Effect of Measles Vaccination on Incidence of Measles in the Community

A study of the effect of measles vaccination on the incidence of the disease in eight separate areas of England and Wales was begun in 1966. It showed an inverse association between the proportion of children vaccinated and the incidence of measles in the area in the following year, but measles epidemics occurred in several of the areas in subsequent years, despite continuing vaccinations.Measles vaccination was introduced on a large scale in Britain in 1968. Analysis of the notification and vaccination statistics shows that the vaccination of about 10% of the child population (under 15 years) in 1968 sufficed to “replace” the measles epidemic which had been expected in the period October 1968 to September 1969 by a low incidence of the disease, typical of that in previous “interepidemic” years. Further, the effect of the vaccinations was to prevent the development of natural measles in susceptible unvaccinated children as well as in the vaccinated subjects. Thus the number of immune subjects in the community was increased by the vaccinations, but as a result there was a reduction in the number of subjects who acquired immunity from natural measles. These opposed results can therefore explain why vaccination may be effective in the community for only a year or two, though vaccination protects the individual for much longer.It is estimated that a continuing vaccination rate of 40 to 50% of the children born each year would be necessary to replace the regular biennial measles epidemics in Britain by a continuous endemic incidence, and might perhaps lead to the disappearance of the disease without a further major epidemic, but that a continuing vaccination rate of 80 to 90% of children born each year would then be necessary to prevent its reintroduction. The long-term control of measles by vaccination will thus probably prove more difficult than for any other infectious disease.     

Study of the effect of vaccination on periodic structures of measles epidemics in Japan

The purpose of this paper is to investigate the effect of vaccination on periodic structures of measles epidemics in Japan. We carried out spectral analysis for time series data of measles notifications collected in Japan. It was confirmed that the interepidemic period, which corresponds to the interval between major epidemics of measles, increases as the vaccination ratio increases. This result was supported by a theory based on a mathematical model for epidemics of infectious diseases. It was suggested that the interepidemic period is useful to estimate the effect of vaccination on measles incidences quantitatively.     

Seasonal transmission dynamics of measles in China

Measles, a highly contagious infection caused by the measles virus, is a major public health problem in China. The reported measles cases decreased dramatically from 2004 to 2012 due to the mandatory measles vaccine program started in 2005 and the goal of eliminating measles by 2012. However, after reaching its lowest level in 2012, measles has resurged again since 2013. Since the monthly data of measles cases exhibit a seasonally fluctuating pattern, based on the measles model in Earn et al. (Science 287:667–670, 2000), we propose a susceptible, exposed, infectious, and recovered model with periodic transmission rate to investigate the seasonal measles epidemics and the effect of vaccination. We calculate the basic reproduction number \({\mathcal {R}}_{0}\), analyze the dynamical behavior of the model, and use the model to simulate the monthly data of measles cases reported in China. We also carry out some sensitivity analysis of \({\mathcal {R}}_{0}\) in the terms of various model parameters which shows that measles can be controlled and eventually eradicated by increasing the immunization rate, improving the effective vaccine management, and enhancing the awareness of people about measles.     

Impact of Birth Seasonality on Dynamics of Acute Immunizing Infections in Sub-Saharan Africa

We analyze the impact of birth seasonality (seasonal oscillations in the birth rate) on the dynamics of acute, immunizing childhood infectious diseases. Previous research has explored the effect of human birth seasonality on infectious disease dynamics using parameters appropriate for the developed world. We build on this work by including in our analysis an extended range of baseline birth rates and amplitudes, which correspond to developing world settings. Additionally, our analysis accounts for seasonal forcing both in births and contact rates. We focus in particular on the dynamics of measles. In the absence of seasonal transmission rates or stochastic forcing, for typical measles epidemiological parameters, birth seasonality induces either annual or biennial epidemics. Changes in the magnitude of the birth fluctuations (birth amplitude) can induce significant changes in the size of the epidemic peaks, but have little impact on timing of disease epidemics within the year. In contrast, changes to the birth seasonality phase (location of the peak in birth amplitude within the year) significantly influence the timing of the epidemics. In the presence of seasonality in contact rates, at relatively low birth rates (20 per 1000), birth amplitude has little impact on the dynamics but does have an impact on the magnitude and timing of the epidemics. However, as the mean birth rate increases, both birth amplitude and phase play an important role in driving the dynamics of the epidemic. There are stronger effects at higher birth rates.     

