Antibody titers against measles, rubella, mumps and varicella-zoster viruses in medical students]

It is important to identify and immunize susceptible students who have clinical practice to prevent and control hospital infections. The antibody titers to measles, rubella, mumps and varicella viruses were measured in 1,139 students(417 men, 722 women, average age 21.3+/-2.7 yr old)including 510 medical students, 442 nursing students and 187 students of the School of Medical Technology in Kurume University. Antibodies against measles virus were detected by particle agglutination assay(PA), those against rubella virus by hemagglutination inhibition assay(HI), and those against mumps and varicella viruses by enzyme-linked immunosorbent assay(EIA). The serological susceptibilities to measles, rubella, mumps and varicella viruses were 112(9.8%), 112(9.8%), 163(14.3%)and 73(6.4%), respectively. The serological susceptibilities to measles, rubella and mumps viruses in male students were not different from those in female students. The susceptibility to varicella virus in female students was significantly higher than that in male students. After susceptible students were recommended to have vaccinations against each virus, the vaccination rate of the students without antibody was 99.1%. The history of infection and vaccination against the viruses were examined by self-recorded questionnaires in 406 students from all disciplines. The serological susceptibility of students with positive vaccination history was 11.1% for measles, 6.8% for rubella, 18.3% for mumps, and 4.9% for varicella. The serological susceptibility of students with a positive infection history was 5.7% for measles, 3.4% for rubella, 2.9% for mumps, and 4.9% for varicella. In the self-recorded questionnaire, the rate of unknown infection and vaccination histories were 57.5% and 71.6% for measles, 52.5% and 68.4% for rubella, 34.3% and 75.6% for mumps, and 27.1% and 80.5% for varicella, respectively. In conclusion, these data confirm that it is essential to assess immune status against measles, rubella, mumps and varicella in students who have clinical practice in hospital regardless of infection or vaccination history. Accordingly, susceptible students should be vaccinated to prevent those viral infections in hospital.     

Modelling rubella in Europe

The prevention of congenital rubella syndrome (CRS), as a complication of rubella infection during pregnancy, is the main aim of rubella vaccination programmes. However, as vaccination of infants leads to an increase in the average age at which those who were not immunized become infected, certain rubella vaccination programmes can lead to an increase in the incidence of CRS. In this paper we use a mathematical model of the transmission dynamics of rubella virus to investigate the likely impact of different vaccination policies in Europe. The model was able to capture pre- and post-vaccination patterns of infection and prevalence of serological markers under a wide variety of scenarios, suggesting that the model structure and parameter estimates were appropriate. Analytical and numerical results suggest that endemic circulation of rubella is unlikely in Finland, the United Kingdom, The Netherlands, and perhaps Denmark, provided vaccine coverage is uniform across geographical and social groups. In Italy and Germany vaccine coverage in infancy has not been sufficient to interrupt rubella transmission, and continued epidemics of CRS seem probable. It seems unlikely that the immunization programmes in these countries are doing more harm than good, but this may be partly as a result of selective immunization of schoolgirls. Indeed, in both these countries, selective vaccination of schoolgirls with inadequate vaccination histories is likely to be an important mechanism by which CRS incidence is suppressed (unlike the other countries, which have had sufficiently high infant coverage rates to withdraw this option). Reducing inequalities in the uptake of rubella vaccine may bring greater health benefits than increasing the mean level of coverage.     

