Vaccination coverage in indigenous and immigrant children under 3 years of age in Catalonia (Spain)

Measles, mumps, and rubella vaccination coverage: an ecological study of primary health care and socio-economic factors in Catalonia, Spain

This study examined the association of socio-economic factors and the structure of primary care centres (PCCs) with measles, mumps, and rubella (MMR) vaccination coverage among the 8-year-old population in Catalonia, Spain. We conducted an ecological study to retrospectively assess the MMR vaccination-recorded status of children born in 2012, using public health data extracted in December 2020. For each of 300 PCCs serving 70,498 children, we calculated vaccination coverage rates from electronic health records and linked these rates to a composite deprivation index corresponding to the territory served by each PCC. We identified a relationship between unfavourable socio-economic factors and higher recorded vaccination coverage. On average, directly managed PCCs had higher vaccination coverage rates than indirectly managed PCCs. Greater utilisation of primary care services by the population was also associated with higher vaccination coverage rates. Further research is needed to generate knowledge valuable for informing more equitable child-vaccination service delivery models.

Defining the determinants of vaccine uptake and undervaccination in migrant populations in Europe to improve routine and COVID-19 vaccine uptake: a systematic review

Understanding why some migrants in Europe are at risk of underimmunisation and show lower vaccination uptake for routine and COVID-19 vaccines is critical if we are to address vaccination inequities and meet the goals of WHO's new Immunisation Agenda 2030. We did a systematic review (PROSPERO: CRD42020219214) exploring barriers and facilitators of vaccine uptake (categorised using the 5As taxonomy: access, awareness, affordability, acceptance, activation) and sociodemographic determinants of undervaccination among migrants in the EU and European Economic Area, the UK, and Switzerland. We searched MEDLINE, CINAHL, and PsycINFO from 2000 to 2021 for primary research, with no restrictions on language. 5259 data sources were screened, with 67 studies included from 16 countries, representing 366 529 migrants. We identified multiple access barriers-including language, literacy, and communication barriers, practical and legal barriers to accessing and delivering vaccination services, and service barriers such as lack of specific guidelines and knowledge of health-care professionals-for key vaccines including measles-mumps-rubella, diphtheria-pertussis-tetanus, human papillomavirus, influenza, polio, and COVID-19 vaccines. Acceptance barriers were mostly reported in eastern European and Muslim migrants for human papillomavirus, measles, and influenza vaccines. We identified 23 significant determinants of undervaccination in migrants (p<0·05), including African origin, recent migration, and being a refugee or asylum seeker. We did not identify a strong overall association with gender or age. Tailored vaccination messaging, community outreach, and behavioural nudges facilitated uptake. Migrants' barriers to accessing health care are already well documented, and this Review confirms their role in limiting vaccine uptake. These findings hold immediate relevance to strengthening vaccination programmes in high-income countries, including for COVID-19, and suggest that tailored, culturally sensitive, and evidence-informed strategies, unambiguous public health messaging, and health system strengthening are needed to address access and acceptance barriers to vaccination in migrants and create opportunities and pathways for offering catch-up vaccinations to migrants.

Receipt of routine preventive care among infant daughters and sons of immigrant mothers in Ontario, Canada: a retrospective cohort study

OBJECTIVES

To explore gender disparities in infant routine preventive care across maternal countries of birth (MCOB) and by mother tongue among infants of Indian-born mothers.

SETTING

Retrospective population-based administrative cohort in Ontario, Canada (births between 2002 and 2014).

PARTICIPANTS

350 366 (inclusive) healthy term singletons belonging to families with a minimum of one opposite gender child.

OUTCOME MEASURES

Fixed effects conditional logistic regression generated adjusted ORs (aORs) for a daughter being underimmunised and having an inadequate number of well-child visits compared with her brother, stratified by MCOB. Moderation by maternal mother tongue was assessed among children to Indian-born mothers.

RESULTS

Underimmunisation and inadequate well-child visits were common among both boys and girls, ranging from 26.5% to 58.2% (underimmunisation) and 10.5% to 47.8% (inadequate well-child visits). depending on the maternal birthplace. Girls whose mothers were born in India had 1.19 times (95% CI 1.07 to 1.33) the adjusted odds of inadequate well-child visits versus their brothers. This association was only observed among the Punjabi mother tongue subgroup (aOR: 1.26, 95% CI 1.08 to 1.47). In the Hindi mother tongue subgroup, girls had lower odds of underimmunisation than their brothers (aOR: 0.73, 95% CI 0.54 to 0.98).