The Usefulness and Feasibility of Mobile Interface in Tuberculosis Notification (MITUN) Voice Based System for Notification of Tuberculosis by Private Medical Practitioners – A Pilot Project

Introduction

Tuberculosis (TB) is a notifiable disease and health care providers are required to notify every TB case to local authorities. We conducted a pilot study to determine the usefulness and feasibility of mobile interface in TB notification (MITUN) voice based system for notification of TB cases by private medical practitioners.

Methodology

The study was conducted during September 2013 to October 2014 in three zones of Chennai, an urban setting in South India. Private clinics wherein services are provided by single private medical practitioners were approached. The steps involved in MITUN included: Registration of the practitioners and notification of TB cases by them through voice interactions. Pre and post-intervention questionnaires were administered to collect information on TB notification practices and feasibility of MITUN after an implementation period of 6 months.

Results

A total of 266 private medical practitioners were approached for the study. Of them, 184 (69%) participated in the study; of whom 11 (6%) practitioners used MITUN for TB notification. Reasons for not using MITUN include lack of time, referral of patients to government facility, issues related to patient confidentiality and technical problems. Suggestions for making mobile phone based TB notification process user-friendly included reducing call duration, including only crucial questions and using missed call or SMS options.

Conclusion

The performance (feasibility and usefulness) of MITUN voice based system for TB notification in the present format was sub-optimal. Perceived problems, logistical and practical issues preclude scale–up of notification of TB by private practitioners.     

Salivary diagnosis of measles: a study of notified cases in the United Kingdom, 1991-3.

OBJECTIVES--To validate a method for salivary diagnosis of measles and to assess the diagnostic accuracy of notified cases of measles. DESIGN--Blood and saliva samples were collected within 90 days of onset of symptoms from patients clinically diagnosed as having measles and tested for specific IgM by antibody capture radioimmunoassay. SETTING--17 districts in England and one in southern Ireland during August 1991 to February 1993. SUBJECTS--236 children and adults with measles notified by a general practitioner. RESULTS--Specific IgM was detected in serum in only 85 (36%) of the 236 cases. In cases associated with outbreaks and tested within six weeks of onset, 53/57 (93%) of samples were IgM positive, thereby confirming the sensitivity of serum IgM detection as a marker of recent infection. The serological confirmation rate was lower in cases with a documented history of vaccination (13/87; 15%) than in those without (70/149; 47%) and varied with age, being lowest in patients under a year, of whom only 4/36 (11%) were confirmed. Measles specific IgM was detected in 71/77 (92%) of adequate saliva samples collected from patients with serum positive for IgM. In cases where measles was not confirmed, 6/101 had rubella specific IgM and 5/132 had human parvovirus B19 specific IgM detected in serum. CONCLUSIONS--The existing national surveillance system for measles, which relies on clinically diagnosed cases, lacks the precision required for effective disease control. Saliva is a valid alternative to serum for IgM detection, and salivary diagnosis could play a major role in achieving measles elimination. Rubella and parvovirus B19 seem to be responsible for a minority of incorrectly diagnosed cases of measles in the United Kingdom and other infectious causes of measles-like illness need to be sought.     

Measles immunisation: results of a local programme to increase vaccine uptake.

Investigations showed that the measles immunisation programme in our health board was a failure. Surveys of health care staff and parents to determine the cause of the problem identified several aspects of concern: the immunisation of children was often left to parental initiative, with only 29% of general practitioners playing an active part in recalling children by the 15th month of age; general practitioners, clinical medical officers, paediatricians, and health visitors all required education on several aspects of measles immunisation; parents also required more information about the importance of preventing this disease. A coordinated effort to remedy these problems was introduced which achieved an increase of 13% in vaccine uptake during 1984. These findings may have implications beyond our own area.     