Antibody persistence in children aged 6–7 years one year following booster immunization with two MMR vaccines applied by aerosol or by injection

ImportanceIn a previous study on booster vaccination, we reported that two aerosolized MMR vaccines were as safe and immunogenic as injectable vaccines containing the same antigens. We now present results of antibody persistence one year after immunization.ObjectiveTo assess the antibody persistence for measles, mumps, and rubella one year following booster immunization.MethodsWe performed clinical and serological follow-up of participants in a previous study of Mexican children aged 6–7 years, in which participants were randomized to four groups receiving, by aerosolized or by injection, the MMR SII vaccine (Serum Institute of India), or the MMR II (Merck Sharp & Dhome). We evaluated the antibody persistence by PRN test for measles and by ELISA for rubella and mumps. The occurrence of clinical events was evaluated via periodic visits of a nurse team to children’s schools and homes.ResultsOf the 260 initial participants, 241 completed one-year follow-up. There were only statistically significant differences in baseline seropositivity for mumps. One year after immunization, seropositivity in all groups was 100% for measles and rubella. The seropositivity rank for mumps was from 90.3% for the injected vaccine MMR II to 96.6% for vaccine MMR SII applied by aerosol; these differences were not statistically significant. With exception of the aerosolized vaccine MMR SII for the geometric mean titer (GMT) for measles, all study groups presented declination of GMT for the three viruses. The difference between the aerosolized vaccines MMR SII and MMR RII was statistically significant for mumps antibodies. Only mild clinical events were identified.ConclusionUnder conditions of no endemic transmission for measles and rubella, and of low circulation of mumps virus, school-aged children remained seropositive to the three viruses one year following booster immunization.The study was registered under CMN 2010-005 number at COFEPRIS (National Regulatory Authority).     

Seroprevalence of measles,mumps and rubella among children in American Samoa, 2011, and progress towards West Pacific Region goals of elimination

Introduction

In line with the global goals for measles elimination, countries in the West Pacific Region (WPR) have set a goal to eliminate measles by 2012. Due to its contagiousness, high population immunity is needed for achieving and documenting measles elimination. We assessed population immunity to measles, mumps and rubella among first grade children in American Samoa (AS) through a seroprevalance study.

Methods

Using commercial indirect enzyme-linked immunosorbant IgG assays (Wampole Laboratories, Cranbury, NJ) we determined IgG antibodies against the measles, mumps, and rubella (MMR) viruses in sera collected from first grade students in AS in April–May 2011. Vaccination status was retrieved from the immunization cards. Factors associated with seropositivity of measles, mumps, and rubella were analyzed separately.

Result

Among 509 first grade students, measles, mumps, and rubella seroprevalence were 92%, 90%, and 93%, respectively. The proportions of first grade students with documented one or two doses of MMR vaccine were 93% and 84%, respectively. The vaccination status of 6% of the first graders was unknown and 1% was unvaccinated. Receiving two-doses of MMR vaccines was associated with high measles and mumps seropositivity (p < 0.01).

Conclusion

The high measles seroprevalence among children shows the progress by American Samoa towards measles elimination. Achieving and maintaining high two-dose MMR vaccine coverage in all age groups will aid in attaining the measles elimination status and prevent transmission of measles from potential imported measles cases from other countries.     

Estimating vaccination coverage for the trivalent measles-mumps-rubella vaccine from trivariate serological data

The effectiveness of childhood immunization programs depends on the vaccination coverage actually achieved. Routinely collected coverage data are not always available, and comparability between countries is often compromised because of different data collection methods. In 2000, Gay developed a method to estimate trivalent vaccination coverage from readily available trivariate serological data on the basis of parametric assumptions related to the rate of seroconversion for each vaccine component and probabilities of natural exposure to infection. Gay's work was indirectly published in a paper by Altmann and Altmann, who derived exact solutions for the parameters on the basis of Gay's modeling equations. In this paper, we propose a general likelihood‐based marginal model framework to extend Gay's model by relaxing two of its main assumptions. We use the Bahadur model for trivariate binary data to explicitly account for an association between the disease‐specific exposure probabilities. We fit several correlation structures to measles, mumps, and rubella serology from Belgium and Ireland. For both countries, we estimate a small positive pairwise exposure correlation, which improves the fit to the data. However, the effect on the estimated vaccination coverage and its associated variability is fairly moderate. For both Belgium and Ireland, all models reveal that the vaccination coverage achieved during the first 15 years since the introduction of measles, mumps, and rubella immunization is insufficient to eliminate measles. Copyright © 2012 John Wiley & Sons, Ltd.     

