Manas K. Akmatov

Social contacts of school children and the transmission of respiratory-spread pathogens

Empirical data about contact frequencies of children is needed for estimating parameters in mathematical modelling studies that investigate the effect of targeting influenza intervention to children. A survey about the social contacts of school children was conducted in a primary school in Germany. The distribution of the daily numbers of contacts was stratified by age of the contacted person and by weekday. A negative binomial regression analysis was performed to investigate factors that influence contact behaviour. Using logistic regression analysis we examined the relationship between the numbers of private contacts and having been ill in the last 6 months. We computed effective contact numbers to take the heterogeneity in contact behaviour into account in assessing the contribution of childrens contacts to the overall transmission of an infection. The possible effects of intervention measures such as school closure and vaccination on the transmission of respiratory-spread agents to other age groups are discussed.

Timeliness of vaccination and its effects on fraction of vaccinated population

Delayed vaccination against childhood diseases may lead to increased mortality and morbidity among children and also affect the fraction of vaccinated population necessary for elimination of a disease. The purpose of this study was to assess the extent of the delay in vaccinations in four countries belonging to Commonwealth of Independent States and to assess how the timeliness of vaccination affects the vaccination coverage. The fraction of children vaccinated with delay was substantial in all the studied countries, and the impact of differences between countries was stronger than individual risk factors assessed in this study. In presence of vaccination delay, up-to-date vaccination is a biased estimator of the fraction of vaccinated population. Age-appropriate vaccination should be taken into account when assessing vaccination coverage.

Timeliness of childhood vaccinations in 31 low and middle-income countries

Background This study assessed the extent of delays in childhood vaccinations and examined sociodemographic correlates of delayed and missing vaccinations. Methods Datasets from the 2005–7 Multiple Indicator Cluster Surveys from 31 countries were used. Information on vaccinations was based on vaccination cards. Survival analysis was applied to assess age-specific vaccination rates, and multilevel logistic regression analysis was used to assess factors associated with delayed and missing vaccinations. Results The median vaccination coverage across all countries varied from 91% measles-containing vaccine (MCV) to 98% bacille Calmette–Guérin vaccine (BCG). The median fraction of timely administered vaccinations was 65% (range 14.5–97.2%) for BCG, 67% (11.6–89.3%) for the first dose of vaccine against diphtheria, tetanus and pertussis (DTP1), 41% (10.8–82.1%) for DTP3, 68% (29.7–90.3%) for the first dose of polio vaccine (polio1), 38% (10.5–81.0%) for polio3 and 51% (22.3–91.1%) for MCV. The median of the median delays across all countries was 2.1 weeks (IQR 0.9–3.0) for BCG, 2.4 weeks (1.5–3.1) for DTP1; 6.3 weeks (3.3–9.0) for DTP3; 2.0 weeks (1.3–3.1) for polio1, 6.6 weeks (4.3–9.3) for polio3 and 4.1 weeks (2.5–5.8) for MCV. A higher number of children in households and lower socioeconomic status were associated with delayed and missing vaccinations; however, the effects of socioeconomic gradient varied by country. Conclusion Most countries achieved high up-to-date vaccination coverage. However, there were substantial vaccination delays. Collecting information on the timeliness of vaccination in national surveillance systems will provide a more complete view of vaccination coverage. Missing and delayed vaccinations can be addressed jointly in prevention programmes.

Changing epidemiology of Hepatitis B and migration—a comparison of six Northern and North-Western European countries

BACKGROUND Increased migration volume and different Hepatitis B prevalence between immigration and emigration countries have changed the Hepatitis B virus (HBV) epidemiology considerably in Northern and North-Western European migrants-receiving countries. Due to the difference in migration status monitoring, the HBV infection data on migrants are not easily comparable among those countries. The study aims were: to compare the migration status indicators used by the national surveillance system in six Northern and North-Western European countries (the Netherlands, Germany, Finland, Denmark, Sweden and the UK); to determine the impact of the migration status on HBV infection by comparing the available data on prevalence and transmission routes of Hepatitis B in the migration and the general population in the six countries; to recommend sensible indicators and pertinent measures for HBV infection surveillance and control in the region. METHODS Literature review, statistical data analysis on migration and HBV infection in the six countries; expert interviews to identify migration status indicators used in national surveillance systems. RESULTS Evident differences were found between the migration and the general population in Hepatitis B prevalence and transmission routes in the six countries. Migration status is monitored differently in six surveillance systems; immigrants from high/intermediate Hepatitis B endemic countries constitute a substantial proportion of HBsAg(+) and chronic cases in all six countries. CONCLUSIONS International migration has an obvious impact on Hepatitis B prevalence in the six countries. It is important to include common migration status indicators and to collect comparable data for HBV infection surveillance in different notification systems.

