The seroepidemiology of rubella in western Europe

Identifying the population susceptible to rubella in Japan, 2020: Fine-scale risk mapping

BACKGROUND

Rubella remains a public health challenge in Japan, impeding the attainment of herd immunity. Despite vaccination efforts since 1976, persistent outbreaks reveal a susceptibility gap in male adults born before 1995. Seroepidemiological surveys are pivotal in evaluating population immunity and identifying at-risk groups.

METHODS

This study aims to pinpoint high-risk areas for potential rubella outbreaks in Japan by merging seroepidemiological data from 2020 with population census information. Various data sources, including spatial demographic data, reported rubella and congenital rubella syndrome (CRS) cases, and traveler lodging statistics, were employed. Geospatial information for Japan's 230,300 small geographic areas was analyzed, and HI (hemagglutination inhibition) titers were examined by age and sex. Seroconversion was defined as an HI titer ≥ 1:32 or 1:16, indicating protective immunity. Geospatial maps illustrated the distribution of susceptible individuals per square kilometer, emphasizing high-risk urban areas like Tokyo and Osaka. Demographic shifts in the working-age population were assessed.

RESULTS

Susceptible individuals cluster in densely populated urban centers, persisting despite demographic changes. The study highlights areas at risk of increased susceptibility, particularly with an HI titer cut-off of 1:16. Foreign travelers pose potential rubella importation risks as travel volume to Japan rises. To prevent epidemics and congenital rubella syndrome burden, achieving and sustaining herd immunity in high-risk areas is crucial.

CONCLUSIONS

This study offers a comprehensive assessment of vulnerability in densely populated Japanese regions. Integrating population statistics with seroepidemiological data enhances our understanding of population immunity, guiding resource allocation for supplementary vaccination planning. To avert rubella epidemics, high-risk locations must bolster indirect protection through herd immunity, ultimately preventing congenital rubella syndrome.

Parity status and the relationship between antenatal rubella serology with obstetric outcome

Routine antenatal rubella serological testing is adopted in many countries. In a population covered by universal childhood rubella immunization for four decades, we have observed an association between pre-eclampsia with maternal rubella seronegativity among multiparous gravidae. This retrospective cohort study was further performed to elucidate the interaction between parity status and rubella seronegativity on obstetric outcome in singleton pregnancies carried to ≥ 24 weeks gestation managed from 1997 to 2019, with the data retrieved from a computerized database used for annual statistics and auditing. Of the 133,926 singleton pregnancies eligible for the study, the 13,320 (9.9%) rubella seronegative gravidae had higher mean booking weight and body mass index (BMI), but shorter height, and higher incidence of advanced age (≥ 35 years), high BMI, short stature, and lower incidence of nulliparas. Univariate analysis showed that adverse obstetric outcomes were more frequently found among the multiparas. On multivariate analysis, there was increased postdated (> 41 weeks) pregnancy irrespective of parity status, while nulliparas had reduced gestational hypertension (aRR 0.714, 95% CI 0.567-0.899) and gestational diabetes (aRR 0.850, 95% CI 0.762-0.950), and multiparas had increased pre-eclampsia (aRR 1.261, 95% CI 1.005-1.582), neonatal death (aRR 2.796, 95% CI 1.243-6.291), and perinatal death (aRR 2.123, 95% CI 1.257-3.587). In conclusion, in a population covered by universal childhood rubella immunization, antenatal rubella seronegativity is associated with increased pre-eclampsia and perinatal loss only in multiparas, suggesting that the rubella seronegativity in these women served as proxy for some form of altered immune response which increases adverse pregnancy outcome.

Rubella Seroprevalence Boost in the Pediatric and Adolescent Population of Florence (Italy) as a Preventive Strategy for Congenital Rubella Syndrome (CRS)

BACKGROUND

Despite the availability of an effective vaccine since the 1970s, rubella disease and, importantly, congenital rubella syndrome (CRS) remain a public health concern. The aim of this study was to analyze the rubella seroprevalence in the children population of the province of Florence and compare the obtained results to a previous survey conducted in 2005-2006.

METHODS

A qualitative measurement of anti-rubella antibodies was performed on 165 sera using the enzyme-linked immunosorbent Assay (ELISA). The anamnestic and vaccination status was also collected.

RESULTS

Our study highlighted a very high rubella seroprevalence (85-100%) in our enrolled population. In the vaccinated group (153/165), 98.7% of them were positive to rubella antibodies.

CONCLUSIONS

Our study showed the highest seroprevalence rate reached in the province of Florence for rubella in the last 15 years, thanks to the several successful vaccination campaigns promoted in the Tuscany region. Our findings in pediatric and adolescent subjects are a key factor in preventing CRS in adult life, specifically in childbearing women. Thus, the set goal will be to keep the awareness about the vaccination for this preventable disease high.

Identifying geographic areas at risk of rubella epidemics in Japan using seroepidemiological data

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Seroepidemiological data enabled us to compute the effective reproduction number.

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Risks of a major epidemic were high in areas with capital cities.

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Urban geographic areas possess small epidemic risk due to low volume of travelers.

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Urban areas have a large number of susceptible adult males aged 30–59 years.

Objective

Even with relatively high vaccination coverage, Japan experienced rubella epidemics in 2012–2014 and 2018–2019, which were fueled by untraced imported cases. We aimed to develop a risk map for rubella epidemics in Japan by geographic location via analysis of seroepidemiological data and accounting for the abundance of foreign visitors.

Methods

Geographic age distribution and seroprevalence were used to compute the age- and sex-dependent next-generation matrix in each region. We computed the probability of a major epidemic using the assumed number of untraced imported rubella cases proportionally modeled to the number of foreign travelers.