CONCLUSIONS

Gender equity in routine preventive healthcare is mostly achieved among children of immigrants. However, daughters of Indian-born mothers whose mother tongue is Punjabi, appear to be at a disadvantage for well-child visits compared with their brothers. This suggests son preference may persist beyond the family planning stage among some Indian immigrants.

Comparison of early childhood vaccination coverage and timeliness between children born to Italian women and those born to foreign women residing in Italy: A multi-centre retrospective cohort study

BACKGROUND

Compared to hosting populations, immigrants are usually considered more vulnerable to communicable diseases, many of which are vaccine-preventable. This study aims to estimate vaccination coverage (VC) and timeliness in children born to women from high migratory pressure countries (HMPC) and to evaluate factors affecting differences with children born to Italian women or women from advanced development countries (ITA + ADC).

METHODS

We retrospectively analysed data of children born in 2009-2014 and resident in areas served by three local health units in the cities of Rome (n = 40,284), Turin (n = 49,600), and Treviso (n = 20,080). Data were retrieved through record-linkage of the population, vaccination, and birth registries. We used the Kaplan-Meier method to estimate VCs at different ages for the 3rd dose of vaccine against tetanus and the 1st dose of vaccines against measles and meningococcal group C. Factors affecting differences in VCs by citizenship were evaluated using log-binomial models.

RESULTS

In Rome, VCs at 2 years of age were consistently higher in children born to ITA + ADC women than in children born to HMPC women, while differences in VCs by citizenship varied according to antigen and birth-cohort in Turin and Treviso, respectively. Where differences were observed, these were only partially explained by the mother's socio-demographic characteristics, level of utilisation of health-services during pregnancy, and maternal, perinatal, and neonatal outcomes. Finally, we observed a reduction of VCs in recent birth cohorts (2012-14 vs. 2009-11), especially in children born to ITA + ADC women.

CONCLUSIONS

Differences in VCs by citizenship were not homogeneous and varied according to geographical context, antigen, and birth-cohort. These differences are likely to be also affected by informal barriers (e.g., linguistic and cultural barriers), which should be addressed in implementing strategies to increase vaccine uptake in foreign children. Moreover, our results suggest that effective strategies to promote vaccinations in the autochthonous population are also needed.

Social inequities in vaccination coverage among infants and pre-school children in Europe and Australia - a systematic review

BACKGROUND

Herd immunity levels of vaccine uptake are still not reached in some high-income countries, usually in countries with persisting social inequities in uptake. Previous studies have focused on factors within one health care system. This study takes a broader health care systems approach by reviewing the socioeconomic distribution of vaccination coverage on the national level in light of structural and organizational differences of primary care for children.

METHODS

A systematic literature review of socio-economic patterns of uptake of Measles-Mumps-Rubella (MMR) and/or Diphteria-Tetanus-Pertusis (DTP) in population based studies of children 0-5 years of age living in the 30 European Economic Area (EEA) or European Free Trade Association (EFTA) countries and Australia, was carried out using the PRISMA guidelines. The health care system in the countries in the study were categorized by degree of freedom of the primary care provider (hierarchical or non-hierarchical) and whether preventive services were provided in a separate organization (well-baby clinics).

RESULTS

The review identified 15 studies from 10 European countries and Australia that fulfilled the criteria. Although the heterogeneity of the socio-economic indicators did not allow for a conclusive meta-analysis, the study pointed towards lower levels of inequities in primary care models with well-baby clinics. In non-hierarchical primary care organizations that also lacked well-baby clinics, socioeconomic gaps in uptake were often found to be large.

CONCLUSION

This review indicates that structural and organizational aspects of health care systems for young children are important for equity in vaccine uptake.

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.

Comparison of rubella immunization rates in immigrant and Italian women of childbearing age: Results from the Italian behavioral surveillance system PASSI (2011-2015)

Background

International migration rapidly increased in the last decade, raising a renewed attention to its impact on public health. We evaluated differences in rubella immunization rate (RIR) between immigrant and Italian women of childbearing age and tried to identify the driving factors causing them.