天津市麻疹风疹及流行性腮腺炎抗体水平分析

目的了解天津市健康人群麻疹、风疹、流行性腮腺炎抗体水平,评价疫苗接种需求。方法2007年3月采集0~57岁健康人群608人份血样品,用ELISA方法定量检测麻疹、风疹、流行性腮腺炎IgG抗体水平。运用直线相关分析抗体阳性率,保护率GMC与疾病发病率之间的关系,P0.05为差异有统计学意义。结果麻疹、风疹和流行性腮腺炎疫苗接种率分别为70.39%、16.78%和12.34%;抗体阳性率分别为91.78%,65.79%和73.52%;抗体几何平均浓度(GMC)分别为2 488.10 IU/L、200.4 IU/ml和759.91 U/ml。麻疹抗体阳性率,保护率与发病率存在明显相关关系(P0.01),而GMC与麻疹发病率没有显著性相关;风疹和流行性腮腺炎抗体阳性率、GMC与发病率无相关关系。结论本次调查显示2007年天津市麻疹人群抗体GMC总体保持在较高水平。风疹、流行性腮腺炎疫苗接种率和抗体水平较低,2剂次的麻腮风疫苗(MMR)纳入免疫规划既有助于消除麻疹,也有利于控制风疹和流行性腮腺炎。     

Seroprevalence and immunization history of selected vaccine preventable diseases in medical students

To evaluate protection against vaccine-preventable diseases in medical students, we obtained data on immunization status and history of diphtheria, tetanus, pertussis, poliomyelitis, measles, mumps, rubella, varicella and hepatitis B from students with elective periods in our institution. Further, serum antibodies against measles, mumps, rubella and varicella-zoster virus (VZV) and hepatitis B surface (HBs) antigen were determined on a voluntary basis. For students with incomplete immunization status or lack of protective antibodies, vaccination was offered for free. Success of catch-up immunizations was serologically confirmed 4 weeks later. From May 1999 to April 2003, 170 students were enrolled; their mean age was 26 years with a median of 25 years (range 22-48 years). Immunization records were complete in 148 (87%), incomplete in 11 (6.5%) and missing in 11 (6.5%) students. Only 26% of the cohort had a complete and up-to-date immunization status. Seroprevalence of IgG antibodies against measles, mumps, rubella, VZV and HBs (> or = 10 IU/l) in 149 students were 85, 85, 92, 97 and 90%, respectively. Indications for > or = 1 catch-up immunization were found in 125 (74%) students and were accepted by 97 of them (78%). Sixty two (99%) of 63 immunized students available for follow-up demonstrated an adequate serological response. In conclusion, the great majority of medical students had immunization gaps. Systematic immunization programmes for medical students should be implemented.     

Immune response after primary and re-vaccination with different combined vaccines against measles, mumps, rubella

The humoral immune response after primary and re-vaccination confirmed the high immunogenicity of the combined vaccines used: "MMR-Vax(R)", "Pluserix(R)" and "Triviraten(R)". The investigation of paired serum samples of prevaccinal seronegative infants (n90-100% for all three components with the exception of the mumps component of "Triviraten(R)" (38%). However, by additional methods (plaque neutralisation test, immunofluorescence test) mumps antibodies could be detected in 93.4% of infants having received vaccine "Triviraten(R)". The mean values of antibody activities against the three components did not differ significantly after vaccination with "MMR-Vax(R)" and "Pluserix(R)". However, after vaccination with "Triviraten(R)" the mean antibody values were significantly lower (P<0.01) against the measles strain "Edmonston-Zagreb" and especially lower (2-20 times) against the mumps virus strain "Rubini". Revaccination of pre-vaccinal seropositive schoolchildren and adolescents (n=676) with "MMR-Vax(R)" and "Pluserix(R)" produced no different results. The rate of vaccinees responding with a booster reaction reached 68.4% for measles and mumps, but only 8.6% for rubella. A booster reaction could be observed in 100% of those vaccinees who had antibodies at a low level, also in the case of naturally acquired immunity. The low-level range for antibodies against measles was defined as 0.15<0. 40 IU/ml, mumps 1:230相似文献   

Immunity against infectious diseases: predictive value of self-reported history of vaccination and disease.