Results

Risks of a major epidemic were high in areas with capital cities, while areas with a greater fraction of older people yielded smaller effective reproduction numbers, a lower volume of foreign travelers, and thus a lower probability of a major epidemic. The volume of susceptible adult males was larger in urban geographic regions, having a greater number of foreign travelers than remote areas.

Conclusions

Our findings are consistent with the observation of multiple large clusters of rubella cases in urban areas during 2012–2014 and 2018–2019. Should a future rubella epidemic occur, it will likely be in geographic areas with capital cities.

Comparative studies of rubella virus immunity of immunized and non-immunized pregnant women visiting Kogi State University Teaching Hospital, Anyigba, North Central Nigeria

Rubella is endemic worldwide and poses a serious threat to infants and pregnant women. Although the disease has been widely reported in parts of the country, there is currently no documented evidence of the disease in Anyigba. A comparative study of rubella immunity was conducted among immunized and non-immunized pregnant women visiting the Kogi State University Teaching Hospital, Anyigba. In a cross-sectional study, blood samples collected from 300 pregnant women (immunized = 127; non-immunized = 173) were tested for rubella antibodies using ELISA kit. Overall, anti-rubella-IgM and IgG seroprevalence rates of 38 (12.7%) and 83 (27.7%) were detected. Seventy (55.1%) of the immunized against 13 (7.5%) of non-immunized women had detectable IgG. The non-immunized women were significantly more seropositive for IgM than the immunized who recorded higher prevalence of IgG. Immunized and non-immunized women aged 23-32 years had higher IgG and IgM positivity rates. The difference in IgM and IgG seropositivity rates in relation to vaccination was statistically significant (P < 0.05) between the immunized (0.8%, 55.1%) and vaccine-naïve subjects (21.4%, 7.5%). Low level of awareness and high susceptibility to rubella virus infection especially among the non-immunized women was confirmed in study area, thus the need for government to strengthen education of masses and to make rubella vaccination freely available for women of childbearing age.

Hepatitis B Seroprevalence in the Pediatric and Adolescent Population of Florence (Italy): An Update 27 Years after the Implementation of Universal Vaccination

BACKGROUND

Hepatitis B still represents a health concern, although safe and effectivevaccines have been available since 1982. Italy introduced a program of universal vaccination againsthepatitis B in 1991. The aim of this study was to assess the immunity levels towards hepatitis B in asample of sera from the pediatric and adolescent population in the province of Florence, CentralItaly, twenty-seven years after the implementation of universal vaccination.

METHODS

A total of 165sera samples were collected from the resident population of Florence aged 1-18 years. The anti-HBsand anti-HBc enzyme-linked immunosorbent Assay (ELISA) tests were performed on all samples.The anamnestic and vaccination status data were also collected.

RESULTS

Seroprevalence of anti-HBswas approximately 60%, with children aged 1-5 years having the highest positivity rate (81.6%),and decreasing trends in the older age groups. The zero prevalence of anti-HBc shows that thedetected protective immunity is mainly due to vaccination, and natural infection was not reportedin the studied population.

CONCLUSIONS

The seroprevalence of anti-HBs and the lack of anti-HBc inthis study highlights that immunity levels have been derived mainly from immunization. Thisconfirms how vaccination dramatically reduced circulation of the hepatitis B virus in Italy in thepediatric and adolescent population twenty-seven years after implementation of the mandatoryuniversal program.

Resurgence risk for measles, mumps and rubella in France in 2018 and 2020

Large measles and mumps outbreaks recently occurred throughout Europe and the United States. Aim: Our aim was to estimate and map the risk of resurgence for measles, mumps and rubella in France. Methods: We used a multi-cohort model combining seroprevalence information, vaccine coverage and social contact data. Results: The overall outbreak risk for France in 2018 was highest for mumps, remained significant for measles despite a recent measles outbreak and was low for rubella. Outbreak risks were heterogeneous between departments, as the effective reproduction numbers for 2018 ranged from 1.08 to 3.66. The seroprevalence, and therefore the risk of measles and rubella infection, differed significantly between males and females. There was a lower seroprevalence, and therefore a higher risk, for males. Infants of less than 1 year would be seriously affected in a future outbreak of measles, mumps or rubella, but the highest overall caseload contribution would come from teenagers and young adults (10–25 years old). Conclusions: The high risk for teenagers and young adults is of concern in view of their vulnerability to more severe measles, mumps and rubella disease and complications.

Cytomegalovirus Anterior Uveitis: Clinical Characteristics and Long-term Outcomes in a French Series

PURPOSE

To report the characteristics of cytomegalovirus anterior uveitis (CMV AU) and the comparative response to 2 types of antiviral induction treatments.

DESIGN

Retrospective, consecutive case series.

METHODS

Consecutive immunocompetent patients with polymerase chain reaction-positive CMV AU were included. For each patient, best-corrected visual acuity (BCVA), intraocular pressure (IOP), clinical characteristics at baseline and latest visit, and number of relapses were recorded. All patients received an induction dose of intravenous (IV) ganciclovir or oral valganciclovir and a maintenance dose of oral valganciclovir.

RESULTS

Thirty-six eyes of 35 patients were included. Mean age at diagnosis was 55.5 years. Mean follow-up was 4.13 years. Posner-Schlossman and chronic nonspecific AU were observed in 69.4% and 30.6% of cases, respectively. We did not observe any case of Fuchs uveitis or endotheliitis. At baseline, mean BCVA was 20/25 and mean IOP was 29.19 mm Hg. Keratic precipitates and iris atrophy were seen in 91.4% and 25.7% of cases. Induction therapy consisted of oral valganciclovir and IV ganciclovir in 40% and 60% of cases. A total of 94.2% of patients responded to the first line of therapy. Recurrence was reported in 73.5% of cases. Glaucoma surgery was necessary in 25.7% of cases. Early initiation of antiviral therapy (≤700 days) seemed to decrease the recourse to glaucoma surgery. Both IV and oral induction treatments seemed similar in terms of BCVA changes and occurrence of relapses.