Methicillin-sensitive and methicillin-resistant Staphylococcus aureus nasal carriage in a random sample of non-hospitalized adult population in northern Germany.

Objective The findings from truly randomized community-based studies on Staphylococcus aureus nasal colonization are scarce. Therefore we have examined point prevalence and risk factors of S. aureus nasal carriage in a non-hospitalized population of Braunschweig, northern Germany. Methods A total of 2026 potential participants were randomly selected through the residents registration office and invited by mail. They were requested to collect a nasal swab at home and return it by mail. S. aureus was identified by culture and PCR. Logistic regression was used to determine risk factors of S. aureus carriage. Results Among the invitees, 405 individuals agreed to participate and 389 provided complete data which was included in the analysis. The median age of the participants was 49 years (IQR: 39–61) and 61% were females. S. aureus was isolated in 85 (21.9%; 95% CI: 18.0–26.2%) of the samples, five of which were MRSA (1.29%; 95% CI: 0.55–2.98%). In multiple logistic regression, male sex (OR = 3.50; 95% CI: 2.01–6.11) and presence of allergies (OR = 2.43; 95% CI: 1.39–4.24) were found to be associated with S. aureus nasal carriage. Fifty five different spa types were found, that clustered into nine distinct groups. MRSA belonged to the hospital-associated spa types t032 and t025 (corresponds to MLST CC 22), whereas MSSA spa types varied and mostly belonged to spa-CC 012 (corresponds to MLST CC 30), and spa-CC 084 (corresponds to MLST CC 15). Conclusion This first point prevalence study of S. aureus in a non-hospitalized population of Germany revealed prevalence, consistent with other European countries and supports previous findings on male sex and allergies as risk factors of S. aureus carriage. The detection of hospital-associated MRSA spa types in the community indicates possible spread of these strains from hospitals into the community.

Factors associated with wife beating in Egypt: Analysis of two surveys (1995 and 2005)

BackgroundWife beating is an important public health problem in many developing countries. We assessed the rates of wife beating and examined factors associated with wife beating in 1995 and 2005 in Egypt.MethodsWe used data from two Demographic and Health Surveys (DHS) conducted in Egypt in 1995 and 2005 using multistage household sampling. Data related to wife beating included information from 7122 women in 1995 and 5612 women in 2005. Logistic regression was used to analyze factors independently associated with wife beating. Special weights were used to obtain nationally representative estimates.ResultsIn 1995 17.5% of married women in Egypt experienced wife beating in the last 12 months, in 2005 – 18.9% or 16.0%, using different measures. The association between socio-demographic differentials and wife beating was weaker in the newer survey. The 12-month prevalence of wife beating was lower only when both partners were educated, but the differences across education levels were less pronounced in 2005. Based on the information available in the 2005 survey, more educated women experienced less severe forms of wife beating than less educated women.ConclusionDifferent measures used in both surveys make a direct comparison difficult. The observed patterns indicate that the changes in prevalence may be masked by two opposite processes occurring in the society: a decrease in (severe forms of) wife beating and an increase in reporting of wife beating. Improving the access to education for women and raising education levels in the whole society may help reducing wife beating.

Equivalence of self- and staff-collected nasal swabs for the detection of viral respiratory pathogens.

