To assess the clinical characteristics and direct health costs associated with pertussis cases reported to and confirmed by epidemiological services and cases detected among household contacts in Catalonia (Spain) in 2012–2013.

We aimed to investigate transmission rates of pertussis in household contacts of cases and factors associated with transmission. A prospective epidemiological study was conducted in 2012 and 2013 to determine the incidence of pertussis among household contacts of reported cases in Catalonia and Navarre, Spain. An epidemiological survey was completed for each case and contact, who were followed for 28 days to determine the source of infection (primary case) and detect the occurrence of secondary cases. Odds ratios (ORs) were used to estimate the effectiveness of vaccination and chemoprophylaxis in preventing new cases, using the formula (1 -OR) x 100. For the 688 primary cases, a total of 2,852 contacts were recorded. The household transmission rate was 16.1% (459/2,852) and rose according to the age (> 18 years) and lack of immunisation of the primary cases, and also the age (0-18 years), family relationship (siblings and children), lack of vaccination and chemoprophylaxis of contacts. Pertussis vaccine effectiveness in preventing new cases was 65.0% (95% confidence interval (CI): 11.6 to 86.2) for full vaccination (>= 4 doses) and 59.7% (95% CI: -6.8 to 84.8) for incomplete vaccination (< 4 doses). The effectiveness of chemoprophylaxis was 62.1% (95% CI: 40.3 to 75.9). To reduce household transmission, contacts should be investigated to detect further cases and to administer chemoprophylaxis. The current vaccination status of cases and contacts can reduce household transmission.

Pertussis vaccination with 4–5 doses of acellular vaccines is recommended in Spain to all children at 2 months to 6 years of age. The effectiveness of the acellular pertussis vaccination was assessed in this study by comparing the incidence of secondary pertussis in vaccinated (4–5 doses) and unvaccinated or partially vaccinated (0–3 doses) household contacts 1–9 years old of confirmed cases of pertussis in Spain in 2012–13. Eighty-five percent of contacts had been vaccinated with 4–5 doses of acellular pertussis vaccines. During the 2-year study period, 64 cases of secondary pertussis were detected among 405 household contacts 1–9 years old: 47 among vaccinated and 17 among unvaccinated or partially vaccinated contacts. The effectiveness for preventing secondary pertussis, calculated as 1 minus the relative risk (RR) of secondary pertussis in vaccinated vs. unvaccinated/partially vaccinated contacts, was 50 % [95 % confidence interval (CI): 19–69 %, p < 0.01] when household contacts were vaccinated using DTaP, Tdap, hexavalent or heptavalent vaccines, and it was 51.3 % (95 % CI: 21–70 %, p < 0.01) when they were vaccinated using DTaP or TdaP vaccines. The effectiveness adjusted for age, sex, pertussis chemotherapy and type of household contact was 58.6 % (95 % CI: 17–79 %, p < 0.05) when contacts were vaccinated using available acellular vaccines, and it was 59.6 % (95 % CI: 18–80 %, p < 0.01) when they were vaccinated using DTaP vaccines. Acellular pertussis vaccination during childhood was effective for preventing secondary pertussis in household contacts 1–9 years old of pertussis cases in Catalonia and Navarra, Spain.

Non-immune neonates and non-immune pregnant women are at risk of developing rubella, measles and mumps infections, including congenital rubella syndrome. We describe the seroepidemiology of measles, mumps and rubella (MMR) in neonates and pregnant women in Catalonia (Spain). Anti-rubella, anti-measles and anti-mumps serum IgG titres were assessed using enzyme-linked immunosorbent assay (ELISA) tests in 353 cord blood samples from neonates of a representative sample of pregnant women obtained in 2013. The prevalence of protective antibody titres in neonates was 96 % for rubella IgG (≥8 IU/ml), 90 % for measles IgG (>300 IU/ml) and 84 % for mumps IgG (>460 EU/ml). Slightly lower prevalences of protective IgG titres, as estimated from the cord blood titres, were found in pregnant women: 95 % for rubella IgG, 89 % for measles IgG and 81 % for mumps IgG. The anti-measles and anti-mumps IgG titres and the prevalences of protective IgG titres against measles and mumps increased significantly (p < 0.001) with maternal age. The prevalence of protective anti-measles IgG titres decreased by 7 % [odds ratio (OR) = 0.15, p < 0.001), the prevalence of protective anti-rubella IgG titres increased by 3 % (OR = 1.80, p < 0.05) and the MMR vaccination coverage (during childhood) in pregnant women increased by 54 % (OR = 2.09, p < 0.001) from 2003 to 2013. We recommend to develop an MMR prevention programme in women of childbearing age based on mass MMR vaccination or MMR screening and vaccination of susceptible women to increase immunity levels against MMR.