“They Know,They Agree,but They Don’t Do”- The Paradox of Tuberculosis Case Notification by Private Practitioners in Alappuzha District,Kerala, India

Background

Despite being a recognized standard of tuberculosis (TB) care internationally, mandatory TB case notification brings forth challenges from the private sector. Only three TB cases were notified in 2013 by private practitioners compared to 2000 TB cases notified yearly from the public sector in Alappuzha district. The study objective was to explore the knowledge, opinion and barriers regarding TB Notification among private practitioners offering TB services in Alappuzha, Kerala state, India.

Methods & Findings

This was a mixed-methods study with quantitative (survey) and qualitative components conducted between December 2013 and July 2014. The survey, using a structured questionnaire, among 169 private practitioners revealed that 88% were aware of mandatory notification. All patient-related details requested in the notification form (except government-issued identification number) were perceived to be important and easy to provide by more than 80% of practitioners. While more than 95% felt that notification should be mandatory, punitive action in case of failure to notify was considered unnecessary by almost two third. General practitioners (98%) were more likely to be aware of notification than specialists (84 %). (P<0.01). Qualitative purposive personal interviews (n=34) were carried out among private practitioners and public health providers. On thematic framework analysis of the responses, barriers to TB notification were grouped into three themes: ‘private provider misconceptions about notification’, ‘patient confidentiality, and stigma and discrimination ’and ‘lack of cohesion and coordination between public and private sector’. Private practitioners did not consider it necessary to notify TB cases treated with daily regimen.

Conclusion

Communication strategies like training, timely dissemination of information of policy changes and one-to-one dialogue with private practitioners to dispel misconceptions may enhance TB notification. Trust building strategies like providing feedback about referred cases from private sector, health personnel visit or a liaison private doctor may ensure compliance to public health activities.     

Revaccination of children during school-based measles outbreaks: potential impact of a new policy recommendation.

OBJECTIVE: To evaluate the potential impact of revaccination on measles outbreak control during school-based epidemics. DESIGN: Retrospective cohort study. SETTING: Thirty-two public elementary and high schools in 14 communities on the west island of Montreal. PARTICIPANTS: All 19,439 children attending these schools during the 1989 measles epidemic in Quebec. INTERVENTION: After notification of a case children with provider-verified records of vaccination on or after their first birthday were identified; the remaining children were vaccinated or excluded from school. OUTCOME MEASURE: Clinical or confirmed measles cases not prevented by this intervention that could have been prevented had revaccination been included during the outbreak. RESULTS: Of the 88 measles cases (74 confirmed) proof of one adequate vaccination was present in 48 (55%). Intervention generally occurred within 5 school days after case notification. The nonpreventable cases involved 75 children who had measles onset before the intervention and 11 (7 vaccinated) who had onset within 8 days after the intervention. The two remaining cases occurred 20 and 25 days after the intervention among nonvaccinated students who refused to be vaccinated. Except for these two cases measles was eliminated at every school. Application of the new Canadian guidelines for measles outbreak control would have required the administration of at least 10,000 additional doses during the outbreak to students vaccinated before 1980; implementation of the new US guidelines would have required the administration of 16,629 additional doses to children previously vaccinated only once. Well-enforced provincial regulations ensuring vaccination of every student upon school entry might have prevented 38 (43%) of the cases. The US recommendation of two routine doses of vaccine before school entry might have prevented 86 (98%) of the cases. However, revaccination during the outbreak would not have prevented a single additional case. CONCLUSION: Revaccination of previously vaccinated students during a measles outbreak would have been costly and of little benefit.     