CONCLUSIONS

Characteristics of CMV AU seem to show specificities in this French cohort. Early initiation of antiviral therapy seems to reduce the severity of glaucoma.

Global seroprevalence of rubella among pregnant and childbearing age women: a meta-analysis

Background

We conducted a meta-analysis of articles published between January 2000 and July 2016 with the aim of defining the proportion of rubella seronegative women of childbearing age (WCBA), providing the best information available on the seroprevalence of rubella in this population. We selected articles published in the time period between 2000 and 2016. The pooled prevalence of rubella seronegative women was calculated by a fixed effect model and a random effect model, according to the heterogeneity among studies. Studies were sub-grouped by population type (pregnant women and WCBA with no mention of ongoing pregnancy) and by geographic area [World Health Organization (WHO) region]. Sensitivity analysis was performed to assess the stability of results. We found important differences in rubella seronegativity prevalence estimates by WHO Region. About 88% of the studies conducted on pregnant women reported a seronegativity rate >5%. The pooled rubella seronegativity prevalence was 9.3%. When considering population groups, we obtained a seronegativity pooled estimate of 9.4% for pregnant women and of 9.5% for WCBA with no mention of ongoing pregnancy. This meta-analysis shows that the proportion of WCBA who are susceptible to rubella is still high. The figures are worrisome, taking into account that the WHO set at 5% the rubella susceptibility threshold for WCBA.

A systematic review of varicella seroprevalence in European countries before universal childhood immunization: deriving incidence from seroprevalence data

Surveillance systems for varicella in Europe are highly heterogeneous or completely absent. We estimated the varicella incidence based on seroprevalence data, as these data are largely available and not biased by under-reporting or underascertainment. We conducted a systematic literature search for varicella serological data in Europe prior to introduction of universal varicella immunization. Age-specific serological data were pooled by country and serological profiles estimated using the catalytic model with piecewise constant force of infection. From the estimated profiles, we derived the annual incidence of varicella infection (/100·000) for six age groups (<5, 5–9, 10–14, 15–19, 20–39 and 40–65 years). In total, 43 studies from 16 countries were identified. By the age of 15 years, over 90% of the population has been infected by varicella in all countries except for Greece (86·6%) and Italy (85·3%). Substantial variability across countries exists in the age-specific annual incidence of varicella primary infection among the <5 years old (from 7052 to 16 122 per 100 000) and 5–9 years old (from 3292 to 11 798 per 100 000). The apparent validity and robustness of our estimates highlight the importance of serological data for the characterization of varicella epidemiology, even in the absence of sampling or assay standardization.

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.

Seroepidemiology: an underused tool for designing and monitoring vaccination programmes in low- and middle-income countries

Seroepidemiology, the use of data on the prevalence of bio-markers of infection or vaccination, is a potentially powerful tool to understand the epidemiology of infection before vaccination and to monitor the effectiveness of vaccination programmes. Global and national burden of disease estimates for hepatitis B and rubella are based almost exclusively on serological data. Seroepidemiology has helped in the design of measles, poliomyelitis and rubella elimination programmes, by informing estimates of the required population immunity thresholds for elimination. It contributes to monitoring of these programmes by identifying population immunity gaps and evaluating the effectiveness of vaccination campaigns. Seroepidemiological data have also helped to identify contributing factors to resurgences of diphtheria, Haemophilus Influenzae type B and pertussis. When there is no confounding by antibodies induced by natural infection (as is the case for tetanus and hepatitis B vaccines), seroprevalence data provide a composite picture of vaccination coverage and effectiveness, although they cannot reliably indicate the number of doses of vaccine received. Despite these potential uses, technological, time and cost constraints have limited the widespread application of this tool in low-income countries. The use of venous blood samples makes it difficult to obtain high participation rates in surveys, but the performance of assays based on less invasive samples such as dried blood spots or oral fluid has varied greatly. Waning antibody levels after vaccination may mean that seroprevalence underestimates immunity. This, together with variation in assay sensitivity and specificity and the common need to take account of antibody induced by natural infection, means that relatively sophisticated statistical analysis of data is required. Nonetheless, advances in assays on minimally invasive samples may enhance the feasibility of including serology in large survey programmes in low-income countries. In this paper, we review the potential uses of seroepidemiology to improve vaccination policymaking and programme monitoring and discuss what is needed to broaden the use of this tool in low- and middle-income countries.

Serological makers of rubella infection in Africa in the pre vaccination era: a systematic review

BACKGROUND

Rubella infections in susceptible women during early pregnancy often results in congenital rubella syndrome (CRS). World Health Organisation (WHO) recommends that countries without vaccination programmes to assess the burden of rubella infection and CRS. However; in many African countries there is limited data on epidemiology of rubella infection and CRS. This review was undertaken to assess the serological markers and genotypes of rubella virus on the African continent in order to ascertain the gap for future research.

FINDINGS

A systematic search of original literatures from different electronic databases using search terms such as 'rubella' plus individual African countries such as 'Tanzania', 'Kenya', 'Nigeria' etc. and different populations such as 'children', 'pregnant women' etc. in different combinations was performed. Articles from countries with rubella vaccination programmes, outbreak data and case reports were excluded. Data were entered in a Microsoft Excel sheet and analyzed. A total of 44 articles from 17 African countries published between 2002 and 2014 were retrieved; of which 36 were eligible and included in this review. Of all population tested, the natural immunity of rubella was found to range from 52.9 to 97.9 %. In these countries, the prevalence of susceptible pregnant women ranged from 2.1 to 47.1 %. Rubella natural immunity was significantly higher among pregnant women than in general population (P < 0.001). Acute rubella infection was observed to be as low as 0.3 % among pregnant women to 45.1 % among children. All studies did not ascertain the age-specific prevalence, thus it was difficult to calculate the rate of infection with increase in age. Only two articles were found to report on rubella genotypes. Of 15 strains genotyped; three rubella virus genotypes were found to circulate in four African countries.