Herd immunity blocks the transmission of measles, mumps and rubella in a population group when the prevalence of positive serologic results (p) is higher than a critical value (p c), known as the herd immunity threshold. A new preventive strategy should be developed in order to achieve the elimination of measles, rubella and mumps in Europe based on the serological assessment of herd immunity levels in different population groups. This strategy could detect population groups without herd immunity (p < p c) and indicate the additional vaccination coverage required in these groups in order to establish herd immunity and prevent outbreaks. The serological assessment of herd immunity levels in Catalonia, Spain, showed that herd immunity had not been established for measles and mumps in schoolchildren (5-9 years of age) and youths/younger adults (15-29 years of age), and that the additional vaccination coverage required to establish herd immunity in these groups was 1-7%. The new preventive strategy should be used to detect priority population groups for preventive and surveillance activities in European countries.

A survey of the seroprevalence of pertussis antibodies in a representative sample of the population from Catalonia was carried out. Ninety-seven municipalities and 30 schools were randomly selected to recruit the 2126 subjects who participated in the study. A serum sample was obtained from all individuals participating in the study in order to determine levels of pertussis toxin (PT) and filamentous hemagglutinin (FHA) antibodies by ELISA test. Sociodemographic data were collected for all subjects. The prevalence of PT antibodies was 75% and that of FHA antibodies 89%. Significant increments were observed with age, both in the prevalence of PT (P < 0.0001) and of FHA (P = 0.018). Of the sociodemographic variables studied, only urban habitat was significantly associated to PT antibodies. The agreement observed among the two types of antibodies studied was weak (K = 0.264). Routine revaccination with the acellular vaccine in children over 7 years of age, in adolescents and adults seems a reasonable strategy to prevent the appearance of cases of pertussis in the community.

Objective The objective of this study was to determine the prevalence of antibodies against varicella‐zoster virus (VZV) in pregnant women in Catalonia (Spain).Setting The prevalence of antibodies against VZV was assessed in a representative sample (n= 1522) of pregnant women of Catalonia obtained in 2003.Method The sample was obtained including all women attended for childbirth, during 2 months of 2003, in 27 randomly selected hospitals with maternity clinics.Main outcome measures Varicella‐zoster antibodies were determined using the enzyme‐linked immunosorbent assay test.Results The total number of women included in the study was 1522, corresponding to a participation rate of 83%. The prevalence of varicella‐zoster antibodies in pregnant women was 96.1% (95% CI 95.1–97.1). The prevalence of antibodies was 94% in pregnant women aged 15–24 years, 95% in those aged 25–29 years and >95% in those aged 30–49 years. The prevalence of antibodies was not associated to the place of birth, place of residence (urban or rural), educational level and social class. The study showed that 6% of pregnant women aged 15–24 years and 5% of those aged 25–29 years were susceptible to varicella‐zoster infections in Catalonia (Spain).Conclusion The study showed that a varicella‐zoster vaccination programme aimed at women of childbearing age could be necessary in Catalonia to prevent all varicella‐zoster infections during pregnancy.

Aims: To analyze the prevalence of hepatitis B virus infection markers and hepatitis B vaccination in a representative sample of the juvenile and adult population of Catalonia and to evaluate the changes with respect to seroepidemiological surveys carried out in 1989 and 1996.Design: In all subjects anti-HBc and anti-HBs antibodies and HBsAg were determined using an ELISA test. The possible association between sociodemographic variables and the prevalence of markers was analysed by calculating the adjusted odd ratio (simple logistic regression).Setting: The study was carried out in 2002 in representative samples of the juvenile (5-14 years) and adult population(>= 15 years) of Catalonia (Spain).Main results: In 2002 the global prevalence of HBsAg+ was 0.7% (95% CI: 0.4-1.0) and that of anti-HBc+ 8.7% (95% CI: 7.6-9.8), values higher than those obtained in 1989 of 1.5% (95% CI: 1.0-2.1) and 15.6 (95% CI: 13.9-17.3). The prevalence of markers of infection increased with age. The only sociodemographic variable significantly associated with the prevalence of hepatitis B virus infection was the place of birth. The risk of infection was twice as high in subjects born outside Catalonia (p<0.01), adjusted OR 2.0 (95% CI: 1.34-2.98) compared with those born in Catalonia.Conclusions: The results of this study show that the prevalence of hepatitis B virus infection (anti-HBc+) in Catalonia (Spain) is currently the lowest it has ever been and suggest that there has been a change in the pattern of endemicity of hepatitis B virus infection in Catalonia, which has become a country of low endemicity. (c) 2007 Elsevier Ltd. All rights reserved.

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 (≥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.

