vaccination, fully funded universal rotavirus vaccination would cost 51,030 per quality-adjusted life year (QALY) gained with Rotarix and euro; 65,767 with RotaTeq (for society, 7572 and 30,227 per QALY, respectively). However, there is considerable uncertainty due to some analytical choices: the proportion of simulations with an acceptable incremental cost-effectiveness ratio (given a willingness to pay 50,000 for an additional QALY), increases from 2%/0.6% (Rotarix/RotaTeq) to 86%/59% when considering no medical care, and including 2 caregivers to estimate QALY loss instead of zero. Uncertainty is greater still under the societal than under the health care payer perspective. Conclusion. For the Belgian health care payer, at current vaccine prices, universal childhood rotavirus vaccination is unlikely to be judged cost-effective versus no vaccination but would be a more efficient and equitable choice than continuing with current practice. [ABSTRACT FROM AUTHOR]

The objective of this study was to model the age-time-dependent incidence of hepatitis B while estimating the impact of vaccination. While stochastic models/time-series have been used before to model hepatitis B cases in the absence of knowledge on the number of susceptibles, this paper proposed using a method that fits into the generalized additive model framework. Generalized additive models with penalized regression splines are used to exploit the underlying continuity of both age and time in a flexible non-parametric way. Based on a unique case notification dataset, we have shown that the implemented immunization programme in Bulgaria resulted in a significant decrease in incidence for infants in their first year of life with 82% (79-84%). Moreover, we have shown that conditional on an assumed baseline susceptibility percentage, a smooth force-of-infection profile can be obtained from which two local maxima were observed at ages 9 and 24 years. [ABSTRACT FROM AUTHOR]

Following the onset of the ongoing COVID-19 pandemic throughout the world, a large fraction of the global population is or has been under strict measures of physical distancing and quarantine, with many countries being in partial or full lockdown. These measures are imposed in order to reduce the spread of the disease and to lift the pressure on healthcare systems. Estimating the impact of such interventions as well as monitoring the gradual relaxing of these stringent measures is quintessential to understand how resurgence of the COVID-19 epidemic can be controlled for in the future. In this paper we use a stochastic age-structured discrete time compartmental model to describe the transmission of COVID-19 in Belgium. Our model explicitly accounts for age-structure by integrating data on social contacts to (i) assess the impact of the lockdown as implemented on March 13, 2020 on the number of new hospitalizations in Belgium; (ii) conduct a scenario analysis estimating the impact of possible exit strategies on potential future COVID-19 waves. More specifically, the aforementioned model is fitted to hospital admission data, data on the daily number of COVID-19 deaths and serial serological survey data informing the (sero)prevalence of the disease in the population while relying on a Bayesian MCMC approach. Our age-structured stochastic model describes the observed outbreak data well, both in terms of hospitalizations as well as COVID-19 related deaths in the Belgian population. Despite an extensive exploration of various projections for the future course of the epidemic, based on the impact of adherence to measures of physical distancing and a potential increase in contacts as a result of the relaxation of the stringent lockdown measures, a lot of uncertainty remains about the evolution of the epidemic in the next months. • Stochastic age-structured discrete time compartmental model • Assess the impact of the lockdown as implemented on March 13, 2020 • Conduct a scenario analysis estimating the impact of possible exit strategies • Model fitted to hospital admission, mortality and serial serological data • A lot of uncertainty remains about the evolution of the epidemic in the next months [ABSTRACT FROM AUTHOR]

Although COVID-19 has been spreading throughout Belgium since February, 2020, its spatial dynamics in Belgium remain poorly understood, partly due to the limited testing of suspected cases during the epidemic's early phase. We analyse data of COVID-19 symptoms, as self-reported in a weekly online survey, which is open to all Belgian citizens. We predict symptoms' incidence using binomial models for spatially discrete data, and we introduce these as a covariate in the spatial analysis of COVID-19 incidence, as reported by the Belgian government during the days following a survey round. The symptoms' incidence is moderately predictive of the variation in the relative risks based on the confirmed cases; exceedance probability maps of the symptoms' incidence and confirmed cases' relative risks overlap partly. We conclude that this framework can be used to detect COVID-19 clusters of substantial sizes, but it necessitates spatial information on finer scales to locate small clusters. [ABSTRACT FROM AUTHOR]