CONCLUSION

Despite variations in serological assays, the seroprevalence of IgG rubella antibodies in Africa is high with a substantial number of women of childbearing age being susceptible to rubella infection. Standardized sero-epidemiological data in various age groups as well as CRS data are important to implement cost-effective vaccination campaigns and control strategies.

Estimating seroprevalence of vaccine-preventable infections: is it worth standardizing the serological outcomes to adjust for different assays and laboratories?

The aim of the European Sero-Epidemiology Network 2 (ESEN2) project was to estimate age-specific seroprevalence for a number of vaccine-preventable diseases in Europe. To achieve this serosurveys were collected by 22 national laboratories. To adjust for a variety of laboratory methods and assays, all quantitative results were transformed to a reference laboratory's units and were then classified as positive or negative to obtain age-specific seroprevalence. The aim of this study was to assess the value of standardization by comparing the crude and standardized seroprevalence estimates. Seroprevalence was estimated for measles, mumps, rubella, diphtheria, varicella zoster and hepatitis A virus (HAV) and compared before and after serological results had been standardized. The results showed that if no such adjustment had taken place, seroprevalence would have differed by an average of 3·2% (95% bootstrap interval 2·9-3·6) although this percentage varied substantially by antigen. These differences were as high as 16% for some serosurveys (HAV) which means that standardization could have a considerable impact on seroprevalence estimates and should be considered when comparing serosurveys performed in different laboratories using different assay methods.

A cohort study of a tailored web intervention for preconception care

Background

Preconception care may be an efficacious tool to reduce risk factors for adverse pregnancy outcomes that are associated with lifestyles and health status before pregnancy. We conducted a web-based cohort study in Italian women planning a pregnancy to assess whether a tailored web intervention may change knowledge and behaviours associated with risks for adverse pregnancy outcomes.

Methods

The study was entirely conducted on the web on a cohort of Italian women of childbearing age. Data collected at baseline on health status, lifestyles and knowledge of risk factors for adverse pregnancy outcomes were used for generating a tailored document including recommendations for folic acid supplementation, obesity and underweight, smoking, alcohol consumption, vaccinations, chronic and genetic diseases, exposure to medications. Prevalence of risk factors and knowledge was assessed 6 months after the intervention. Logistic regression models were used to explore the factors associated with risk factors after the intervention.

Results

Of the 508 enrolled women, 282 (55.5%) completed the study after 6 months since the delivery of tailored recommendations. At baseline, 48% of the participants took folic acid supplementation (95% CI 43.2; 51.9) and 69% consumed alcohol (95% CI 64.7; 72.9). At the follow up 71% of the participants had a preconception visit with a physician. Moreover we observed a decrease of alcohol consumption (−46.5% 95% CI −53.28; −38.75) and of the proportion of women not taking folic acid supplementation (−23.4% 95% CI −31.0; 15.36). We observed an improvement in knowledge of the information about the preconception behaviours to prevent adverse pregnancy outcomes (20.9% 95% CI 14.6%; 27.1%). Having a preconception visit during follow up was significally associated to an increase in folic acid supplementation (OR 2.53 95% CI 1.40; 4.60).

Conclusions

Our results suggest that a tailored web intervention may improve general preconception health in women planning a pregnancy. A web preconception intervention may be integrated with classic preconception care by health professionals. Clinical trials should be conducted to confirm these findings.

Passive immunization for the public health control of communicable diseases: current status in four high-income countries and where to next

The practice of passive immunization with human immune globulin (IG) for the control of communicable diseases (measles, rubella and hepatitis A) differs somewhat between Australia, the United States of America, the United Kingdom, and New Zealand despite the many similarities of these countries, including disease incidence rates and population immunity. No minimum effective dose of IG has been identified for protecting susceptible contacts of measles or hepatitis A. Recommended passive immunization practice for susceptible pregnant contacts of rubella is based on limited evidence in all countries. We suggest that gaps in the evidence base need to be addressed to appropriately inform the role of passive immunization in public health practice into the future.

Rubella antibody screening during pregnancy in an urban area of Northern Italy

Various countries have implemented anti-rubella vaccination campaigns with the main aim of preventing congenital infection. In 2003, Italy joined the European WHO programme for the elimination of congenital rubella and issued a special healthcare plan, one of the objectives of which was to reduce the proportion of rubella-susceptible pregnant women to less than 5% by 2005. The aim of this study was to determine the percentage of seronegative pregnant women after the implementation of this plan. Anti-rubella IgG and IgM antibodies were sought in 2385 pregnant women who attended our hospital for serological screening between 1 July 2008 and 30 June 2010. They included 750 women of foreign origin (31.4%). Eight percent of the women were anti-rubella seronegative: 6.2% of the Italians and 11.7% of the non-Italians. Among the women of foreign origin, the percentage of seronegativity ranged from 5.6% of those coming from Eastern Europe to 17.7% of those coming from Latin America. The level of seropositivity among women of Italian origin is high, although the objective of ensuring less than 5% of susceptible pregnant women has not yet been quite reached in our area. However, particular attention needs to be given to women coming from geographical areas characterised by different epidemiologies and vaccination strategies because the percentage of seronegativity is in some cases double that of Italian women.