Investigar la validez del antecedente de vacunación antihepatitis B obtenido en la primera visita al tocólogo de las mujeres embarazadas. En una muestra representativa de mujeres embarazadas de Cataluña (n = 1.538), se ha comparado el antecedente de vacunación antihepatitis B obtenido mediante interrogatorio durante la primera visita al tocólogo con el obtenido mediante el análisis serológico de marcadores de vacunación anti-HBs+ anti-HBc−. Las prevalencias de antecedente de vacunación antihepatitis B obtenidas mediante interrogatorio fueron sensiblemente más bajas que las obtenidas mediante análisis serológico en todos los grupos de edad. Las diferencias fueron especialmente importantes en las mujeres más jovenes (odds ratio [OR] = 11,42, en el grupo de edad de 15 a 19 años, y 2,17, en el de 20 a 24 años). La evaluación de la cobertutra vacunal antihepatitis B mediante el análisis de marcadores serológicos (anti-HBs+ y anti-HBc−) es mucho más fiable que la realizada mediante interrogatorio. To study the validity of hepatitis B vaccination history in pregnant women obtained at the first visit to the obstetrician. The hepatitis B vaccination history obtained at the first visit to the obstetrician was compared with the results of serological analysis of vaccination markers (antiHBs+, antiHBc-) in a representative sample of pregnant women in Catalonia (n = 1,538) in Spain. The prevalence of hepatitis B vaccination obtained by history taking was substantially lower than that shown by serological analysis in all age groups. The differences were more marked in younger women (OR: 11.42 in the group aged 15-19 years and 2.17 in that aged 20-24 years). Evaluation of hepatitis B vaccination coverage by serology (antiHBs+ and antiHBc-) is much more reliable than information given by pregnant women during history taking at the first visit.

The objective of this study was to investigate the prevalence of hepatitis A antibodies (anti-HAV) in schoolchildren in Catalonia and to compare it with the rates found in previous studies. Sera from a representative sample of 1,342 children aged between 6 and 15 years, recruited in 2001, were tested for anti-HAV. The results were related to sociodemographic variables and vaccination history. The overall prevalence of anti-HAV was 51.4%. The prevalence was 5.5% in non-vaccinated children, similar to that found in a 1996 study, and 96.6% in vaccinated children. The prevalence of anti-HAV in non-vaccinated children increased significantly with age, reaching 11.6% in the 13-15 years age group. The prevalence of anti-HAV was higher in children born outside Catalonia than in those born in Catalonia (16.1% vs. 5.0%, P = 0.02). The expected continuation in the decline in the prevalence of anti-HAV in non-vaccinated schoolchildren, observed in Catalonia since 1986, was not found in 2001. The rate of anti-HAV in 2001 was slightly higher than in 1996, although the difference was not statistically significant (5.5 and 3.5%, respectively). This could be explained by the increased number of recent immigrant children born outside Catalonia, mainly in countries where hepatitis A is highly endemic.

Objetivo: La vacunación antineumocócica es un procedimiento efectivo para prevenir la neumonía neumocócica. En este estudio se ha evaluado el coste-efectividad de las estrategias de vacunación antineumocócica (23 serotipos) en la población de 5 o más años de Cataluña. Métodos: El coste-efectividad se ha evaluado en términos de coste por año de vida ganado (AVG), comparando el coste neto del programa vacunal con su efectividad. El coste neto del programa vacunal se calculó restando a los costes de vacunar al 70% de la población la reducción de los costes sanitarios de la neumonía neumocócica que se puede conseguir con la vacunación. Los costes de vacunación se estimaron teniendo en cuenta un precio de 11,51 euros (1.915 ptas.) para la vacuna antineumocócica. Los costes y beneficios del programa vacunal se actualizaron para el año 1996 utilizando una tasa de descuento del 5%. Resultados: Se obtuvo una razón coste-efectividad de 9.023,27 euros por AVG para la vacunación universal de la población. El coste-efectividad fue de 113.177,12 euros por AVG en los individuos de 5-24 años; de 19.482,51 euros por AVG en los de 25-44 años, de 7.122,80 euros por AVG en los de 45-64, e inferior a cero en los mayores de 65 años. En el grupo ≥ 65 años, la reducción de los costes de la enfermedad superaba los costes de vacunación con una razón ahorro:coste de 1,58. Los resultados del análisis coste-efectividad eran sensibles al precio de la vacuna, la eficacia vacunal y el porcentaje de neumonías causadas por el neumococo, siendo menos sensibles a los costes de la neumonía neumocócica la tasa de ingreso hospitalario en los pacientes con neumonías adquiridas en la comunidad y la cobertura vacunal. Conclusión: Los resultados de este estudio demuestran que la vacunación antineumocócica debería ser una intervención preventiva prioritaria en los individuos de 65 o más años y los de 45 a 64 años.Objectives: Pneumococcal vaccination is an effective procedure for preventing pneumococcal pneumonia. In this study we evaluate the cost-effectiveness of pneumococcal vaccination strategies (23 serotypes) in the population aged 5 years and older in Catalonia. Methods: Cost-effectiveness was evaluated in terms of cost per year of life gained (YLG) by comparing the net cost of the vaccination program with its effectiveness. The net cost of the vaccination program was calculated by subtracting 70% of the population from the vaccination costs, representing the reduction in health costs due to pneumococcal pneumonia that can ve achieved with vaccination. Vaccination costs were estimated based on a price of 12.41 euros (1,915 ptas.) for pneumococcal vaccine. The costs and benefits of the vaccination program were updated for 1996 by using a discount rate of 5%. Results: A cost-effectiveness ratio of 9,023.27 euros per YLG was achieved for universal vaccination of the population. Cost-effectiveness was 11,3177.12 euros per YLG in individuals aged 5-24 years, 19,482.51 euros per TLG in those aged 25-44 years, 7,122.80 euros per YLG in those aged 45-64 years and less than 0 in those aged 65 years and older. In this group the reduction in cost of the disease was greater than the vaccination costs with a cost-benefit ratio of 1.58. The results of the cost-efecctiveness analysis were sensitive to vaccine costs and efficacy and the percentage of pneumonias caused by pneumococcus but were less sensitive to the costs of pneumococcal pneumonia, the rate of hospital admission among patients with community-acquired pneumonia and vaccine coverage. Conclusion: The results of this study show that pneumococcal vaccination should be a priority in individuals aged 65 years and older and in those aged 45-64 years.

