Sero-epidemiology of measles-specific IgG antibodies and predictive factors for low or missing titres in a German population-based cross-sectional study in children and adolescents (KiGGS)

The immune status of migrant populations in Europe and implications for vaccine-preventable disease control: a systematic review and meta-analysis

BACKGROUND

Ensuring vaccination coverage reaches established herd immunity thresholds (HITs) is the cornerstone of any vaccination programme. Diverse migrant populations in European countries have been associated with cases of vaccine-preventable diseases (VPDs) and outbreaks, yet it is not clear to what extent they are an under-immunized group.

METHODS

We did a systematic review and meta-analysis to synthesize peer-reviewed published primary research reporting data on the immune status of migrants in EU/EEA countries, the UK and Switzerland, calculating their pooled immunity coverage for measles, mumps, rubella and diphtheria using random-effects models. We searched on Web of Science, Embase, Global Health and MEDLINE (1 January 2000 to 10 June 2022), with no language restrictions. The protocol is registered with PROSPERO (CRD42018103666).

FINDINGS

Of 1103 abstracts screened, 62 met eligibility criteria, of which 39 were included in the meta-analysis. The meta-analysis included 75 089 migrants, predominantly from outside Europe. Pooled immunity coverage among migrant populations was well below the recommended HIT for diphtheria (n = 7, 57.4% [95% confidence interval (CI): 43.1-71.7%] I2 = 99% vs HIT 83-86%), measles (n = 21, 83.7% [95% CI: 79.2-88.2] I2 = 99% vs HIT 93-95%) and mumps (n = 8, 67.1% [95% CI: 50.6-83.6] I2 = 99% vs HIT 88-93%) and midway for rubella (n = 29, 85.6% [95% CI: 83.1-88.1%] I2 = 99% vs HIT 83-94%), with high heterogeneity across studies.

INTERPRETATION

Migrants in Europe are an under-immunized group for a range of important VPDs, with this study reinforcing the importance of engaging children, adolescents and adults in 'catch-up' vaccination initiatives on arrival for vaccines, doses and boosters they may have missed in their home countries. Co-designing strategies to strengthen catch-up vaccination across the life course in under-immunized groups is an important next step if we are to meet European and global targets for VPD elimination and control and ensure vaccine equity.

Measles Immunity Status of Greek Population after the Outbreak in 2017-2018: Results from a Seroprevalence National Survey

Accurate data on susceptibility rates against measles in the general population of Greece are scarce. Many studies have estimated the vaccination coverage, but none have calculated the nationwide immunity rate, including all age groups, against the measles virus. The purpose of our study was to determine the measles immunity status, especially after the latest outbreak in 2017-2018. In total, 3972 leftover blood samples were obtained during 2020-2021. They were collected from a nationwide laboratory network using a geographically stratified sampling strategy and were tested for the presence of measles-specific IgG antibodies. The overall crude seroprevalence was calculated to be 89.6% and the adjusted was 89.8% (95% CI: 88.8-90.8%). There was no statistically significant difference in seropositivity between sexes (p = 0.783). Higher immunity rates and antibody concentrations were found in older age groups ≥41 years old (94.9%, 95% CI: 93.7-95.9%, and 730.0 mIU/mL) in comparison with younger individuals aged 1-40 years old (83.4%, 95% CI: 81.6-85.7%, and 616.5 mIU/mL). Comparing the seroprevalence among the Nomenclature of Territorial Units for Statistics (NUTS 2), a statistically significant difference was estimated among them (<0.001). The two regions where higher measles incidence was observed during the 2017-2018 outbreak, Eastern Macedonia and Thrace, and Western Greece, were among the four regions with lower seropositivity (84.6%, 95% CI: 79.9-89.4%, and 85.9%, 95% CI: 81.4-90.4%, respectively). Our study showed a measles immunity gap that affects the younger age groups and makes a new measles outbreak likely. The enforcement of vaccination campaigns and addressing vaccine hesitancy could bridge it and achieve the required target of herd immunity.

Seroprevalence of Measles-, Mumps-, and Rubella-specific antibodies in the German adult population - cross-sectional analysis of the German Health Interview and Examination Survey for Adults (DEGS1)

BACKGROUND

The WHO European Region targets the elimination of measles, rubella, and the congenital rubella syndrome and welcomes mumps elimination via the joint MMR vaccine. In a push towards this elimination goal, Germany introduced a recommendation on MMR vaccination for adults in 2010 to prevent increasing numbers of measles cases among adults and to strengthen herd immunity.