Chronic hepatitis B virus infection and rubella susceptibility in pregnant women

Increased rubella susceptibility has been shown in subjects from the Asian-Pacific region where chronic hepatitis B virus (HBV) infection is endemic. This study was performed to explore the relationship between chronic HBV infection and rubella susceptibility in the obstetric population. We conducted a retrospective cohort study on 50556 pregnant women delivered in a university obstetric unit from January 1998 to June 2008. The incidence of rubella susceptibility according to maternal HBV carrier status was examined. HBV infection and rubella susceptibility were found in 5105 (10.1%) and 6102 (12.1%) women, respectively. Rubella susceptibility was more common in women with HBV (13.1%vs 12.0%, P = 0.017), even after adjusting for other confounding factors (odds ratio 1.11, 95% confidence interval 1.01-1.21). Advancing age was associated with progressively decreasing odds of rubella susceptibility, from 0.48 at age 20-24 years to 0.34 at age ≥ 40 years in women without HBV infection, but had no effect in women with hepatitis B. In conclusion, our study is the first to demonstrate an association between chronic HBV infection with rubella susceptibility. Further studies are warranted to confirm whether chronic HBV infection, especially that acquired by vertical transmission, may impair the immune response to rubella vaccine or natural infection throughout the reproductive age.

European Sero-Epidemiology Network 2: standardisation of immunoassay results for pertussis requires homogeneity in the antigenic preparations

A standardisation process, already developed during the earlier European Sero-Epidemiology Network (ESEN) project, was employed with a more robust algorithm to harmonise results of pertussis serological assays performed in 12 European and non-European countries. Initially, results from each country's own assay were compared with those obtained at the reference laboratory by means of an in-house pertussis toxin (PT)-based ELISA: seven countries used in-house or commercial PT-ELISAs; the other countries used assays based on Bordetella pertussis whole cell extracts (WCE) (three countries) or on combined PT-FHA (filamentous haemagglutinin) antigenic preparations (two countries). The WCE assays, although admitted for diagnostic purposes, confirmed their low correlation with the PT-ELISAs and their results could not be used for standardisation; the PT-FHA ELISAs gave results that were suitable for standardisation in one country but unsatisfactory in the other; the use of purified PT in serological assays confirmed its better reliability than other preparations and all PT-ELISAs results could be calibrated against those of the reference centre. In the standardisation process two high-titre cut-offs indicative of likelihood of recent infection (from within 4 weeks of disease onset up to 1 year after) were included for evaluations as they are suggested to be more useful, for the sero-epidemiological assays of immunity to pertussis, than the cut-off of protection, commonly employed, but still not defined for pertussis. Providing PT-ELISAs are used, standardisation of pertussis assay results is always possible and, when standardisation is performed, evaluation and comparison of the impact of different interventions can be also allowed, by measuring at the distribution of high antibody titres in the populations.

Comparison of rubella seroepidemiology in 17 countries: progress towards international disease control targets

OBJECTIVE

To standardize serological surveillance to compare rubella susceptibility in Australia and 16 European countries, and measure progress towards international disease-control targets.

METHODS

Between 1996 and 2004, representative serum banks were established in 17 countries by collecting residual sera or community sampling. Serum banks were tested in each country and assay results were standardized. With a questionnaire, we collected information on current and past rubella vaccination programmes in each country. The percentage of seronegative (< 4 IU/ml) children (2-14 years of age) was used to evaluate rubella susceptibility, and countries were classified by seronegativity as group I (< 5%), group II (5-10%) or group III (> 10%). The proportion of women of childbearing age without rubella protection (< or = 10 IU/ml) was calculated and compared with WHO targets of < 5%.

FINDINGS

Only Romania had no rubella immunization programme at the time of the survey; the remaining countries had a two-dose childhood schedule using the measles, mumps and rubella (MMR) vaccine. The percentage of susceptible children defined five countries as group I, seven as group II and four as group III. Women of childbearing age without rubella protection were < 5% in only five countries.

CONCLUSION

Despite the low reported incidence in many countries, strengthening the coverage of the routine two-dose of MMR vaccine among children is needed, especially in group III countries. Catch-up campaigns in older age groups and selective targeting of older females are needed in many countries to ensure necessary levels of protective immunity among women of childbearing age.

Seroepidemiology of hepatitis B in Greek children 6 years after the implementation of universal vaccination

The seroepidemiology of hepatitis B in children living in Greece 6 years post-implementation of universal infant immunization (1998) was studied. We collected 90-100 sera/year of age, stratified by geographic region. The prevalence of HbsAg(+) was 0.6% (95% CI 0.3-1.3) whereas 4.5% (95% CI 3.4-5.9%) of children over 12 months of age had evidence of past HBV infection. A significant decline in the prevalence of past infection between children born before and after 1998 (5.5% vs 2.9%; RR = 1.9, 95% CI 1.03-3.5) was noted. Conversely, the prevalence of past HBV infection did not change significantly among immigrant children. Reinforcement of early vaccination of immigrant population is necessary.

Topical calcineurin inhibitors in pediatric atopic dermatitis: a critical analysis of current issues

Atopic dermatitis (AD) is a common disease in children. Despite good skin care and trigger avoidance, many children with AD require pharmacologic treatment to manage their disease. In recent years, topical calcineurin inhibitors (TCIs) have been used as an alternative to topical corticosteroids to treat some children with AD. However, revisions to the US labeling for TCIs (i.e. a boxed warning and a medication guide) have generated concern among pediatricians regarding TCI safety and raised questions about the appropriate use of TCIs in the pediatric population. Data from several well designed studies support the efficacy of TCIs in the treatment of AD. Safety concerns arise from a small number of reported malignancies, animal toxicology studies, and the potential adverse effects (including immunosuppression and risk of lymphoma) observed in patients who received systemically administered calcineurin inhibitors for suppression of solid-organ transplant rejection. Several factors indicate that these effects do not occur with topical administration: (i) systemic levels following topical administration are at least 10-fold lower than with oral administration; (ii) the small number of lymphomas reported to date in persons exposed to TCI use are not consistent with the types seen in transplant patients or other immunosuppressed patients; and (iii) no adverse effects on the immune system (as assessed by measures including vaccination response and skin delayed-type hypersensitivity reaction) have been observed in clinical trials of TCIs in children with AD. Overall, TCIs have an established safety and efficacy profile as long-term maintenance therapy in children with AD.