Methods

We analyzed data from the Italian behavioral surveillance system PASSI collected in 2011–2015 in a nationally representative sample of residents in Italy. The analysis was performed using log-binomial models to compare RIR between 41,094 Italian women and 3140 regular immigrant women of childbearing age (18–49 years), stratifying the latter by area of origin and length-of-stay in Italy (recent: ≤ 5-years; mid-term: 6-10-years; long-term: > 10-years).

Results

Immigrant women showed a RIR of 36.0% compared to 60.2% among Italian women (RIR-ratio = 0.60, 95% confidence interval (CI): 0.57–0.63). Adjusting for demographic characteristics (i.e., sex, age and area of residence), socio-economic factors (i.e., education, occupation, family composition and economic status) and an indicator of the presence of at least one health-risk behavior (i.e., physical inactivity, current cigarette smoking, excessive alcohol consumption and excess weight) did not significantly change this difference (RIR-ratio = 0.56, 95% CI: 0.53–0.59). Recent immigrants (RIR-ratio = 0.47, 95% CI: 0.42–0.53) and immigrants from high migratory pressure countries (HMPC) in sub-Saharan Africa (RIR-ratio = 0.41, 95% CI: 0.31–0.56) and Asia (RIR-ratio = 0.42, 95% CI: 0.33–0.53) showed the greatest differences in RIR compared with Italian women.

Conclusions

Differences in RIR between immigrant and Italian women were not explained by different demographic, socioeconomic and health-risk behaviors characteristics. As entitlement to free-of-charge immunization in Italy is universal, regardless of migration status, other informal barriers (e.g., cultural and barriers to information access) might explain lower RIRs in immigrant women, especially recent immigrants and those from HMPC in sub-Saharan Africa and Asia. Further investigations are needed to identify obstacles and appropriate promotion and access-enabling strategies for rubella immunization.

Differences in Influenza Vaccination Coverage between Adult Immigrants and Italian Citizens at Risk for Influenza-Related Complications: A Cross-Sectional Study

BACKGROUND

Due to their increased vulnerability, immigrants are considered a priority group for communicable disease prevention and control in Europe. This study aims to compare influenza vaccination coverage (IVC) between regular immigrants and Italian citizens at risk for its complications and evaluate factors affecting differences.

METHODS

Based on data collected by the National Institute of Statistics during a population-based cross-sectional survey conducted in Italy in 2012-2013, we analysed information on 42,048 adult residents (≥ 18 years) at risk for influenza-related complications and with free access to vaccination (elderly residents ≥ 65 years and residents with specific chronic diseases). We compared IVC between 885 regular immigrants and 41,163 Italian citizens using log-binomial models and stratifying immigrants by area of origin and length of stay in Italy (recent: < 10 years; long-term: ≥ 10 years).

RESULTS

IVC among all immigrants was 16.9% compared to 40.2% among Italian citizens (vaccination coverage ratio (VCR) = 0.42, 95% confidence interval (CI): 0.36-0.49). Adjusting for sex, age and area of residence, this difference was greatly reduced but remained statistically significant (VCR = 0.71, 95 CI: 0.61-0.81). Further adjustment for socio-economic factors (education, occupation, family composition and economic status) and a composite indicator of health-services utilization did not affect the difference (VCR = 0.78, 95% CI: 0.68-0.90). However, after adjustments, only long-term immigrants from Africa (VCR = 0.49, 95% CI: 0.28-0.85) and recent immigrants (VCR = 0.58, 95% CI: 0.43-0.78) showed a significantly different IVC compared to Italian citizens.

CONCLUSIONS

Differences in demographic characteristics, socio-economic conditions and health-services utilization explained the reduced IVC in most long-term immigrants compared to Italian citizens. By contrast, these differences did not explain the reduced IVC in long-term immigrants from Africa and recent immigrants. This suggests that IVC in these sub-groups is affected by other informal barriers (e.g., cultural and linguistic) that need to be investigated to promote effective immunization access strategies.

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.