METHODS

The prevalence of anti-measles, -mumps, and -rubella IgG antibodies was analysed in 7,115 participants between the ages of 18 and 79 years in the German Health Interview and Examination Survey. Risk factors of seronegativity of adults born 1970 or later were determined.

FINDINGS

The seroprevalence of anti-measles IgG antibodies was more than 97% in adults born before 1965 and less than 90% in adults born afterwards. Prevalence and GMTs declined with later years of birth. Seronegativity was associated with two-sided migration background and region of residence in East Germany. For anti-mumps IgG antibodies, the seroprevalence was less than 90% in almost all age groups. Prevalence and GMTs declined with later years of birth. Seronegativity was not associated with any socio-demographic factor. Anti-rubella IgG seropositivity was found in more than 90% of adults born before 1985. GMTs declined in younger age groups. Seronegativity was associated with birth between 1980 and 1993 and male gender. High socio-economic status lowered the odds of being seronegative.

INTERPRETATION

These data reinforce the implementation of the vaccination recommendation for adults and provide the basis for further evaluation of this measure.

FUNDING

The Federal Ministry of Health, Germany.

Clustering of susceptible individuals within households can drive measles outbreaks: an individual-based model exploration

When estimating important measures such as the herd immunity threshold, and the corresponding efforts required to eliminate measles, it is often assumed that susceptible individuals are uniformly distributed throughout populations. However, unvaccinated individuals may be clustered in a variety of ways, including by geographic location, by age, in schools, or in households. Here, we investigate to which extent different levels of within-household clustering of susceptible individuals may impact the risk and persistence of measles outbreaks. To this end, we apply an individual-based model, Stride, to a population of 600,000 individuals, using data from Flanders, Belgium. We construct a metric to estimate the level of within-household susceptibility clustering in the population. Furthermore, we compare realistic scenarios regarding the distribution of susceptible individuals within households in terms of their impact on epidemiological measures for outbreak risk and persistence. We find that higher levels of within-household clustering of susceptible individuals increase the risk, size and persistence of measles outbreaks. Ignoring within-household clustering thus leads to underestimations of required measles elimination and outbreak mitigation efforts.

Effect of age at vaccination on the measles vaccine effectiveness and immunogenicity: systematic review and meta-analysis

Background

The objectives of this review were to evaluate the effect of age at administration of the first dose of a measles-containing vaccine (MCV1) on protection against measles and on antibody response after one- and two-dose measles vaccinations.

Methods

We conducted a systematic review of the PubMed/MEDLINE, Embase, Web of Science and Cochrane databases (1964–2017) to identify observational studies estimating vaccine effectiveness and/or measles attack rates by age at first vaccination as well as experimental studies comparing seroconversion by age at first vaccination. Random effect models were used to pool measles risk ratios (RR), measles odds ratios (OR) and seroconversion RR of MCV1 administered at < 9, 9–11 or ≥ 15 months compared with 12 or 12–14 months of age.

Results

We included 41 and 67 studies in the measles protection and immunogenicity analyses. Older age at MCV1, from 6 to ≥15 months, improved antibody response and measles protection among one-dose recipients. Pooled measles RR ranged from 3.56 (95%CI: 1.28, 9.88) for MCV1 at < 9 months to 0.48 (95%CI: 0.36, 0.63) for MCV1 at ≥15 months, both compared to 12–14 months. Pooled seroconversion RR ranged from 0.93 (95%CI: 0.90, 0.96) for MCV1 at 9–11 months to 1.03 (95%CI: 1.00, 1.06) for MCV1 at ≥15 months, both compared to 12 months. After a second dose, serological studies reported high seropositivity regardless of age at administration of MCV1 while epidemiological data based on few studies suggested lower protection with earlier age at MCV1.

Conclusions

Earlier age at MCV1 decreases measles protection and immunogenicity after one dose and might still have an impact on vaccine failures after two doses of measles vaccine. While two-dose vaccination coverage is most critical to interrupt measles transmission, older age at first vaccination may be necessary to keep the high level of population immunity needed to maintain it.

Measles Outbreak in a Rural Population in Bahar District, Hamadan Province, West of Iran in 2018

Background: Measles is in elimination phase in Iran. Following occurrence of two cases of measles in two children under six years old with the history of measles immunization in one of the villages affiliated to Bahar District, west of Hamadan Province, northwest of Iran, this study was conducted to determine the immunity status of people living in the village affected by the measles outbreak in spring of 2018.

Study design: A cross-sectional (descriptive-analytical) study.