Background The need for the timely collection of diagnostic biosamples during symptomatic episodes represents a major obstacle to large-scale studies on acute respiratory infection (ARI) epidemiology. This may be circumvented by having the participants collect their own nasal swabs. We compared self- and staff-collected swabs in terms of swabbing quality and detection of viral respiratory pathogens. Methodology/Principal Findings We conducted a prospective study among employees of our institution during the ARI season 2010/2011 (December-March). Weekly emails were sent to the participants (n = 84), reminding them to come to the study center in case of new symptoms. The participants self-collected an anterior nasal swab from one nostril, and trained study personnel collected one from the other nostril. The participants self-collected another two swabs (one from each nostril) on a subsequent day. Human β-actin DNA concentration was determined in the swabs as a quality control. Viral respiratory pathogens were detected by multiplex RT-PCR (Seeplex RV15 kit, Seegene, Eschborn, Germany). Of 84 participants, 56 (67%) reported at least one ARI episode, 18 participants two, and one participant three. Self-swabbing was highly accepted by the participants. The amount of β-actin DNA per swab was higher in the self- than in the staff-collected swabs (p = 0.008). β-actin concentration was lower in the self-swabs collected on day 1 than in those collected on a subsequent day (p<0.0001). A respiratory viral pathogen was detected in 31% (23/75) of staff- and in 35% (26/75) of self-collected swabs (p = 0.36). With both approaches, the most frequently identified pathogens were human rhinoviruses A/B/C (12/75 swabs, 16%) and human coronavirus OC43 (4/75 swabs, 5%). There was almost perfect agreement between self- and staff-collected swabs in terms of pathogen detection (agreement = 93%, kappa = 0.85, p<0.0001). Conclusions/Significance Nasal self-swabbing for identification of viral ARI pathogens proved to be equivalent to staff-swabbing in this population in terms of acceptance and pathogen detection.

Principles of Infectious Disease Epidemiology

In this chapter, principles and concepts of modern infectious disease epidemiology Epidemiology are presented. We delineate the role of epidemiology for public health and discuss the characteristics of infectious disease epidemiology. This chapter also includes definitions of important terms used in infectious disease epidemiology.

E-mail-based symptomatic surveillance combined with self-collection of nasal swabs: a new tool for acute respiratory infection epidemiology

Summary Objective We examined the feasibility of combining communication by e-mail and self-collection of nasal swabs for the prospective detection of acute respiratory infections in a non-medical setting. Methods The study was conducted among a convenience sample of employees (n =53) at a research institution (December 2009–April 2010). Real-time data on the occurrence of acute respiratory symptoms and a nasal self-swab were collected prospectively, with automated weekly e-mails as a reminder mechanism. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect respiratory viral pathogens in the swabs. Results Fifty-one out of 53 participants completed the study. The study design was well accepted. Thirty (∼57%) participants reported at least one episode of acute respiratory infection and returned the nasal swab during the study period (eight participants reported two episodes). The majority had no difficulties taking the self-swab and preferred this to swabbing by study personnel. Most participants obtained and returned the swabs within the recommended time. Viral respiratory pathogens were detected in 19 of 38 swabs (50%), with coronaviruses 229E/NL63 and OC43 and rhinoviruses A and B constituting 17 positive swabs (89%). Conclusions Combining e-mail-based symptomatic surveillance with nasal self-swabbing promises to be a powerful tool for the real-time identification of incident cases of acute respiratory infections and the associated pathogens in population-based studies.

Identification of broadly discriminatory tissue biomarkers of synovitis with binary and multicategory receiver operating characteristic analysis

Immunohistochemical synovial tissue biomarkers are used increasingly to classify arthropathies, study their pathogenesis, and to measure disease activity in clinical trials. We have used receiver operating characteristic (ROC) analysis to quantify the discriminatory abilities of markers for common inflammatory cells (subintimal CD15, CD68, CD3, CD20, CD38, and lining CD68), proliferating cells (Ki-67) and blood vessels (von Willebrand factor, vWF) among inflammatory (chronic septic arthritis, early arthritis and rheumatoid arthritis (RA)) and degenerative arthropathies (osteoarthritis (OA) and orthopedic arthropathies) and normal synovium. Six of the eight markers distinguished accurately between RA and the degenerative arthropathies (area under the curve (AUC) 0.91–0.97), whereas subintimal CD68 (AUC 0.92) and Ki-67 (AUC 0.87) distinguished best between OA and normal synovium. Fold differences in mean expression correlated only modestly with AUCs (r2 = 0.44). Multicategory ROC analysis ranked Ki-67, subintimal CD68, and CD15 as discriminating best among all six sample groups, and thus identified them as the most broadly applicable markers.