Impact of vaccination on invasive pneumococcal disease in adults with focus on the immunosuppressed

Pneumococcal conjugate vaccine (PCV13) has been recently added to the vaccine recommendations for immunosuppressed adults (ISP). We conducted a multicenter observational prospective study aimed to assess the evolving epidemiology of invasive pneumococcal disease (IPD) in adults, with especial focus on ISP. All IPD cases admitted from 1999 to 2014 were included. ISP was defined as patients on current cancer chemotherapy, immunosuppressive therapy for autoimmune disease, biological therapy, chronic systemic steroid use, hemodialysis, neutropenia or HIV infection. A total of 799 IPD episodes were analyzed, 198 were considered ISP. IPD incidence decreased from 20 to 8/100,000-population year (p < 0.004) over the study period. No changes in mortality were observed. Penicillin resistance experienced a significant decline. In 694 episodes the serotype was known. Global vaccine coverage considering the whole study period, was for PCV7 21.6% vs. 28.8% in general and in immunosuppressed population (p = 0.04) and for PCV13 64.5% and 56.6% respectively (p = 0.05). The proportion of IPD isolates included in PCV7 and PCV13 significantly decreased over time. A reduction in the incidence of IPD in adults was seen late after the vaccine licensure, both in general population and in ISP. Coverage of PCV13 vaccine might be suboptimal for ISP in the coming years.

The financial crisis and the expected effects on vaccinations in Europe: a literature review

Starting in 2008 several European countries experienced a financial crisis. Historically, diseases whose prevention and treatment depend highly on the continuity of healthcare re-emerge during political and financial crises. Evidence suggests that the current financial crisis has had an impact on the health and welfare of Europeans and that population health status and morbidity as well as mortality patterns may change in the coming years. At the same time decisions about expenditure for health services may impact the ability of public health providers to respond. It is expected that the current crisis will further exacerbate socioeconomic and health inequalities and novel vulnerable groups will emerge in addition to existing ones. We review the available evidence and discuss how the current crisis may have an impact on vaccine-preventable diseases and influence vaccination coverage rates in Europe.

Effects of immunocompromise and comorbidities on pneumococcal serotypes causing invasive respiratory infection in adults: implications for vaccine strategies

BACKGROUND

The 13-valent pneumococcal conjugate vaccine (PCV13) has recently been approved for use in immunocompromised adults. However, it is unclear whether there is an association between specific underlying conditions and infection by individual serotypes. The objective was to determine the prevalence of serotypes covered by PCV13 in a cohort of patients with invasive pneumococcal disease of respiratory origin and to determine whether there are specific risk factors for each serotype.

METHODS

An observational study of adults hospitalized with invasive pneumococcal disease in 2 Spanish hospitals was conducted during the period 1996-2011. A multinomial regression analysis was performed to identify conditions associated with infection by specific serotypes (grouped according their formulation in vaccines and individually).

RESULTS

A total of 1094 patients were enrolled; the infecting serotype was determined in 993. In immunocompromised patients, 64% of infecting serotypes were covered by PCV13. After adjusting for age, smoking, alcohol abuse, and nonimmunocompromising comorbidities, the group of serotypes not included in either PCV13 or PPV23 were more frequently isolated in patients with immunocompromising conditions and cardiopulmonary comorbidities. Regarding individual serotypes, 6A, 23F, 11A, and 33F were isolated more frequently in patients with immunocompromise and specifically in some of their subgroups. The subgroup analysis showed that serotype10A was also associated with HIV infection.

CONCLUSIONS

Specific factors related to immunocompromise seem to determine the appearance of invasive infection by specific pneumococcal serotypes. Although the coverage of serotypes in the 13-valent conjugate pneumococcal vaccine (PCV13) was high, some non-PCV13-emergent serotypes are more prevalent in immunocompromised patients.