Methods: Overall, 272 populations of 0-40 yr old in the village affected by outbreak were enrolled. Multistage sampling was used for choosing participants. The data collection tool was a researcher-made checklist used to collect epidemiological data including demographic characteristics and vaccination status. Blood samples were taken from them and sent to the measles reference laboratory for IgG testing. The amount of optical density (OD) greater than 0.2 was considered as positive and less than 0.1 negative, respectively.

Results: The mean age of the study population was 17.4 ±11.8 yr and the sex ratio was almost the same. Levels of antibodies against measles were positive in 63.24%, intermediate in 12.5% and negative in 24.26%. There was no significant difference between the immunity status of the subjects with gender (P=0.236) and age group (P=0.113). Pearson correlation results showed that in males there was a significant positive correlation between the age of the participants and the serum IgG level (r = 0.26, P=0.003).

Conclusion: Measles immunity in communities is not sufficient to prevent outbreaks and small epidemics, and it is recommended that periodically, serological assessments carried out at community level and especially at high-risk groups.

Combining serological and contact data to derive target immunity levels for achieving and maintaining measles elimination

BACKGROUND

Vaccination has reduced the global incidence of measles to the lowest rates in history. However, local interruption of measles virus transmission requires sustained high levels of population immunity that can be challenging to achieve and maintain. The herd immunity threshold for measles is typically stipulated at 90-95%. This figure does not easily translate into age-specific immunity levels required to interrupt transmission. Previous estimates of such levels were based on speculative contact patterns based on historical data from high-income countries. The aim of this study was to determine age-specific immunity levels that would ensure elimination of measles when taking into account empirically observed contact patterns.

METHODS

We combined estimated immunity levels from serological data in 17 countries with studies of age-specific mixing patterns to derive contact-adjusted immunity levels. We then compared these to case data from the 10 years following the seroprevalence studies to establish a contact-adjusted immunity threshold for elimination. We lastly combined a range of hypothetical immunity profiles with contact data from a wide range of socioeconomic and demographic settings to determine whether they would be sufficient for elimination.

RESULTS

We found that contact-adjusted immunity levels were able to predict whether countries would experience outbreaks in the decade following the serological studies in about 70% of countries. The corresponding threshold level of contact-adjusted immunity was found to be 93%, corresponding to an average basic reproduction number of approximately 14. Testing different scenarios of immunity with this threshold level using contact studies from around the world, we found that 95% immunity would have to be achieved by the age of five and maintained across older age groups to guarantee elimination. This reflects a greater level of immunity required in 5-9-year-olds than established previously.

CONCLUSIONS

The immunity levels we found necessary for measles elimination are higher than previous guidance. The importance of achieving high immunity levels in 5-9-year-olds presents both a challenge and an opportunity. While such high levels can be difficult to achieve, school entry provides an opportunity to ensure sufficient vaccination coverage. Combined with observations of contact patterns, further national and sub-national serological studies could serve to highlight key gaps in immunity that need to be filled in order to achieve national and regional measles elimination.

Measles Status-Barriers to Vaccination and Strategies for Overcoming Them

BACKGROUND

The World Health Organization (WHO) set the year 2020 as a target date for the eradication of measles in Europe, yet Germany is still far away from this goal. In this article, we provide an overview of current vaccination gaps and barriers to vaccination among children and adults in Germany, as well as potential strategies for overcoming them.

METHODS

This review is based on pertinent publications identified by a selective literature search in PubMed (Medline).

RESULTS

Measles vaccinations are not carried out in the appropriate timely fashion in Germany. Moreover, current vaccination rates among both children and adults are too low to achieve the goal of measles eradication. For example, among children born in 2014, the recommended vaccination rate of more than 95% was only reached when these children were 24 months old. Primary care physicians bear the responsibility for this situation, as they have the greatest influence on the decision to vaccinate. The main causes of vaccination gaps are safety worries and complacen- cy on the patients' part, and partial skepticism regarding vaccination on the part of the caregivers. We identified promising strategies for overcoming these problems: an instructive talk to provide evidence-based information to patients in an atmos- phere of mutual trust, reminder systems, multifactorial interventions, and facilitated access to vaccination, or, as a last resort, the reintroduction of compulsory vacci- nation.

CONCLUSION

Primary care physicians play a key role in vaccination. The focus of further strategies should lie above all in improved patient education and in targeted reminders for patients who neglect to vaccinate themselves and/or their children.

Sero-epidemiological study in prediction of the risk groups for measles outbreaks in Vojvodina, Serbia

Background

Age-stratified serologic surveys provide insight into the gaps of measles-specific immunity as well as estimates of the age-specific seroprevalence. The aim of this study was to describe the measles sero-epidemiology in Vojvodina before the occurrence of outbreak in 2017/18 and to discuss preventive measures for potential future epidemics.