Comparison of Respiratory Disease Prevalence among Voluntary Monitoring Systems for Pig Health and Welfare in the UK

Surveillance of animal diseases provides information essential for the protection of animal health and ultimately public health. The voluntary pig health schemes, implemented in the United Kingdom, are integrated systems which capture information on different macroscopic disease conditions detected in slaughtered pigs. Many of these conditions have been associated with a reduction in performance traits and consequent increases in production costs. The schemes are the Wholesome Pigs Scotland in Scotland, the BPEX Pig Health Scheme in England and Wales and the Pig Regen Ltd. health and welfare checks done in Northern Ireland. This report set out to compare the prevalence of four respiratory conditions (enzootic pneumonia-like lesions, pleurisy, pleuropneumonia lesions and abscesses in the lung) assessed by these three Pig Health Schemes. The seasonal variations and year trends associated with the conditions in each scheme are presented. The paper also highlights the differences in prevalence for each condition across these schemes and areas where further research is needed. A general increase in the prevalence of enzootic pneumonia like lesions was observed in Scotland, England and Wales since 2009, while a general decrease was observed in Northern Ireland over the years of the scheme. Pleurisy prevalence has increased since 2010 in all three schemes, whilst pleuropneumonia has been decreasing. Prevalence of abscesses in the lung has decreased in England, Wales and Northern Ireland but has increased in Scotland. This analysis highlights the value of surveillance schemes based on abattoir pathology monitoring of four respiratory lesions. The outputs at scheme level have significant value as indicators of endemic and emerging disease, and for producers and herd veterinarians in planning and evaluating herd health control programs when comparing individual farm results with national averages.     

Space-Time Clustering Characteristics of Tuberculosis in China, 2005-2011

Objectives

China is one of the 22 tuberculosis (TB) high-burden countries in the world. As TB is a major public health problem in China, spatial analysis could be applied to detect geographic distribution of TB clusters for targeted intervention on TB epidemics.

Methods

Spatial analysis was applied for detecting TB clusters on county-based TB notification data in the national notifiable infectious disease case reporting surveillance system from 2005 to 2011. Two indicators of TB epidemic were used including new sputum smear-positive (SS+) notification rate and total TB notification rate. Global Moran’s I by ArcGIS was used to assess whether TB clustering and its trend were significant. SaTScan software that used the retrospective space-time analysis and Possion probability model was utilized to identify geographic areas and time period of potential clusters with notification rates on county-level from 2005 to 2011.

Results

Two indicators of TB notification had presented significant spatial autocorrelation globally each year (p<0.01). Global Moran’s I of total TB notification rate had positive trend as time went by (t=6.87, p<0.01). The most likely clusters of two indicators had similar spatial distribution and size in the south-central regions of China from 2006 to 2008, and the secondary clusters in two regions: northeastern China and western China. Besides, the secondary clusters of total TB notification rate had two more large clustering centers in Inner Mongolia, Gansu and Qinghai provinces and several smaller clusters in Shanxi, Henan, Hebei and Jiangsu provinces.

Conclusion

The total TB notification cases clustered significantly in some special areas each year and the clusters trended to aggregate with time. The most-likely and secondary clusters that overlapped among two TB indicators had higher TB burden and risks of TB transmission. These were the focused geographic areas where TB control efforts should be prioritized.     

The interplay between determinism and stochasticity in childhood diseases

An important issue in the history of ecology has been the study of the relative importance of deterministic forces and processes noise in shaping the dynamics of ecological populations. We address this question by exploring the temporal dynamics of two childhood infections, measles and whooping cough, in England and Wales. We demonstrate that epidemics of whooping cough are strongly influenced by stochasticity; fully deterministic approaches cannot achieve even a qualitative fit to the observed data. In contrast, measles dynamics are extremely well explained by a deterministic model. These differences are shown to be caused by their contrasting responses to dynamical noise due to different infectious periods.     