Rubella immune status of indigenous and immigrant pregnant women in Catalonia, Spain

BACKGROUND

The objective of the study was to determine the prevalence of rubella antibodies in representative samples of pregnant women in Catalonia.

METHODS

A representative sample of pregnant women in Catalonia was obtained by random sampling by clusters (hospitals with maternity units) stratified by provinces. Blood was obtained from the umbilical cord at childbirth in 1538 women (of whom 308 were immigrants) and was tested for rubella antibodies by ELISA (Enzime-linked immunosorbent assay).

RESULTS

The global prevalence of antibodies was 93.4% [95% confidence interval (CI): 93.3-93.5] and was significantly higher in indigenous women (94.9;95%CI:93.3-95.9) compared with immigrants [89.0; 95%CI: 85.5-92.5 (P<0. 0001)] with crude Odds ratio (OR) of 2.15 (95%CI: 1.40-3.32).The prevalence was higher in women living in rural habitats (97%) and those in higher social classes (96.3%); OR 2.54 (95%CI: 1.22-5.30) and 2.17 (95%CI: 1.24-3.81), respectively.

CONCLUSION

Fertile female immigrants from countries with no vaccination or where vaccination coverage is low should be actively approached for vaccination to reduce the risk of infection and congenital rubella.

Seroprevalence of rubella among Jordanian women of childbearing age

This study was conducted to assess immunity (seroprevalence) to rubella among Jordanian women of childbearing age. A multistage cluster sampling was used to recruit 1125 women of childbearing age (15-49 year) from the 12 Governorates of Jordan. Anti-rubella antibody titers were measured using enzyme-linked immunoassays. The overall immunity rate to rubella among women in childbearing age was 90.9% (CI: 88.8-92.9). However, the immunity rate was significantly lower in younger women aged 15-19 years (83%) compared to the whole cohort (P</=0.001) which means potential increased risk for congenital rubella syndrome (CRS). Immunity rates did not differ between regions and between urban and rural areas. Since the main priority is to decrease CRS among relatively susceptible cohorts, we recommend modifying the existing Expanded Program on Immunization with inclusion of a second dose of rubella vaccine at school entry (6 years of age) to decrease circulation of the virus among susceptible young females. We also recommend yearly catch-up school vaccination of young females entering the 10th grade for the next 10 years. Strengthening of rubella and CRS surveillance programs is also recommended in parallel with pre-marriage counseling regarding rubella and CRS for young females.

Seroprevalence of rubella infection after national immunization program in Taiwan: vaccination status and immigration impact

Rubella vaccination was implemented nationwide in 1992 in Taiwan. A cross-sectional survey was conducted to determine the age-specific seroprevalence of anti-rubella in female students aged 7-22 years old and women of reproductive age in Taipei County. Seropositivity of anti-rubella antibodies was defined as a serum IgG level > or =10 IU/ml tested by enzyme immunoassay. Information on possible predictors of anti-rubella seronegativity was obtained from structured questionnaire interview. Multivariate-adjusted odds ratios (ORm) with their 95% confidence interval (CI) were derived for each predictor using multiple logistic regression analysis. A total of 826 female students and 318 women were recruited. Anti-rubella seropositive rates were 98.3% (282/287), 99.6% (234/235), 96.8% (179/185), 92.4% (110/119), 81.4% (197/242), and 89.5% (68/76) for the age groups of 7-9, 11-13, 15-17, 19-22, 25-33, and 34-44 years old, respectively. Among female students, negative serology for rubella antibodies was associated significantly with the age group and foreign nationality of mother, showing ORm (95% CI) of 1.2 (1.06-1.27) for each year increase in age, and 20.9 (6.31-68.97), respectively. Among women at the reproductive age, low maternal education level 91.6 (9.12-920.74), unmarried status 21.2 (6.16-72.89), and no rubella vaccination 98.9 (11.64-840.25) were associated significantly with an increased evidence of seronegativity to rubella. The National Rubella Vaccination Program has led to herd immunity of school girls. However, in order to eradicate the Rubella syndrome, greater effort is required to vaccinate foreign brides in Taiwan.

Rubella seroprofile of the Italian population: an 8-year comparison

The objective of this study is to evaluate how increasing MMR infant vaccination coverage in recent years has modified the epidemiology of rubella in Italy. A cross-sectional population-based seroprevalence study of rubella antibodies was conducted on 3094 sera, in 2004, and results were compared with data obtained by the same method in 1996. The overall proportion of rubella-seropositive individuals was found to be significantly higher in 2004 with respect to 1996 (84.6% vs. 77.4%). However, an increase in seropositivity was observed only in the 1-19 years age groups. Recent increases in childhood MMR vaccination coverage, therefore, have not had an impact on seroprevalence in women of childbearing age, over 5% of whom remain susceptible to rubella. Preconception screening and postpartum vaccination of susceptible women are fundamental if the WHO target of less than one case of congenital rubella syndrome per 100,000 live births is to be attained.