Methods

A seroprevalence study was conducted from April 2015 to June 2017 on serum bank of 3199 residual samples. Study was performed prior to the last measles outbreak in Vojvodina that occurred between 12th November 2017 and 30th June 2018. Measles-specific IgG antibodies were determined using an indirect chemiluminescent immunoassay (CLIA).

Results

Median age of enrolled participants was 20 years (IQR 11–37). Overall, 86.9% serum samples were seropositive. The highest proportion of measles seronegativity was observed in children aged 12–23 months of age and in adults aged 20–39 years (56.1% and 18.5%, respectively). Prevalence of measles seronegativity above WHO target levels susceptibility was observed in the following age groups: 2, 7, 13, 15, and among all adults aged between 20 and 49 years. Out of total measles outbreak cases (177), there were 91 (51.4%) participants aged 20–39 years. A significant positive correlation was observed between measles seronegativity and the number of reported measles cases aged ≥ 12 months (r = 0.4675, p = 0.0213).

Conclusions

In order to prevent new outbreaks and achieve the elimination of measles in Vojvodina, the vaccination coverage of both measles-mumps-rubella (MMR1 and MMR2) vaccines needs to be improved and sustained. Educational campaigns for the improvement of acceptance and timely vaccination with vaccine against measles among doctors and the general population are crucial. Our results indicate possible gap in measles protection in adults born during implementation of one dose of measles vaccine and prioritize supplementary immunization activities targeting adults in Vojvodina, Serbia.

Vaccination Coverage Disparities Between Foreign-Born and U.S.-Born Children Aged 19-35 Months, United States, 2010-2012

Healthy People 2020 targets high vaccination coverage among children. Although reductions in coverage disparities by race/ethnicity have been described, data by nativity are limited. The National Immunization Survey is a random-digit-dialed telephone survey that estimates vaccination coverage among U.S. children aged 19-35 months. We assessed coverage among 52,441 children from pooled 2010-2012 data for individual vaccines and the combined 4:3:1:3*:3:1:4 series (which includes ≥4 doses of diphtheria, tetanus, and acellular pertussis vaccine/diphtheria and tetanus toxoids vaccine/diphtheria, tetanus toxoids, and pertussis vaccine, ≥3 doses of poliovirus vaccine, ≥1 dose of measles-containing vaccine, ≥3 or ≥4 doses of Haemophilus influenzae type b vaccine (depending on product type of vaccine; denoted as 3* in the series name), ≥3 doses of hepatitis B vaccine, ≥1 dose of varicella vaccine, and ≥4 doses of pneumococcal conjugate vaccine). Coverage estimates controlling for sociodemographic factors and multivariable logistic regression modeling for 4:3:1:3*:3:1:4 series completion are presented. Significantly lower coverage among foreign-born children was detected for DTaP, hepatitis A, hepatitis B, Hib, pneumococcal conjugate, and rotavirus vaccines, and for the combined series. Series completion disparities persisted after control for demographic, access-to-care, poverty, and language effects. Substantial and potentially widening disparities in vaccination coverage exist among foreign-born children. Improved immunization strategies targeting this population and continued vaccination coverage monitoring by nativity are needed.

Public health response to a measles outbreak on a university campus in Australia, 2015

This report describes the effective public health response to a measles outbreak involving a university campus in Brisbane, Australia. Eleven cases in total were notified, mostly university students. The public health response included targeted measles vaccination clinics which were established on campus and focused on student groups most likely to have been exposed. The size of the university population, social interaction between students on and off campus, as well as limited vaccination records for the university community presented challenges for the control of this extremely infectious illness. We recommend domestic students ensure vaccinations are current prior to matriculation. Immunisation information should be included in university student enrolment packs. Incoming international students should ensure routine vaccinations are up-to-date prior to arrival in Australia, thereby reducing the risk of importation of measles and other infectious diseases.

Seroprevalence of Measles Antibodies and Predictors for Seropositivity among Chinese Children

Background: Supplementary measles immunization has been implemented since 2010 throughout China, yet few studies have reported its effect in the northwest regions. Methods: A cross-sectional study was conducted among children aged 2 to 4 years old (n = 755) from February to September 2014 in 25 towns of Qian County, Shaanxi Province. Blood samples were analyzed for measles antibodies using enzyme-linked immunosorbent immunoglobulin G (IgG) assays. Socio-demographic factors were assessed by questionnaire. Data on vaccine dose were collected from town medical records. Univariate and logistic regression analyses were used to determine factors associated with measles antibody seropositivity. Results: Measles antibody seroprevalence was 91.13% (95% CI: 89.52-92.83) in our sample. Compared with children whose mother's highest education was primary school, seroprevalence was higher in children whose maternal education was middle school (adjusted OR: 1.4, 95% CI: 0.7-2.8), high school (adjusted OR: 2.4, 95% CI: 1.3-7.7), and college/university (adjusted OR: 2.9, 95% CI: 1.2-9.3). Vaccine dose was positively associated with seropositivity. Conclusions: Measles seroprevalence is high in China and is associated with the mother's education and vaccine dose.