Epidemiology of two large measles virus outbreaks in Catalonia: what a difference the month of administration of the first dose of vaccine makes

Measles cases in the European Region have been increasing in the last decade; this illustrates the challenge of what we are now encountering in the form of pediatric preventable diseases. In Catalonia, autochthonous measles was declared eliminated in the year 2000 as the result of high measles-mumps-rubella vaccine (MMR) coverage for first and second dose (15 mo and 4 y) since the mid-1990s. From then on, sporadic imported cases and small outbreaks appeared, until in 2006-2007 a large measles outbreak affecting mostly unvaccinated toddlers hit the Barcelona Health Region. Consequently, in January 2008, first dose administration of MMR was lowered from 15 to 12 mo of age. A new honeymoon period went by until the end of 2010, when several importations of cases triggered new sustained transmission of different wild measles virus genotypes, but this time striking young adults. The aim of this study is to show the effect of a change in MMR vaccination schedule policy, and the difference in age incidence and hospitalization rates of affected individuals between both outbreaks.   Epidemiologic data were obtained by case interviews and review of medical records. Samples for virological confirmation and genotyping of cases were collected as established in the Measles Elimination plan guidelines. Incidence rate (IR), rate ratio (RR) and their 95% CI and hospitalization rate (HR) by age group were determined. Statistic z was used for comparing proportions. Total number of confirmed cases was 305 in the 2010 outbreak and 381 in the 2006-2007 outbreak; mean age 20 y (SD 14.8 y; 3 mo to 51 y) vs. 15 mo (SD 13.1 y; 1 mo to 50 y). Highest proportion of cases was set in ≥ 25 y (47%) vs. 24.2% in 2006 (p < 0.001). Differences in IR for ≤ 15 mo (49/100,000 vs. 278.2/100,000; RR: 3,9; 95%CI 2,9-5.4) and in overall HR 29.8% vs. 15.7% were all statistically significant (p < 0.001). The change of the month of age for the administration of the first MMR dose proved successful to protect infants. Yet, given the current epidemiological situation, continued awareness and efforts to reach young adult population, especially those at high risk of infection and transmission such as healthcare workers and travelers, are needed to stop the spread of the virus when importations occur.

Results of the rubella elimination program in Catalonia (Spain), 2002-2011

Rubella is usually a mild disease with nonspecific symptoms, but can cause congenital rubella syndrome (CRS) when infection occurs during pregnancy. The objective of this study was to evaluate the sensitivity and positive predictive value of different data sources used for surveillance purposes in the Rubella Elimination Program of Catalonia between 2002 and 2011. The Urgent Notification to the Statutory Disease Reporting System, the Individualized Disease Reporting System, screening for other viruses included in the Measles Elimination Program, the Microbiological Reporting System and the Minimum Hospital Discharge Data were evaluated. 100 suspected cases of postnatal rubella and 6 suspected cases of CRS were detected. For postnatal rubella, Urgent Notification had the highest sensitivity (32.5%; 95%CI 18.6-49.1), followed by the Virus screening in Measles Elimination Program (25%; 95%CI 12.7-41.2). Virus screening in the Measles Elimination Program had the highest PPV (76.9%; 95%CI 46.1-94.9), followed by the Individualized Disease Reporting System (57.1%; 95%CI 28.9-82.3). For CRS cases, the Individualized Disease Reporting System had the highest sensitivity (100%, 95%CI 29.2-100) and the highest PPV (60%; 95%CI 14.7-100). Most confirmed postnatal cases (25 cases, 48.1%) were in the 25-44 y age group followed by the 15-24 y age group (11 cases, 21.2%). The highest values of sensitivity and PPV for the detection of confirmed cases corresponded to activities that were specifically introduced in the measles and rubella elimination programs.

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.

Increase in invasive nonvaccine pneumococcal serotypes at two hospitals in Barcelona: was replacement disease to blame?

AIM

To describe an increase in the incidence of invasive pneumococcal disease (IPD) caused by serotypes not contained in the heptavalent pneumococcal conjugate vaccine (PCV7) in children in two hospitals in Barcelona with different vaccine uptake.

METHODS

Cumulative incidences of IPD, vaccine and nonvaccine serotypes (NVSTs), and main clinical presentations before (1998-2001) and after vaccine introduction (2005-2008) were compared.

RESULTS

The incidence of IPD in children aged <2 years at Hospital Germans Trias i Pujol covering a population in which PCV7 was not widely used showed a nonsignificant increase from 29.9 to 58.8 per 100,000 child-years between both periods. Following vaccine introduction, there was a 2.5-fold increase in IPD caused by NVSTs in children aged <5 years. Analysis of trends in the almost fully vaccinated population of Hospital de Barcelona revealed a nonsignificant reduction in IPD incidence in children aged <2 years from 63.1 to 26.0 per 100,000 child-years. NVSTs in children aged <5 years showed a nonsignificant 1.7-fold increase in the vaccine period at this centre.