OBJECTIVE: To determine whether self-reported history of disease and/or vaccination is predictive of immunity against hepatitis B, varicella, rubella, mumps, and measles. DESIGN: The seroprevalence of viral antibodies and the predictive value of a self-report questionnaire were determined for 616 paramedical students who matriculated into Padua Medical School (Padua, Italy) during 2003-2005. RESULTS: The majority of subjects (86.9%) remembered being vaccinated against hepatitis B but had no recollection of disease. Among vaccinees, 1.5% showed markers of previous infection, 6.7% tested negative for anti-hepatitis B virus surface antigen (anti-HBsAg) antibodies, and 91.8% tested positive for anti-HBsAg. Self-reported vaccination history had a positive predictive value of 93.2% for test results positive for immunity against hepatitis B. Immunity against varicella (93.7% of subjects) and rubella (95.5%) was high, compared with immunity against mumps (79.9%) and measles (83.1%). In addition, results of tests for detection of immunity against mumps and measles were equivocal for more than 7% of subjects, probably because their vaccination regimen was not completed. Self-reported histories of varicella disease and rubella disease and vaccination had high positive predictive values (greater than 98% each) for testing positive for antiviral antibodies, compared with self-reported histories of mumps disease and vaccination and measles disease and vaccination; however, high positive predictive values were observed for self-reported histories of mumps only (92.0%) and measles only (94.7%). CONCLUSIONS: The self-report questionnaire used in this study did not accurately predict immunity against 5 transmittable but vaccine-preventable diseases. A complete serological evaluation of healthcare workers, followed by vaccination of those with negative or equivocal results of serological tests, is an appropriate measure to decrease the risk of infection in this population.     

Interpreting serological surveys using mixture models: the seroepidemiology of measles, mumps and rubella in England and Wales at the beginning of the 21st century

A mixture modelling technique is applied to age-specific frequency distributions of quantitative results from serological surveys for measles, mumps and rubella using samples collected across the age range in England and Wales in 2000. In accordance with previous studies the analysis suggests that the antibody response to natural infection is stronger than that produced by vaccination, that vaccine-induced antibody levels wane with time and that levels of vaccine-induced antibody response vary for each virus infection being strongest for rubella and weakest for mumps. The current mumps epidemic in the United Kingdom is focused in cohorts born during 1982-1987 who were too old to have received routine MMR vaccination. In the cohort born in 1981-1985 the model estimates that 7.5% have no evidence of mumps specific IgG and 24.9% have the lowest level of detectable antibody. The similar proportions of mumps antibody in these categories among cohorts with opportunity for 1 or 2 doses of vaccine is a concern, as the degree to which these individuals are protected is unclear. Investigations into the efficacy of two doses of a mumps containing vaccine should be a priority during the current epidemic.     

Seroprevalence of Antibodies to Measles, Mumps, and Rubella among Thai Population: Evaluation of Measles/MMR Immunization Programme

Stored serum specimens, from four regions of Thailand, of healthy children attending well baby clinics and of healthy people with acute illnesses visiting outpatient clinics were randomly sampled and tested for IgG antibody to measles, mumps, and rubella (MMR). The immunity patterns of rubella and mumps fitted well with the history of rubella and MMR vaccination, seroprotective rates being over 85% among those aged over seven years. A high proportion of younger children acquired the infection before the age of vaccination. MMR vaccination should preferably be given to children at an earlier age. For measles, 73% seroprotective rates among children, aged 8-14 years, who should have received two doses of measles/MMR vaccine, were lower than expected. This finding was consistent with the age-group reported in outbreaks of measles in Thailand. The apparent ineffectiveness (in relation to measles) of MMR immunization of 1^st grade students warrants further studies.Key words: Antibodies, Immunization, Measles, Measles vaccine, Mumps, MMR vaccine, Rubella, Seroepidemiologic studies, Seroprevalence, Vaccination, Thailand     