Seroprevalence of measles, rubella, and mumps antibodies in Catalonia, Spain: results of a cross-sectional study

Determination of antibody levels against vaccine-preventable diseases is of great value to assess immunization programmes. The objective of this study was to determine the prevalence of measles, rubella, and mumps antibodies in representative samples of the child and adult population of Catalonia and compare the findings to those obtained in 1996. A representative sample of the child and adult (>or=15 years) population of Catalonia was studied. Enzyme-linked immunosorbent assay techniques were used to determine the presence of antibodies. Equivocal results for antibodies against measles and rubella were tested using an immunofluorescence technique. To compare proportions, the chi-square test and the Fisher's exact test were used. Statistical significance was set at 0.05. Adjusted odds ratios were calculated using multiple logistic regression analysis. Samples from 2,619 people were analyzed. The global prevalence of antibodies was 98.3% for measles, 91.1% for mumps, and 98.1% for rubella. The prevalence of rubella antibodies was higher in women than in men (98.8 vs. 97.2%, respectively). Compared with the results obtained in the 1996 seroprevalence study, only the prevalence of rubella antibodies showed a statistically significant increase in men (97.2 vs. 94.6%; p=0.002) and, in particular, in women (98.8 vs. 95.3%; p<0.001). The low prevalence of susceptible subjects has already led to the elimination of indigenous measles in Catalonia and should allow the elimination of indigenous rubella by 2005. The level of antibodies necessary to interrupt the transmission of mumps has still not been reached in all age groups.

Use of rubella seroepidemiological data for assessment of previous vaccination policy and for decision making in response to epidemics in Israel

We examined the prevalence of rubella antibodies in a representative sample of the Israeli population. Three thousand three hundred and twenty-six sera collected during 1997 and 1998, from an age-stratified general population sample were tested for specific IgG antibodies against rubella. The sero-positivity rates to rubella were higher among females as compared with males (89.1% versus 82.3%, respectively (p < 0.001). This difference was the result of much lower sero-positivity rates among males in the age group 13-17, with the lowest value (56.3%) among subjects aged 16. Male subjects of this age group were in 2000 the target of an outbreak of rubella among 18-19-year old male recruits of the Israel Defense Force. The data of this study served to assess previous exposure to the wild virus or vaccine strains, to identify pockets of low level of immunity and contributed to decision making in response to the onset of a rubella outbreak.

Safety and tolerability of 1% pimecrolimus cream among infants: experience with 1133 patients treated for up to 2 years

Pimecrolimus is a calcineurin inhibitor developed for the topical treatment of atopic dermatitis. During the clinical development of 1% pimecrolimus cream, 1133 patients 3 to 23 months of age with mild to severe atopic dermatitis were treated for up to 2 years. The objective of this review is to discuss the safety and tolerability of 1% pimecrolimus cream among infants, on the basis of the combined results from all studies (4 pharmacokinetic studies and 6 clinical trials) conducted among these patients. Pimecrolimus blood concentrations measured for 35 patients were consistently low (< or =1 ng/mL in >80% of samples), irrespective of the disease severity and extent, and remained low during intermittent treatment for up to 1 year. The level of systemic exposure to pimecrolimus among infants was comparable to that observed for older pediatric patients enrolled in the same studies and treated in the same way with 1% pimecrolimus cream, which indicated that young pediatric patients are not at higher risk of significant percutaneous absorption of topically applied pimecrolimus, despite their large skin surface area/body mass ratio. The 6 clinical trials included a total of 1098 infants, who were treated for periods ranging from 4 weeks to 2 years. Most of these patients (60%) had moderate to severe disease at baseline. The most frequently reported adverse events were common childhood disorders such as nasopharyngitis, pyrexia, upper respiratory tract infections, ear infections, and bronchitis. During the double-blind (DB) studies or DB phases of studies, the incidence rates for the most frequently reported adverse events were similar for patients who received 1% pimecrolimus cream and patients who received the vehicle, except for the incidence of teething, which was higher among the pimecrolimus-treated infants (relative risk: 2.02; 95% confidence interval: 1.32-3.27). Treatment with 1% pimecrolimus cream was not associated with an increase in the overall incidence of nonskin infections, compared with the vehicle (relative risk: 1.015; 95% confidence interval: 0.88-1.18). The incidence density (ID) rates for total bacterial, fungal, parasitic, and viral skin infections during the DB studies or DB phases of studies were comparable for patients treated with 1% pimecrolimus cream and patients who received the vehicle. The ID rate of herpes simplex virus infections was 0.8 cases per 1000 patient-months of follow-up monitoring among patients treated with 1% pimecrolimus cream and 1.7 cases per 1000 patient-months of follow-up monitoring among patients who received the vehicle. Considering all 1098 infants treated with 1% pimecrolimus cream in DB trials and open-label studies, the ID rate of clinically diagnosed eczema herpeticum was 1.3 cases per 1000 patient-months of follow-up monitoring. Burning and erythema were the most frequently reported application site reactions, with ID rates of 2.0 and 1.2 cases per 1000 patient-months of follow-up monitoring, respectively. No sign of immunosuppression was found among infants treated intermittently with 1% pimecrolimus cream for up to 2 years; they demonstrated normal immune responses to vaccinations and did not show increases in the incidence of systemic infections or skin infections over time.

Model selection methodology for inter-laboratory standardisation of antibody titres

The aim of the European Sero-Epidemiology Network 2 (ESEN2) is to compare standardised serological results of vaccine preventable diseases across Europe. In order to adjust for laboratory and assay differences, the participant laboratories tested a standardisation panel for each disease and the results were plotted against those of a reference centre in order to obtain standardisation equations. We describe an algorithm for obtaining these equations which took into account outliers, censored data and model selection, and needed to be robust due to the variety of assays and diseases under investigation. If the standardisation equations explained sufficient variability, these were used to convert each country's main serum bank results to a common unitage, thereby allowing international comparisons to be made.

Long-term treatment of atopic dermatitis with pimecrolimus cream 1% in infants does not interfere with the development of protective antibodies after vaccination

OBJECTIVE

We investigated whether treatment of atopic dermatitis with pimecrolimus cream 1% in infants affects the development of a normal antibody response to vaccinations.