Randomised controlled trial of the READER method of critical appraisal in general practice

Objective: To evaluate the READER model for critical reading by comparing it with a free appraisal, and to explore what factors influence different components of the model. Design: A randomised controlled trial in which two groups of general practitioners assessed three papers from the general practice section of the BMJ. Setting: Northern Ireland. Subjects: 243 general practitioners. Main outcome measures: Scores given using the READER model (Relevance, Education, Applicability, Discrimination, overall Evaluation) and scores given using a free appraisal for scientific quality and an overall total. Results: The hierarchical order for the three papers was different for the two groups, according to the total scores. Participants using the READER method (intervention group) gave a significantly lower total score (P⩽0.01) and a lower score for the scientific quality (P⩽0.0001) for all three papers. Overall more than one in five (22%), and more men than women, read more than 5 articles a month (P⩽0.05). Those who were trainers tended to read more articles (P⩽0.05), and no trainers admitted to reading none. Overall, 58% (135/234) (68% (76/112) of the intervention group) believed that taking part in the exercise would encourage them to be more critical of published articles in the future (P⩽0.01). Conclusion: Participants using the READER model gave a consistently lower overall score and applied a more appropriate appraisal to the methodology of the studies. The method was both accurate and repeatable. No intrinsic factors influenced the scores, so the model is appropriate for use by all general practitioners regardless of their seniority, location, teaching or training experience, and the number of articles they read regularly.

Key messages

• The READER method of critical appraisal is simple and easy to apply
• The method is accurate and repeatable
• General practitioners using a structured appraisal are more critical of quality
• The model may be used by general practitioners with different backgrounds, seniority, and experience of teaching and training

     

Experiences of General Practitioners and Practice Assistants during the Influenza A(H1N1) Pandemic in the Netherlands: A Cross-Sectional Survey

Objectives

Since few pandemics have occurred since the Spanish influenza pandemic, we should learn from every (mild) pandemic that occurs. The objective of this study was to report on general practitioners’ and practice assistants’ acceptance of the chosen national policy, and experiences in the Netherlands during the influenza A(H1N1)pdm09 pandemic.

Methods

Data on experience and acceptance of the chosen national policy were obtained by structured questionnaires for general practitioners (n = 372) and practice assistants (n = 503) in April 2010.

Results

The primary policy chosen for general practice was not always accepted and complied with by general practitioners, although the communication (of changes) and collaboration with involved organisations were rated as positive. In particular, the advised personal protective measures were difficult to implement in daily work and thus not executed by 44% of general practitioners. Half of the general practitioners were not satisfied with the patient information provided by the government. The influenza A(H1N1) pandemic highly impacted on general practitioners’ and practice assistants’ workloads, which was not always deemed to be adequately compensated.

Discussion

Involvement of general practitioners in future infectious disease outbreaks is essential. This study addresses issues in the pandemic policy which might be critical in a more severe pandemic.     

Ethical problems in conducting research in acute epidemics: the Pfizer meningitis study in Nigeria as an illustration

The ethics of conducting research in epidemic situations have yet to account fully for differences in the proportion and acuteness of epidemics, among other factors. While epidemics most often arise from infectious diseases, not all infectious diseases are of epidemic proportions, and not all epidemics occur acutely. These and other variations constrain the generalization of ethical decision-making and impose ethical demands on the individual researcher in a way not previously highlighted. This paper discusses a number of such constraints and impositions. It applies the ethical principles enunciated by Emmanuel et al. ¹ to the controversial Pfizer study in Nigeria in order to highlight the particular ethical concerns of acute epidemic research, and suggest ways of meeting such challenges.
The paper recommends that research during epidemics should be partly evaluated on its own merits in order to determine its ethical appropriateness to the specific situation. Snap decisions to conduct research during acute epidemics should be resisted. Community engagement, public notification and good information management are needed to promote the ethics of conducting research during acute epidemics. Individual consent is most at risk of being compromised, and every effort should be made to ensure that it is maintained and valid. Use of data safety management boards should be routine. Acute epidemics also present opportunities to enhance the social value of research and maximize its benefits to communities.
Ethical research is possible in acute epidemics, if the potential challenges are thought of ahead of time and appropriate precautions taken.     