CONCLUSIONS

The paradoxical increase in invasive infections caused by NVSTs in these populations with different vaccine use suggests that these changes were not driven only by PCV7.

[Susceptibility to measles and varicella in healthcare workers in a tertiary hospital in Catalonia]

INTRODUCTION

To estimate the susceptibility to measles and varicella (chickenpox) in healthcare workers in a public tertiary level teaching hospital, in Catalonia.

METHODS

A prevalence study was conducted from January 2006 to December 2008 on 2,752 workers who had serology performed for the determination of measles or varicella by ELISA test during a health examination. Data were analysed by, sex, age, professional category and work unit.

RESULTS

A total of 153 healthcare workers were susceptible to measles and 187 to varicella. The susceptibility of healthcare workers to measles was 6.04% (95% CI: 5.78 to 6.30), and to varicella it was 7.45% (95% CI: 7.14 to 7.75). The highest susceptibility to measles was in resident physicians with 14% (95% CI: 10.8 to 18.5). In high-risk services, where highly immunocompromised patients are attended, the susceptibility of workers was slightly higher than the rest to measles (6.32% vs 5.93%) and varicella (8.34% vs 7.09%). Healthcare workers born after 1980 were 20 times (95% CI: 11.0 to 37.2) more likely to be susceptible to measles, and 2 times (95% CI: 1.2 to 3.2) more likely to be susceptible to varicella than those those born before 1965.

CONCLUSIONS

The susceptibility to measles in healthcare workers in our centre is higher in younger cohorts, with values higher than expected in a community with high vaccination coverage against measles, mumps, rubella vaccine (MMR) in the paediatric population for many years.

Epidemiology of pertussis in a country with high vaccination coverage

INTRODUCTION

Pertussis has been a preventable disease in Catalonia since 1965, but the annual number of cases remains high. The aim of this study was to analyze the epidemiology of pertussis in Catalonia and its implications for control purposes.

METHODS

An epidemiological study was carried out in Catalonia between 2004 and 2008. Pertussis cases reported to the Department of Health were collected and disease reports were filled out with the case information. Incidence rates, rate ratios (RR) and their 95% confidence intervals (CI) were calculated.

RESULTS

963 cases were reported: 555 (57.6%) were confirmed and 408 (42.4%) were suspected cases. The reported incidence rate was 2.01 × 10(-5) person years in 2004 and 4.34 in 2008. The biggest increase in cases between 2004 and 2008 was observed in the ≥35 years age group (RR: 6.98; 95%CI: 2.11-36.36). 303 (31.5%) patients were hospitalized, of whom 93.7% were aged <1 year. Clinical differences were observed in paroxysmal cough (83.8% in suspected and 76.4% in confirmed cases, p=0.005), posttussive vomiting (47.1% and 36.1%, respectively, p=0.001), apnoea (13.7% and 21.3%, respectively, p=0.003) and fever (20.1% and 12.4%, respectively, p=0.001).

CONCLUSION

Pertussis incidence rates increased during the study period, with the greatest increase occurring in the ≥35 years age group. A booster dose of vaccine in young people could reduce the circulation of B. pertussis in adolescents and adults and indirectly reduce the incidence in children.

Religious subgroups influencing vaccination coverage in the Dutch Bible belt: an ecological study

Background

The Netherlands has experienced epidemics of vaccine preventable diseases largely confined to the Bible belt, an area where -among others- orthodox protestant groups are living. Lacking information on the vaccination coverage in this minority, and its various subgroups, control of vaccine preventable diseases is focused on the geographical area of the Bible belt. However, the adequacy of this strategy is questionable. This study assesses the influence of presence of various orthodox protestant subgroups (orthodox protestant denominations, OPDs) on municipal vaccination coverage in the Bible belt.