Seroprotection to vaccine‐preventable diseases among workers at a Victorian tertiary hospital

Objective : To determine seroprotection for the vaccine‐preventable diseases (VPDs) measles, mumps, rubella, varicella and hepatitis B among new employees seen at a Victorian tertiary hospital staff clinic. Methods : Employees who presented to the staff clinic for immunisation assessment between 1 January 2012 and 31 December 2013 were included. Demographic data, self‐reported disease history and previous vaccination status were reviewed retrospectively to determine impact on serological results. Results : A total of 1,901 new employees were included, 83% of whom were at risk of direct contact with blood or body substances. Overall, the proportion of workers seropositive to measles was 88%, mumps 90%, rubella 78%, varicella 93% and hepatitis B 80%. Staff born before 1966 were more likely to have positive measles or mumps serology but negative rubella or hepatitis B serology (p<0.05 for each). Staff who self‐reported measles (99% vs. 93%, p=0.03) or varicella infection (98% vs. 92%, p<0.001) were more likely to be seropositive, but those reporting previous vaccination to measles, mumps or rubella were no more likely to be seropositive. Conclusions and implications : This study demonstrated levels of seropositivity of 78–93% for the five VPDs. Despite recognised limitations of serological testing, 10–20% of new employees to a healthcare institution lacking seroprotection represents a potentially unacceptable risk of nosocomial transmission of these VPDs. Our findings support ongoing serological testing of new healthcare staff at risk of direct contact with blood or body substances.     

Using models to shape measles control and elimination strategies in low- and middle-income countries: A review of recent applications

After many decades of vaccination, measles epidemiology varies greatly between and within countries. National immunization programs are therefore encouraged to conduct regular situation analyses and to leverage models to adapt interventions to local needs. Here, we review applications of models to develop locally tailored interventions to support control and elimination efforts. In general, statistical and semi-mechanistic transmission models can be used to synthesize information from vaccination coverage, measles incidence, demographic, and/or serological data, offering a means to estimate the spatial and age-specific distribution of measles susceptibility. These estimates complete the picture provided by vaccination coverage alone, by accounting for natural immunity. Dynamic transmission models can then be used to evaluate the relative impact of candidate interventions for measles control and elimination and the expected future epidemiology. In most countries, models predict substantial numbers of susceptible individuals outside the age range of routine vaccination, which affects outbreak risk and necessitates additional intervention to achieve elimination. More effective use of models to inform both vaccination program planning and evaluation requires the development of training to enhance broader understanding of models and where feasible, building capacity for modelling in-country, pipelines for rapid evaluation of model predictions using surveillance data, and clear protocols for incorporating model results into decision-making.     

Increase of vaccination coverage by mass media and individual approach: intensified measles, mumps, and rubella prevention program in Finland

In the 1970s, mass vaccination projects were started in various parts of the world against measles and congenital rubella, with eradication as the final goal. In many developing and industrial countries, including Finland, the elimination of measles failed because of low vaccination coverage. In Finland, a combined measles, mumps, and rubella (Virivac) vaccination program was started in 1982. Computerized recording of the vaccinated children was considered necessary and was integrated with the population registry to identify the hard-to-reach families. Several interventions improved compliance: a mass media campaign and notification of nonvaccinated children to local health professionals and parents. All successive campaigns increased vaccination coverage significantly, with the notification of parents about their nonvaccinated child being especially effective. A vaccination coverage of over 96% was achieved, which theoretically prevents measles, mumps, and rubella transmission.     