Association between seroprevalence of measles and various social determinants in the year following a measles outbreak in Turkey

OBJECTIVES

Despite an ongoing measles elimination programme, a measles outbreak occurred in 2013 in Turkey. Population-based seroprevalence studies are needed to determine seronegativity and explore the reasons for this outbreak. This study aimed to explore the seroprevalence of measles and its association with various social determinants in a provincial population in Turkey in the year following a measles outbreak.

STUDY DESIGN

Cross-sectional study.

METHODS

This study was conducted in Manisa Province in 2014 in a sample of 1740 people aged >2 years. The dependent variable was the seroprevalence of measles. Independent variables were sex, age, migration, household size, household density, income, education level, existence of chronic disease and occupational class. Blood samples were collected from participants at family health centres. The presence of specific measles antibodies in serum samples was determined using an anti-measles virus IgG enzyme-linked immunosorbent assay test. Chi-squared test and logistic regression analysis were performed.

RESULTS

Overall, data from 1250 people were analysed. The seroprevalence of measles in the whole study population was 82.2% (95% confidence interval 80.0-84.2). Seroprevalence was 55.4% among subjects aged 2-9 years, 48.7% among subjects aged 10-19 years, 74.1% among subjects aged 20-29 years and 93.6% among subjects aged 30-39 years (P < 0.01). Seroprevalence in subjects aged >40 years was >95%. The lowest seroprevalence was found in primary school children (40.2%), followed by those below the age for primary education (69.8%) and secondary school graduates (75.1%). The prevalence of measles seronegativity was not associated with any of the social determinants when adjusted for age.

CONCLUSIONS

The seroprevalence of measles was lower than expected in the study population and was particularly low in subjects aged <30 years of age despite previous vaccination. Seroprevalence was not associated with social determinants of health that confirmed either an even distribution of virus exposure or fair access to vaccination services. However, the current seroprevalence cannot be sufficiently effective to reach the measles elimination targets, suggesting that it may be necessary to re-evaluate the need for an extra dose of measles vaccine.

Serological assessment of the establishment of herd immunity against measles in a health district in Malaysia

Background

Malaysia still faces challenges optimizing resources to effectively eliminate measles through high immunization and herd immunity, with sporadic outbreaks of measles as evidence. The objective of this study is to determine the age-specific positive measles antibodies seroprevalence used for assessing the establishment of herd immunity against measles in different age groups. This is useful for identifying vulnerable age groups requiring supplementary immunization.

Methods

A seroprevalence study was conducted among respondents aged 6–9 years, 15–24 years and 45–54 years attending government health clinics in Seremban between September 2014 and January 2015. A total of 1541 measles IgG antibody status were determined using ELISA technique (NovaTec Immundiagnostica GMBH) and assessment of establishment of herd immunity was based on indicators developed by Plans. Data on socio-demographic background as well as medical and medication history were also gathered.

Results

Seropositive rate for all respondents were 87% (95% CI 85–89), while the rest had either indeterminate [6% (95% CI 5–7)] or negative titre [7% (95% CI 6–8)]. None of the factors analyzed except for age were significant predictors of positive measles antibodies. Seropositive rate differed by age with the highest rate seen in adults (94%; CI 92–96), followed by children (90%; 95% CI 87–94) and adolescents, and young adults (74%; 95% CI 70–78). Based on Plans’ indicators, herd immunity was established in adults and children, but not in adolescents and young adults.

Conclusions

To tackle the most susceptible group in the present study, it is advisable to give booster vaccination to secondary school students and freshmen who enter colleges and universities in Malaysia.

Synthesis of Evidence to Characterize National Measles and Rubella Exposure and Immunization Histories

Population immunity depends on the dynamic levels of immunization coverage that countries achieve over time and any transmission of viruses that occur within the population that induce immunity. In the context of developing a dynamic transmission model for measles and rubella to support analyses of future immunization policy options, we assessed the model inputs required to reproduce past behavior and to provide some confidence about model performance at the national level. We reviewed the data available from the World Health Organization (WHO) and existing measles and rubella literature for evidence of historical reported routine and supplemental immunization activities and reported cases and outbreaks. We constructed model input profiles for 180 WHO member states and three other areas to support disease transmission model development and calibration. The profiles demonstrate the significant variability in immunization strategies used historically by regions and member states and the epidemiological implications of these historical choices. The profiles provide a historical perspective on measles and rubella immunization globally at the national level, and they may help immunization program managers identify existing immunity and/or knowledge gaps.