Cytomegalovirus (CMV) infection is endemic worldwide but its seroprevalence varies widely. The goal of this study was to estimate the age-specific seroprevalence of CMV infection in Belgium based on two cross-sectional serological datasets from 2002 and 2006. The seroprevalence was estimated relying on diagnostic test results based on cut-off values pre-specified by the manufacturers of the tests as well as relying on mixture models applied to continuous pathogen-specific immunoglobulin G antibody titre concentrations. The age-specific seroprevalence of hepatitis A virus (HAV), based on three Belgian cross-sectional serological datasets from 1993, 2002 and 2006, was used as a comparator since individuals acquire lifelong immunity upon recovery, implying an increasing seroprevalence with age. The age group weighted overall CMV seroprevalence derived from the mixture model was 32% (95% confidence interval (CI) 31-34%) in 2002 and 31% (95% CI 30-32%) in 2006. We demonstrated that CMV epidemiology differs from the immunizing infection HAV. This was the first large-scale study of CMV and HAV serial datasets in Belgium, estimating seroprevalence specified by age and birth cohort. [ABSTRACT FROM AUTHOR]

Background: Mathematical modelling of infectious disease is increasingly used to help guide public health policy. As directly transmitted infections, such as influenza and tuberculosis, require contact between individuals, knowledge about contact patterns is a necessary pre-requisite of accurate model predictions. Of particular interest is the potential impact of school closure as a means of controlling pandemic influenza (and potentially other pathogens).Methods: This paper uses a population-based prospective survey of mixing patterns in eight European countries to study the relative change in the basic reproduction number (R0--the average number of secondary cases from a typical primary case in a fully susceptible population) on weekdays versus weekends and during regular versus holiday periods. The relative change in R0 during holiday periods and weekends gives an indication of the impact collective school closures (and prophylactic absenteeism) may have during a pandemic.Results: Social contact patterns differ substantially when comparing weekdays to the weekend and regular to holiday periods mainly due to the reduction in work and/or school contacts. For most countries the basic reproduction number decreases from the week to weekends and regular to holiday periods by about 21% and 17%, respectively. However for other countries no significant decrease was observed.Conclusion: We use a large-scale social contact survey in eight different European countries to gain insights in the relative change in the basic reproduction number on weekdays versus weekends and during regular versus holiday periods. The resulting estimates indicate that school closure can have a substantial impact on the spread of a newly emerging infectious disease that is transmitted via close (non sexual) contacts. [ABSTRACT FROM AUTHOR]

Background: Until recently, mathematical models of person to person infectious diseases transmission had to make assumptions on transmissions enabled by personal contacts by estimating the so-called WAIFW-matrix. In order to better inform such estimates, a population based contact survey has been carried out in Belgium over the period March-May 2006. In contrast to other European surveys conducted simultaneously, each respondent recorded contacts over two days. Special attention was given to holiday periods, and respondents with large numbers of professional contacts.Methods: Participants kept a paper diary with information on their contacts over two different days. A contact was defined as a two-way conversation of at least three words in each others proximity. The contact information included the age of the contact, gender, location, duration, frequency, and whether or not touching was involved. For data analysis, we used association rules and classification trees. Weighted generalized estimating equations were used to analyze contact frequency while accounting for the correlation between contacts reported on the two different days. A contact surface, expressing the average number of contacts between persons of different ages was obtained by a bivariate smoothing approach and the relation to the so-called next-generation matrix was established.Results: People mostly mixed with people of similar age, or with their offspring, their parents and their grandparents. By imputing professional contacts, the average number of daily contacts increased from 11.84 to 15.70. The number of reported contacts depended heavily on the household size, class size for children and number of professional contacts for adults. Adults living with children had on average 2 daily contacts more than adults living without children. In the holiday period, the daily contact frequency for children and adolescents decreased with about 19% while a similar observation is made for adults in the weekend. These findings can be used to estimate the impact of school closure.Conclusion: We conducted a diary based contact survey in Belgium to gain insights in social interactions relevant to the spread of infectious diseases. The resulting contact patterns are useful to improve estimating crucial parameters for infectious disease transmission models. [ABSTRACT FROM AUTHOR]

The burden of infectious diseases is influenced by the structure of the population at risk. Population ageing may have implications for the disease burden of future epidemics. Moreover, changing household structures induced by population ageing may influence the dynamics of disease transmission and burden of infections transmitted via close contact interactions. We aim to investigate the impact of demographic change on the disease transmission dynamics and future disease burden and illustrate this for COVID-19 and influenza-like illness (ILI). We simulate the Belgian population between 2020 and 2050 using an individual-based model with census data. The simulated population structures were used as input for an infectious disease model that distinguishes between exposure to infection in the household versus exposure in the community at large. We mimicked outbreaks of COVID-19 and ILI of varying total final size. The simulated population ages between 2020 and 2050, which also affects household size and composition. As the proportion of elderly people in the population increases, the overall attack rate slightly decreases because older age groups have fewer contacts and are therefore less likely to incur and transmit infections. Despite the lower per-person attack rate, the estimated disease burden increases as morbidity and mortality increases with the age at infection. The demographic changes induced by population ageing have an impact on the burden of future outbreaks of COVID-19 and ILI in Belgium. The shifting age distribution implies that the elderly, a population group with increased morbidity and mortality in case of infection, make up an increasing proportion of the total population. Population ageing also leads to an increasing proportion of single-person households and collective households (e.g. nursing homes) in the population. Since the household attack rate varies by household size and composition, the living arrangements of the elderly population influences the disease burden of future epidemics to some extent. [ABSTRACT FROM AUTHOR]