预防接种对南京市鼓楼区流行性腮腺炎流行病学特征的影晌

目的掌握南京市鼓楼区流行性腮腺炎（流腮）的发病规律,评估预防接种前后21年流腮的流行病学特征变化。方法对南京市鼓楼区1991～2011年流腮疫情报告资料进行分析。结果1998年起南京市鼓楼区已开始推行含流腮成份疫苗的预防接种,2008年纳入扩大的国家免疫规划。21年间流腮发病率总体呈下降趋势,每隔7～8年有一个发病高峰。预防接种改变了流腮的流行病学特征,高发年龄从未开展预防接种前的3～7岁变为扩大国家免疫规划后的10～12岁。结论预防接种是预防控制流腮的有效措施。为降低发病率,在做好常规免疫的同时,应在下一个流行高峰期到来之前,提高中、小学生的免疫覆盖率。     

Age-related changes in the rate of disease transmission: implications for the design of vaccination programmes.

Mathematical models are developed to aid in the investigation of the implications of heterogeneity in contact with infection within a community, on the design of mass vaccination programmes for the control of childhood viral and bacterial infections in developed countries. Analyses are focused on age-dependency in the rate at which individuals acquire infection, the question of ''who acquires infection from whom'', and the implications of genetic variability in susceptibility to infection. Throughout, theoretical predictions are based on parameter estimates obtained from epidemiological studies and are compared with observed temporal trends in disease incidence and age-stratified serological profiles. Analysis of case notification records and serological data suggest that the rate at which individuals acquire many common infections changes from medium to high and then to low levels in the infant, child and teenage plus adult age groups respectively. Such apparent age-dependency in attack rate acts to reduce slightly the predicted levels of herd immunity required for the eradication of infections such as measles, when compared with the predictions of models based on age-independent transmission. The action of maternally derived immunity in prohibiting vaccination in infants, and the broad span of age classes over which vaccination currently takes place in the U.K., however, argue that levels of herd immunity of between 90 and 94% would be required to eliminate measles. Problems surrounding the interpretation of apparent age-related trends in the acquisition of infection and their relevance to the design of vaccination programmes, are discussed in relation to the possible role of genetically based variation in susceptibility to infection and observations on epidemics in ''virgin'' populations. Heterogeneous mixing models provide predictions of changes in serology and disease incidence under the impact of mass vaccination which well mirror observed trends in England and Wales.     

Modelling the incidence of congenital rubella syndrome in developing countries

BACKGROUND: As of 1997, less than one-third of developing countries included rubella vaccine in their national immunization programme. In countries that have achieved high coverage of measles vaccine, an ideal opportunity exists to include control of rubella and congenital rubella syndrome (CRS) in enhanced measles control activities. Data on the burden of congenital rubella syndrome are important to guide rubella vaccination policies. METHODS: We reviewed the literature to identify studies of rubella antibody prevalence in developing countries that were conducted on populations with no major selection bias, prior to wide-scale rubella vaccination in the country. We used a simple catalytic model to describe the age-specific prevalence of susceptibility to rubella virus infection in given populations. Estimates of the incidence of infection among pregnant women were calculated using expressions for the average prevalence of susceptibility to infection and the incidence of infection during gestation. To estimate the number of cases of CRS, we assumed an overall risk of 65% after infection in the first 16 weeks of pregnancy and zero risk thereafter. These estimates were derived for each country for which data were available, then for each World Health Organization region, excluding Europe. RESULTS: The estimated mean incidence of CRS per 100,000 live births was lowest in the Eastern Mediterranean region (77.4, range 0-212) and highest in the Americas (175, range 0-598). The mean of the estimates of the total number of cases of CRS in developing countries in 1996 was approximately 110,000. The range was, however, very wide, from as few as 14,000 to as many as 308,000 cases. CONCLUSIONS: Congenital rubella syndrome is an under-recognized public health problem in many developing countries. There is an urgent need for collection of appropriate data to estimate the cost-effectiveness of a potential global rubella control programme.     