Systematic Review of Measles and Rubella Serology Studies

Serological tests provide information about individual immunity from historical infection or immunization. Cross-sectional serological studies provide data about the age- and sex-specific immunity levels for individuals in the studied population, and these data can provide a point of comparison for the results of transmission models. In the context of developing an integrated model for measles and rubella transmission, we reviewed the existing measles and rubella literature to identify the results of national serological studies that provided cross-sectional estimates of population immunity at the time of data collection. We systematically searched PubMed, the Science Citation Index, and references we identified from relevant articles published in English. We extracted serological data for comparison to transmission model outputs. For rubella, serological studies of women of child-bearing age provide information about the potential risks of infants born with congenital rubella syndrome. Serological studies also document the loss of maternal antibodies, which occurs at different rates for the different viruses and according to the nature of the induced immunity (i.e., infection or vaccine). The serological evidence remains limited for some areas, with studies from developed countries representing a disproportionate part of the evidence. The collection and review of serological evidence can help program managers identify immunity gaps in the population, which may help them better understand the characteristics of individuals within their populations who may participate in transmission and manage risks.

Measles among migrants in the European Union and the European Economic Area

Aims: Progress towards meeting the goal of measles elimination in the EU and the European Economic Area (EEA) by 2015 is being obstructed, as some children are either not immunized on time or never immunized. One group thought to be at increased risk of measles is migrants; however, the extent to which this is the case is poorly understood, due to a lack of data. This paper addresses this evidence gap by providing an overview of the burden of measles in migrant populations in the EU/EEA. Methods: Data were collected through a comprehensive literature review, a country survey of EU/EEA member states and information from measles experts gathered at an infectious disease workshop. Results: Our results showed incomplete data on measles in migrant populations, as national surveillance systems do not systematically record migration-specific information; however, evidence from the literature review and country survey suggested that some measles outbreaks in the EU/EEA were due to sub-optimal vaccination coverage in migrant populations. Conclusions: We conclude that it is essential that routine surveillance of measles cases and measles, mumps and rubella (MMR) vaccination coverage become strengthened, to capture migrant-specific data. These data can help to inform the provision of preventive services, which may need to reach out to vulnerable migrant populations that currently face barriers in accessing routine immunization and health services.

Seroprevalence of measles and rubella virus antibodies in the population of the Community of Madrid, 2008-2009

The seroprevalence (SP) of measles and rubella virus antibodies is presented by age groups obtained in the IV Serosurvey of the Region of Madrid (2008-2009). The target population is composed of residents with ages ranging between 2 and 60 years in the Region of Madrid. A two-stage cluster sample is used. The SP of measles virus antibodies is 97.8% (CI 95%: 97.3-98.2). The highest SP is observed in the 2-5 year and 41-60 year age groups. The point estimate does not reach 95% in the 16-20 and 21-30 year age groups. The SP of rubella virus antibodies is 97.2% (CI 95%: 96.5-97.7). The SP is over 95% in all of the age groups. In immigrant women between the ages of 16 and 49, the SP is 95.9% (CI 95%: 93.7-97.4). The identification of groups susceptible to the measles virus in young adults could lead to outbreaks as a result of importing the virus. The circulation of the rubella virus is possible among immigrant women aged between 16 and 49 years, which could lead to the appearance of SRC cases. Epidemiological surveillance will allow the impact on the measles and rubella elimination plan to be determined in the future.

National and international initiatives and approaches for the establishment of reference intervals in pediatric laboratory medicine

Thoroughly validated laboratory medicine reference intervals for children of all ages groups have been published increasingly during the last years. The aim of this review is to present a number of these studies and the various approaches to the generation of reference intervals. Population-based data obtained in large cohorts of healthy children in Germany, Northern Europe, North America, and selected other countries as well as patient-derived data collected in many areas of the world are discussed. Additionally, special research aspects such as reference intervals for preterm neonates, preanalytical issues, intraindividual variation of analytes, or follow-up studies that are covered in many of these studies are presented.