METHODS

In all, 91 patients participated in a 1-year, open-label extension to a 1-year double-blind study: 76 used pimecrolimus twice daily at the first signs or symptoms of the disease until clearance for 2 years and 15 only in the second year. Serum concentrations of antibodies against tetanus, diphtheria, measles, and rubella were measured at months 18 and 24.

RESULTS

The seropositivity rates of 93.6% for tetanus, 88.6% for diphtheria, 88.5% for measles, and 84.4% for rubella were comparable with those reported in literature. Seropositivity was not significantly affected by the use of pimecrolimus at the time of vaccinations (+/- 28 days).

CONCLUSIONS

Treatment of atopic dermatitis with pimecrolimus cream 1% in early childhood does not appear to interfere with the development of a normal immune response to vaccinations.

Declining seroprevalence of rubella antibodies among young Israeli adults: a 12-year comparison

BACKGROUND

In March 2000, the Israel Defense Force (IDF) experienced an outbreak of rubella. No population-based rubella seroepidemiologic data were available for the 13-year period preceding the epidemic.

METHODS

We conducted a population-based seroprevalence study of rubella antibodies among 289 IDF recruits drafted in 1999.

RESULTS

We found that 69.2% of males and 90.8% of females in service were seropositive at recruitment in 1999, immediately before the outbreak. These rates were significantly lower than those last measured in 1987 (88% among males and 98.1% among females).

CONCLUSIONS

Our findings indicate that this rubella outbreak among young adults was facilitated by a decrease in immunity to levels below those required for herd immunity, at which epidemic virus transmission was no longer blocked. This is most likely due to widespread pediatric vaccination coverage with incomplete catch-up immunization among adolescents and young adults. These findings serve as a reminder that changes to childhood vaccination programs may affect the epidemiology of disease among older segments of the population several years after the change is implemented.

Congenital rubella infection following rubella outbreak in northern Italy, 2002: need for an effective vaccination programme

Presented here are the details of a rubella outbreak that occurred in 2002 in the Lombardy region of northern Italy followed by a discussion of rubella vaccination policy in this country. From 13 maternal cases of rubella infection, congenital rubella infection was diagnosed in three fetuses and three newborns. Of the three infected fetuses, one was aborted and two died in utero, while of the three infected newborns, two were born with severe disease and one was subclinically infected. Follow-up revealed that one of the two symptomatic newborns had died at 4 months of age with disseminated rubella infection, while the other suffered from bilateral blindness and deafness and was severely retarded at 15 months of age. The remaining infant remained asymptomatic at 14 months. Congenital rubella remains a serious health problem in Italy and a successful vaccination strategy is required.

Development of a rubella vaccination strategy: contribution of a rubella susceptibility study of women of childbearing age in Kyrgyzstan, 2001

To contribute to the development of a rubella vaccination strategy, we conducted a study to determine age-specific susceptibility among women aged 15-39 years by testing for rubella-specific IgG antibodies. Of 964 women, 13% were found to be susceptible to rubella. Significantly higher susceptibility among women >25 years old was observed. Susceptibility data are important but are not sufficient to develop a vaccination strategy. After considering all available information, we suggested vaccination of women aged <35 years and selective vaccination of older women who were planning pregnancy.

Étude de l’infection par le virus de la rubéole chez l’enfant et l’adolescent en Tunisie

Rubella is a worlwide common infection; its importance in public health relates to the risk of malformation when primary infection occurs during pregnancy. This serosurvey was conducted to assess the kinetics of rubella infection in Tunisian children and teenagers and to determine the proportion of girls who remain seronegative at childbearing age. The studied population included 2481 individuals aged seven (N =1136), 13 (N =711) and 19 years (N =634), this sample was collected in 1996 and is representative of all geographical regions of the country. Our results indicate that 42% of tunisians are infected before seven years, 73% before 13 and 89% before 19 years of age. These rates are lower than those previously reported in the country. The proportion of seronegatives at 19 years of age was higher in costal regions than in the rest of the country: 14 vs 5% (p =0,0008). This difference should be due to the higher socio-economic level of the population living in costal regions. Our study indicates that primary infection with rubella virus in Tunisia is progressively shifting to older ages, which may increase the risk of congenital rubella syndrome. The introduction of rubella vaccination in the national program of vaccination may be considered, however only very high coverage levels will have a positive effect. Beside the reduction of the risk of congenital rubella syndrome, rubella vaccination will reduce the incidence of febrile rush cases and thus facilitate the surveillance activities conducted as part of the national program of measles elimination.

Time-resolved fluorometric immunoassay for rubella antibody--a useful method for serosurveillance studies

Rubella antibody (IgG) has been measured in females reporting for antenatal screening using single radial haemolysis (SRH) and time-resolved fluorescence immunoassay (TRFIA). We have shown TRFIA to be a simple, specific, highly sensitive, quantitative assay for rubella IgG with a lower limit of detection of 0.2IU/ml. Out of 506 sera tested by SRH, 18 (3.6%) had low levels of antibody (< 15IU/ml) compared to 83 (16.4%) tested by TRFIA and, of these, 32 (6.3%) had rubella antibody concentrations < 10IU/ml. The lowest level (3.1%) of rubella susceptibility (antibody levels < 10IU/ml) was found in females aged 25-29 and the highest level of susceptibility (23.5%) occurred in females aged 40 years, and over. Geometric mean rubella antibody concentrations (IU/ml) were 26.8, 34.4, 34.8, 29.7, 27.5 and 20.0 for age groups <20, 20-24, 25-29, 30-34, 35-39 and > or =40 years, respectively. Our rubella vaccination policies have built up good levels of rubella immunity in women of childbearing age in our locality, and using TRFIA technology we can accurately monitor changes over time.