Age-related changes in the rate of disease transmission: implications for the design of vaccination programmes

Mathematical models are developed to aid in the investigation of the implications of heterogeneity in contact with infection within a community, on the design of mass vaccination programmes for the control of childhood viral and bacterial infections in developed countries. Analyses are focused on age-dependency in the rate at which individuals acquire infection, the question of 'who acquires infection from whom', and the implications of genetic variability in susceptibility to infection. Throughout, theoretical predictions are based on parameter estimates obtained from epidemiological studies and are compared with observed temporal trends in disease incidence and age-stratified serological profiles. Analysis of case notification records and serological data suggest that the rate at which individuals acquire many common infections changes from medium to high and then to low levels in the infant, child and teenage plus adult age groups respectively. Such apparent age-dependency in attack rate acts to reduce slightly the predicted levels of herd immunity required for the eradication of infections such as measles, when compared with the predictions of models based on age-independent transmission. The action of maternally derived immunity in prohibiting vaccination in infants, and the broad span of age classes over which vaccination currently takes place in the U.K., however, argue that levels of herd immunity of between 90 and 94% would be required to eliminate measles. Problems surrounding the interpretation of apparent age-related trends in the acquisition of infection and their relevance to the design of vaccination programmes, are discussed in relation to the possible role of genetically based variation in susceptibility to infection and observations on epidemics in 'virgin' populations. Heterogeneous mixing models provide predictions of changes in serology and disease incidence under the impact of mass vaccination which well mirror observed trends in England and Wales.     

Changes of the immunological patterns against measles, mumps and rubella. A vaccination programme studied 3 to 7 years after the introduction of a two-dose schedule

A two-dose vaccination programme using a combined measles, mumps and rubella vaccine (MMR) and administration at the ages of 18 months and 12 years was introduced in 1982. The 12-year-old schoolchildren were tested yearly from 1985 to 1989 on serum samples obtained prior to and after vaccination. Each year between 420 and 756 children were tested. The method used for antibody testing was the haemolysis-in-gel (HIG) assay. For measles also the enzyme-linked immunosorbent assay (ELISA) and the neutralization titre (NT) were applied. Only minor variations of the prevaccination immunity to measles were seen during the period 3-7 years after introduction of the programme. The age groups studied had partly been vaccinated against measles earlier. Between 12 and 16% lacked prevaccination immunity. In contrast the immunity to mumps and rubella of the 12-year-old children decreased considerably during the study period. No general vaccination against these diseases had been performed. Thus the susceptibility to mumps increased from 14% in 1985 to 39% in 1989 and to rubella from 41 to 57%. The seroconversion rate of children seronegative for measles was high, i.e. 100% in 1985 and later varied between 96 and 97%. For mumps, the seroconversion rate was lower and varied between 72 and 88%. All sera converted to rubella. During the follow-up period there was a declining incidence of measles, mumps and rubella. The relationship between the vaccination and reduction of disease and natural immunity strongly suggests that the association is causal and that this vaccination policy reduced the transmission of infection.     

Matrix models for childhood infections: a Bayesian approach with applications to rubella and mumps

Mathematical modelling is an established tool for planning and monitoring vaccination programmes. However, the matrices describing contact rates are based on subjective choices, which have a large impact on results. This paper reviews published models and obtains prior model probabilities based on publication frequency and expert opinion. Using serological survey data on rubella and mumps, Bayesian methods of model choice are applied to select the most plausible models. Estimates of the basic reproduction number R0 are derived, taking into account model uncertainty and individual heterogeneity in contact rates. Twenty-two models are documented, for which publication frequency and expert opinion are negatively correlated. Using the expert prior with individual heterogeneity, R0=6.1 [95% credible region (CR) 4.3-9.2] for rubella and R0=19.3 (95% CR 4.0-31.5) for mumps. The posterior modes are insensitive to the prior for rubella but not for mumps. Overall, assortative models with individual heterogeneity are recommended.