[Vaccination coverage against measles and sero-epidemiology of measles-specific IgG antibodies in German children and adolescents]

BACKGROUND

Measles is a vaccine-preventable disease that could be eliminated by global vaccination strategies with two-dose measles vaccination. The World Health Organization (WHO) European Region aims at achieving measles elimination by 2015. Target control is mainly based on verification of 95 % vaccination coverage. In Germany, target verification cannot be based on data from centrally collected registers on vaccination and seroprevalence of measles-specific antibodies.

OBJECTIVE

This paper provides an overview of measles vaccination coverage and the timeliness of measles vaccination in birth cohorts 1989-2008. In addition, factors associated with vaccination gaps are described.

METHODS

Primary data on vaccination coverage (annual school entrance health examination) and on vaccination coverage and immune status (population-based German Health Interview and Examination Survey for Children and Adolescents - KiGGS) and secondary data (insurance refund claim data) are described and discussed.

RESULTS AND CONCLUSION

The measles immunization coverage (two doses) obtained in the 2010 school entrance examinations was 91.5 %. The range was 87.6-95.3 % between Federal States. Regional differences were even more pronounced between districts. The timeliness of the two-dose measles immunization increased from 41 % (birth cohorts 2001/2002) to 66 % (birth cohorts 2006/2008). Despite progress in recent years, measles vaccination coverage is still inadequate in adolescents, young adults, and young children. The German Standing Committee on Vaccination (STIKO) recommends a combined MMR vaccination of adults who were born after 1970 and who were not fully vaccinated against measles during childhood. Successful implementation of this recommendation is crucial just as it is important to step up efforts to improve the timeliness of measles vaccination in young children. Regional vaccination gaps and susceptible clusters defined by age or sociodemographic parameters are of particular importance to the epidemiology of measles disease. Knowledge of the factors associated with nonimmunization should be used to tailor vaccination strategies.

Measles outbreak spreading from the community to an anthroposophic school, Berlin, 2011

Between April and July 2011 there was an outbreak of measles virus, genotype D4, in Berlin, Germany. We identified 73 case-patients from the community and among students of an anthroposophic school, who participated in a 4-day school trip, as well as their family and friends. Overall, 27% were aged ≥ 20 years, 57% were female and 15% were hospitalized. Of 39 community case-patients, 38% were aged ≥ 20 years, 67% were female and 63% required hospitalization. Unvaccinated students returning from the school trip were excluded from school, limiting transmission. Within the group of 55 school-trip participants, including 20 measles case-patients, a measles vaccine effectiveness of 97.1% (95% confidence interval 83.4-100) for two doses was estimated using exact Poisson regression. Our findings support school exclusions and the recommendation of one-dose catch-up vaccination for everyone born after 1970 with incomplete or unknown vaccination status, in addition to the two-dose routine childhood immunization recommendation.

[Vaccination coverage in German adults: results of the German Health Interview and Examination Survey for Adults (DEGS1)]

In the absence of an immunisation register, vaccination coverage in Germany must be estimated. Ten years after the German National Health Interview and Examination Survey 1998 (GNHIES98), the population survey DEGS1 is one of the data sources to be used for monitoring vaccination coverage. In the survey, data on vaccination history were obtained from vaccination cards and self-reports. The prevalence of immunisation for tetanus and diphtheria was higher compared to the prevalence estimated ten years previously in GNHIES98. Nonetheless, 28.6 % of adults have not been vaccinated against tetanus and 42.9 % have not been vaccinated against diphtheria within the last ten years. Vaccination is especially low among the elderly, among adults with low socio-economic status and in western Germany. During the last ten years, only 11.8 % of women and 9.4 % of men were vaccinated against pertussis in western Germany; vaccination coverage was twice as high in eastern Germany. In 2009, recommendations were published to combine the next tetanus immunisation with a pertussis immunisation; therefore pertussis vaccination coverage might improve in the coming years. The lifetime prevalence of influenza vaccination obtained in DEGS1 is higher than the annual vaccination rate for influenza. However, the lifetime prevalence among adults aged 60 years or older is still below the annual rate of 75 % recommended by the WHO. An English full-text version of this article is available at SpringerLink as supplemental.