Background Universal vaccination against rotavirus was included in the funded Australian National Immunisation Program in July 2007. Predictive cost-effectiveness models assessed the program before introduction. Methods We conducted a retrospective economic evaluation of the Australian rotavirus program using national level post-implementation data on vaccine uptake, before-after measures of program impact and published estimates of excess intussusception cases. These data were used as inputs into a multi-cohort compartmental model which assigned cost and quality of life estimates to relevant health states, adopting a healthcare payer perspective. The primary outcome was discounted cost per quality adjusted life year gained, including or excluding unspecified acute gastroenteritis (AGE) hospitalisations. Results Relative to the baseline period (1997–2006), over the 6 years (2007–2012) after implementation of the rotavirus program, we estimated that ∼77,000 hospitalisations (17,000 coded rotavirus and 60,000 unspecified AGE) and ∼3 deaths were prevented, compared with an estimated excess of 78 cases of intussusception. Approximately 90% of hospitalisations prevented were in children <5 years, with evidence of herd protection in older age groups. The program was cost-saving when observed changes (declines) in both hospitalisations coded as rotavirus and as unspecified AGE were attributed to the rotavirus vaccine program. The adverse impact of estimated excess cases of intussusception was far outweighed by the benefits of the program. Conclusion The inclusion of herd impact and declines in unspecified AGE hospitalisations resulted in the value for money achieved by the Australian rotavirus immunisation program being substantially greater than predicted by pre-implementation models, despite the potential increased cases of intussusception. This Australian experience is likely to be relevant to high-income countries yet to implement rotavirus vaccination programs. [ABSTRACT FROM AUTHOR]

This study assessed the costs and benefits of introducing routine varicella vaccination to healthy children in Germany. Three vaccination strategies were compared with that of no prevention: vaccination of all 15-month-old children; vaccination of susceptible 12-year-olds (adolescent); and a combination of strategies (children including catch-up). From a purely economic viewpoint, the adolescent strategy was optimal: It was the only one that resulted in net direct cost savings. However, since this strategy may be less acceptable from a medical or organizational point of view and because total net savings were the highest, a second option was to begin immunization starting with the 15month-old children and to use the catch-up strategy for 11 years (total benefit-to-cost ratio (BCR), 4.72:1; cost-effectiveness ratio (CER), OM 6915 per life-year saved) and from year 12 on to use the first strategy (BCR, 4.60:1; CER, DM 19,735 per life-year saved). [ABSTRACT FROM PUBLISHER]

Background Few studies about health-related quality of life ( HRQoL) in patients with melanoma have expressed their results in terms of utilities or disability weights ( DWs). Utilities are required for calculating quality-adjusted life years and therefore for cost-effectiveness analyses. DWs are useful to assess the burden of diseases through disability-adjusted life years. Objectives To provide utilities and DWs regarding patients with melanoma. Methods The patients were classified into eight groups using four stages based on the 2009 American Joint Committee on Cancer stages, with each stage subdivided into treatment and remission phases. The EuroQoL Five Dimensions Five Levels ( EQ-5D-5L) questionnaire was completed by the patients with melanoma to provide a mean utility for each group. In addition to this, the EuroQoL visual analogue scale ( VAS) and a validated quality-of-life questionnaire dedicated to patients with melanoma [Functional Assessment of Cancer Therapy Melanoma ( FACT-M)] were completed by the same patients in order to compare their results with the obtained utilities. DWs were obtained by calculating, for each patient, the difference between his/her utility and the corresponding sex- and age-specific population norm. Results A total of 395 questionnaire sets were completed. Utilities and DWs showed significant differences between follow-up groups. Treatment groups had similar utilities and DWs but these results were obtained during different treatment durations and therefore have different weights. The VAS and the FACT-M were found to be less sensitive. Nevertheless, the FACT-M identified some problems not found by the EQ-5D-5L questionnaire. Conclusions The EQ-5D-5L questionnaire seems adequate to provide utilities and DWs in patients with melanoma. Lower HRQoL in female patients with melanoma is probably linked to lower HRQoL in the general population. [ABSTRACT FROM AUTHOR]