Methods

We performed an ecological study at municipality level. Data on number of inhabitants, urbanization level, socio-economical status, immigration and vaccination coverage were obtained from national databases. As religion is not registered in the Netherlands, membership numbers of the OPDs had to be obtained from church year books and via church offices. For all municipalities in the Netherlands, the effect of presence or absence of OPDs on vaccination coverage was assessed by comparing mean vaccination coverage. For municipalities where OPDs were present, the effect of each of them (measured as membership ratio, the number of members proportional to total number of inhabitants) on vaccination coverage was assessed by bivariate correlation and multiple regression analysis in a model containing the determinants immigration, socio-economical status and urbanization as well.

Results

Mean vaccination coverage (93.5% ± 4.7) in municipalities with OPDs (n = 135) was significantly lower (p < 0.001) than in 297 municipalities without OPDs (96.9% ± 2.1). Multiple regression analyses showed that in municipalities with OPDs 84% of the variance in vaccination coverage was explained by the presence of these OPDs. Immigration had a significant, but small explanatory effect as well. Membership ratios of all OPDs were negatively related to vaccination coverage; this relationship was strongest for two very conservative OPDs.

Conclusion

As variance in municipal vaccination coverage in the Bible belt is largely explained by membership ratios of the various OPDs, control of vaccine preventable diseases should be focused on these specific risk groups. In current policy part of the orthodox protestant risk group is missed.

Mumps vaccine effectiveness in highly immunized populations

The aim of the study was to investigate effectiveness of mumps MMR component in communities with high MMR coverage. Outbreak-related cases of mumps born between 1995 and 2005 notified to Navarre and Catalonia public health services during the period 2005-2007 were studied. Vaccine effectiveness (VE) and their 95%CI were calculated using the screening method. Of 47 confirmed, 85.1% immunized with at least one dose (1MMR) and 44.9% with two (2MMR). Estimated VE was 85.4% (95%CI: 67.3-93.4) for 1MMR and 88.5% (95%CI: 78.1-93.9) for 2MMR. High 2MMR coverage, improved confirmation techniques and further VE studies with all confirmed cases are needed to prevent further outbreaks.

Measles risk groups in Spain: implications for the European measles-elimination target

The European Region has set itself the goal of eliminating measles by 2010. Incidence has increased in recent years. This study sought to investigate outbreaks in Spain in the period 2005-2007, in order to identify measles-vulnerable groups and compare Spain to other European countries which have also had measles outbreaks. The pattern observed for Spain proved different to that of other European countries, i.e., whereas young adults and infants aged under 15 months were affected in Spain, children aged under 9 years comprised the predominant group in other European countries. Measles cases in Spain reflect low coverage when vaccination began, a pattern that could be repeated in neighbouring countries. Vaccination efforts should thus be targeted at vulnerable groups, namely: young adults; health professionals; travelling communities; and adopted infants and foreigners from countries with important pockets of susceptibles.

Vaccination coverage against measles in German-born and foreign-born children and identification of unvaccinated subgroups in Germany

Data from the representative German Health Interview and Examination Survey for Children and Adolescents were used to identify unvaccinated subgroups that should be targeted by vaccination programmes in order to interrupt measles transmission. Measles vaccination coverage was low among children below the age of 3, having > or =3 siblings and in foreign-born migrants. Multivariate analyses show that vaccination coverage was strongly related to the place of birth in migrants: foreign-born children have a three-fold odds of being unvaccinated. Odds were also higher in children living in former West Germany, having > or =3 siblings, and it was especially high in children with parents reporting reservations against vaccinations.

Large outbreak of measles in a community with high vaccination coverage: implications for the vaccination schedule

BACKGROUND

Attempts to eliminate measles from a country or region may be disrupted by an imported case that affects indigenous persons. The objective of this study was to analyze epidemiological and clinical characteristics of a measles outbreak in Catalonia, Spain, in 2006.

METHODS

Data on cases of measles reported to the Department of Health, Generalitat of Catalonia, during the period 28 August 2006 through 8 July 2007 were collected. Suspected cases were confirmed by determination of measles-specific immunoglobulin M antibodies and/or detection of virus genome. Incidences were calculated using the estimated population of Catalonia for 2006, and 95% confidence intervals were determined assuming a Poisson distribution. The association between proportions was determined using the chi(2) test and Fisher's exact test. The level of statistical significance was set at alpha = .05.