Vaccination coverage among children in Germany estimated by analysis of health insurance claims data

In Germany, the national routine childhood immunization schedule comprises 12 vaccinations. Primary immunizations should be completed by 24 mo of age. However, nationwide monitoring of vaccination coverage (VC) is performed only at school entry. We utilized health insurance claims data covering ~85% of the total population with the objectives to (1) assess VC of all recommended childhood vaccinations in birth-cohorts 2004-2009, (2) analyze cross-sectional (at 24 and 36 mo) and longitudinal trends, and (3) validate the method internally and externally. Counting vaccine doses in a retrospective cohort fashion, we assembled individual vaccination histories and summarized VC to nationwide figures. For most long-established vaccinations, VC at 24 mo was at moderate levels (~73-80%) and increased slightly across birth-cohorts. One dose measles VC was high (94%), but low (69%) for the second dose. VC with a full course of recently introduced varicella, pneumococcal, and meningococcal C vaccines increased across birth-cohorts from below 10% above 60%, 70%, and 80%, respectively. At 36 mo, VC had increased further by up to 15 percentage points depending on vaccination. Longitudinal analysis suggested a continued VC increase until school entry. Validation of VC figures with primary data showed an overall good agreement. In conclusion, analysis of health insurance claims data allows for the estimation of VC among children in Germany considering completeness and timeliness of vaccination series. This approach provides valid nationwide VC figures for all currently recommended pediatric vaccinations and fills the information gap between early infancy and late assessment at school entry.

Measles in children vaccinated with 2 doses of MMR

OBJECTIVE

A previous measles outbreak investigation in a high school in Quebec, Canada identified 2-dose vaccine effectiveness of 94%. The risk of measles in 2-dose recipients was significantly higher (2-4 times) when measles vaccine was first administered at 12 versus ≥ 15 months of age, with no significant effect of the age at second dose. Generalizability of this association was also assessed in the expanded provincial data set of notified cases.

METHODS

This matched case-control study included only 2-dose recipients. All confirmed (laboratory or epidemiologically linked) cases in patients aged 5 to 17 years were included. Each case was matched to 5 controls.

RESULTS

A total of 102 cases and 510 controls were included; 89% of cases were in patients 13 to 17 years old. When the first dose was administered at 12 to 13 months compared with ≥ 15 months of age, the risk of measles in participants outside the outbreak school was 6 times higher (95% confidence interval, 1.33-29.3) and was 5.2 times higher (95% confidence interval, 1.91-14.3) in the pooled estimate (participants from the outbreak school + outside that school).

CONCLUSIONS

A significantly greater risk of measles among 2-dose recipients whose first dose was given at 12 to 13 months rather than ≥ 15 months of age is confirmed in the larger Quebec data set. The mechanism remains unknown, but vaccine failures in 2-dose recipients could have substantial implications for measles elimination efforts through 2-dose vaccination. The optimal age at first dose may warrant additional evaluation.

High risk of a large measles outbreak despite 30 years of measles vaccination in The Netherlands

Our aim was to assess progress towards measles elimination from The Netherlands by studying humoral measles immunity in the Dutch population. A population-based seroepidemiological study was conducted in 2006-2007 (N = 7900). Serum samples were analysed by a bead-based multiplex immunoassay. IgG levels ⩾0·2 IU/ml were considered protective. The overall seroprevalence in the Dutch population was 96%. However, 51% of socio-geographically clustered orthodox Protestant individuals aged <10 years were susceptible. Infants might be susceptible to measles between ages 4 months and 14 months, the age at which maternal antibodies have disappeared and the first measles, mumps, rubella (MMR) vaccination is administered, respectively. Waning of antibody concentrations was slower after the second MMR vaccination than after the first. The Netherlands is at an imminent risk of a measles outbreak in the orthodox Protestant minority. To prevent subsequent transmission to the general population, efforts to protect susceptible age groups are needed.

Seroprevalence of measles-, mumps- and rubella-specific IgG antibodies in German children and adolescents and predictors for seronegativity

We have undertaken a seroprevalence study with more than 13,000 children, who had been included in the German KIGGS survey, a representative sample of children and adolescents 0-17 years of age. The IgG titres against measles, mumps and rubella were determined in 1 to 17 year olds While 88.8% of the children were MMR-vaccinated at least once, 76.8% of children aged 1 to 17 years showed prevalence of antibodies to MMR. The highest seronegativity was seen with respect to mumps. Gender differences were most pronounced with regard to rubella IgG titres: girls aged 14 to 17 years were best protected, although seronegativity in 6.8% of this vulnerable group still shows the need of improvement. Search for predictors of missing seroprevalence identified young age to be the most important predictor. Children living in the former West and children born outside of Germany had a higher risk of lacking protection against measles and rubella, while children with a migration background but born in Germany were less often seronegative to measles antibodies than their German contemporaries. An association of seronegativity and early vaccination was seen for measles but not for mumps and rubella. A high maternal educational level was associated with seronegativity to measles and rubella. In vaccinated children, seronegativity was highest for mumps and lowest for rubella. For mumps, high differences were observed for seronegativity after one-dose and two-dose vaccination, respectively. Seronegativity increases as time since last vaccination passes thus indicating significant waning effects for all three components of MMR.