A species distribution model for pine marten (<Emphasis Type="Italic">Martes martes</Emphasis>) in the least forested region of Europe

Species distribution modelling is a useful technique that provides data on factors that can influence a species range, identify high suitability areas and model future scenarios. The pine marten (Martes martes) has undergone major historical declines in abundance and distribution in Northern Ireland, similar to that which has occurred throughout its range. Currently, the species is in a phase of range expansion in Northern Ireland, in what is the least forested landscape in Europe. To assess the suitability of this environment for pine marten re-establishment, presence only distribution data combined with landcover data at a 10-km scale were used in a species distribution modelling study using Maxent. The results indicated that approximately 32% (4500 km²) of the land area of Northern Ireland had a high probability of pine marten occurrence. Pine marten distribution was positively associated with the extent of conifer forest landcover types, which also had the highest single attribute contribution to the model. Landcover types that were negatively associated with pine marten distribution included the extent of open, dwarf and urban areas.     

Sunlight-Exposed Biofilm Microbial Communities Are Naturally Resistant to Chernobyl Ionizing-Radiation Levels

Background

The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well.

Methodology/Principal Findings

To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta) and ascomycete fungi (Ascomycota) dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU) present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates.

Conclusions/Significance

Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in terms of general diversity patterns, despite increased mutation levels at the single-OTU level. Therefore, biofilm communities growing in sunlight exposed substrates are capable of coping with increased mutation rates and appear pre-adapted to levels of ionizing radiation in Chernobyl due to their natural adaptation to periodical desiccation and ambient UV radiation.     

Empirical determinants of measles metapopulation dynamics in England and Wales.

A key issue in metapopulation dynamics is the relative impact of internal patch dynamics and coupling between patches. This problem can be addressed by analysing large spatiotemporal data sets, recording the local and global dynamics of metapopulations. In this paper, we analyse the dynamics of measles meta-populations in a large spatiotemporal case notification data set, collected during the pre-vaccination era in England and Wales. Specifically, we use generalized linear statistical models to quantify the relative importance of local influences (birth rate and population size) and regional coupling on local epidemic dynamics. Apart from the proportional effect of local population size on case totals, the models indicate patterns of local and regional dynamic influences which depend on the current state of epidemics. Birth rate and geographic coupling are not associated with the size of major epidemics. By contrast, minor epidemics--and especially the incidence of local extinction of infection--are influenced both by birth rate and geographical coupling. Birth rate at a lag of four years provides the best fit, reflecting the delayed recruitment of susceptibles to school cohorts. A hierarchical index of spatial coupling to large centres provides the best spatial model. The model also indicates that minor epidemics and extinction patterns are more strongly influenced by this regional effect than the local impact of birth rate.     

Human birth seasonality: latitudinal gradient and interplay with childhood disease dynamics

More than a century of ecological studies have demonstrated the importance of demography in shaping spatial and temporal variation in population dynamics. Surprisingly, the impact of seasonal recruitment on infectious disease systems has received much less attention. Here, we present data encompassing 78 years of monthly natality in the USA, and reveal pronounced seasonality in birth rates, with geographical and temporal variation in both the peak birth timing and amplitude. The timing of annual birth pulses followed a latitudinal gradient, with northern states exhibiting spring/summer peaks and southern states exhibiting autumn peaks, a pattern we also observed throughout the Northern Hemisphere. Additionally, the amplitude of United States birth seasonality was more than twofold greater in southern states versus those in the north. Next, we examined the dynamical impact of birth seasonality on childhood disease incidence, using a mechanistic model of measles. Birth seasonality was found to have the potential to alter the magnitude and periodicity of epidemics, with the effect dependent on both birth peak timing and amplitude. In a simulation study, we fitted an susceptible-exposed-infected-recovered model to simulated data, and demonstrated that ignoring birth seasonality can bias the estimation of critical epidemiological parameters. Finally, we carried out statistical inference using historical measles incidence data from New York City. Our analyses did not identify the predicted systematic biases in parameter estimates. This may be owing to the well-known frequency-locking between measles epidemics and seasonal transmission rates, or may arise from substantial uncertainty in multiple model parameters and estimation stochasticity.