RESULTS

A total of 381 cases were confirmed, for an incidence of 6.6 cases per 100,000 persons. A total of 89.5% of cases occurred in nonvaccinated persons, mainly those aged < or =15 months (incidence, 278.2 cases per 100,000 persons; mean age of patients, 12 months). Indigenous subjects accounted for 89.8% of cases, and laboratory confirmation of results was obtained for 87.1%. Measles genotype D4 was identified in all sequenced samples.

CONCLUSIONS

The age distribution of cases of measles among children aged <15 months suggests that the first dose of vaccine should be routinely administered at the age of 12 months.

Epidemiology of hepatitis A before and after the introduction of a universal vaccination programme in Catalonia, Spain

A universal vaccination program for preadolescents, aged 12 years, with the hepatitis A + B vaccine was introduced in 1998 in Catalonia (Spain) with the aim of protecting the whole population against hepatitis A. The hepatitis A + B vaccine program replaced the hepatitis B vaccination program for preadolescent started in 1991. The impact of the hepatitis A + B vaccination program was studied by assessment of the trend of reported cases of hepatitis A. All cases of viral hepatitis reported from 1992 to 2006 were included in the study. To evaluate changes in the epidemiology of hepatitis A, two periods were considered: a prevaccination period (1992-1998) and a post-vaccination period (2001-2006). The ratios of the rates were calculated according to age and sex. The comparison of rates and proportions was made by calculation of the normal z statistic. A total of 7536 cases of viral hepatitis were reported, of which 4109 (54.52%) were hepatitis A. The incidence rate of hepatitis A fell from 5.44 per 100 000 person-years in the prevaccination period to 3.02 in the post-vaccination period. In males, the rate fell from 6.85 to 3.89 and in females from 4.10 to 2.18. The male-female ratio of incidence rates was lower in the post-vaccination period. In males the global decline of incidence rate was 43.26% and in females 46.96%. The greatest decline occurred in the 15 to 19 years age group in both sexes (79.1% in men and 78.34% in women) but declines in the 10-14 years age group were also very important (69.21% and 67.88%, respectively). In conclusion, hepatitis A incidence fell in Catalonia in the post-vaccination period in vaccinated adolescents and also in other unvaccinated groups who have benefited from the indirect effects of the vaccination program.

A statistical model to estimate the impact of a hepatitis A vaccination programme

A program of routine hepatitis A+B vaccination in preadolescents was introduced in 1998 in Catalonia, a region situated in the northeast of Spain. The objective of this study was to quantify the reduction in the incidence of hepatitis A in order to differentiate the natural reduction of the incidence of hepatitis A from that produced due to the vaccination programme and to predict the evolution of the disease in forthcoming years. A generalized linear model (GLM) using negative binomial regression was used to estimate the incidence rates of hepatitis A in Catalonia by year, age group and vaccination. Introduction of the vaccine reduced cases by 5.5 by year (p-value<0.001), but there was a significant interaction between the year of report and vaccination that smoothed this reduction (p-value<0.001). The reduction was not equal in all age groups, being greater in the 12-18 years age group, which fell from a mean rate of 8.15 per 100,000 person/years in the pre-vaccination period (1992-1998) to 1.4 in the vaccination period (1999-2005). The model predicts the evolution accurately for the group of vaccinated subjects. Negative binomial regression is more appropriate than Poisson regression when observed variance exceeds the observed mean (overdispersed count data), can cause a variable apparently contribute more on the model of what really makes it.

Seroprevalence of varicella zoster virus infection in child and adult population of Catalonia (Spain)

The aim of this study was to determine the prevalence of varicella IgG antibodies in the population of Catalonia, and the variables associated. The study was carried out in 2002 in a representative sample of juvenile (5-14 years) and adult population (> or =15 years) of Catalonia (Spain). The global prevalence determined by ELISA test was 95.5% (95% CI 94.7-96.3). The prevalence increased with age, from 82% (95% CI 77.0-87.0) in the 5-9 years age up to 99.4% (95% CI 98.2-100) in >64 years of age. No statistically significant differences in the seroprevalence according to the sociodemographic variables were observed. The current strategy of vaccinating preadolescents at 12 years of age who have not suffered the disease will require more than 30 years to cover the current gap immunity in adolescents and young adults. Vaccination with two doses of vaccine for all adolescents and adults < or = 50 years who report not having suffered the disease during childhood should be considered.