To investigate the prevalence of mumps antibodies in a representative sample of the Catalan population and compare the results with those obtained previously. The study was carried out in 1996 in representative samples of the schoolchild (6-14 years) and adult (> 15 years) population of Catalonia. Thirthy schools and 97 municipalities in Catalonia were selected by random cluster sampling. The presence of mumps antibodies was determined in 895 schoolchildren and 1,258 adults using an ELISA technique. In all cases, age, gender, place of birth, place of residence, educational level and social class were studied. The overall prevalence of mumps antibodies was 89.5%. No relationship was found between this prevalence and the socio-demographic variables studied. In schoolchildren vaccination coverage was 91.2% (95% CI: 89.3-93). In the 6-7 years age group the prevalence was 81.7% (95% CI: 77.0-86.4), which was significantly higher than that observed in 1992. In Catalan schoolchildren, the prevalence of mumps antibodies is higher than that found in children from other Spanish communities and comparable countries. Although the figures have improved with respect to 1992, the data from this seroprevalence study show that children in the 6-7 years age group have the worst protection. Advancing the second dose of the combined MMR vaccine to 4 years of age, as has been done since 1999, may improve this situation. Investigar la prevalencia de anticuerpos antiparotiditis en una muestra representativa de la población de Cataluña y comparar los resultados con los obtenidos previamente. El estudio se realizó en 1996 en muestras representativas de la población escolar (6-14 años) y adulta (> 15 años) de Cataluña. Se seleccionaron 30 escuelas y 97 municipios de Cataluña mediante un muestreo aleatorio estratificado por clusters. Se determinó mediante test de ELISA la presencia de anticuerpos antiparotiditis en 895 escolares y 1.258 adultos, y se investigaron en todos ellos la edad, el sexo, el lugar de nacimiento, el lugar de residencia, el nivel de estudios y la clase social. La prevalencia global de anticuerpos antiparotiditis fue del 89,5%, sin que se observara asociación de dicha prevalencia con ninguna de las variables sociodemográficas estudiadas. En los escolares, la cobertura vacunal fue del 91,2% (intervalo de confianza [IC] del 95%: 89,4-93), observándose en el grupo de 6-7 años una prevalencia del 81,7% (IC del 95%: 77,0-86,4), que resultó significativamente superior a la detectada en 1992. En los escolares de Cataluña la prevalencia de anticuerpos antiparotiditis es superior a la de otras comunidades y países de nuestro entorno. Aunque se ha mejorado respecto a la situación de 1992, los datos de esta encuesta de seroprevalencia ponen de manifiesto que los escolares de 6-7 años son los peor protegidos. El adelanto de la segunda dosis de la vacuna triple vírica a los 4 años de edad que se viene realizando desde 1999 puede contribuir a mejorar esta situación.

Investigar el estado inmunitario frente a la rubéola de la población infantil y adulta de Cataluña en el año 1996 y comparar los resultados obtenidos con los de encuestas seroepidemiológicas anteriores. Se ha determinado la presencia de anticuerpos antirrubéola en una muestra representativa (n = 1.258) de la población adulta (≥15 años) y de la población escolar de 6-7, 10-11 y 13-14 años (n = 895). La técnica utilizada ha sido la de ELISA. En los escolares, la prevalencia de anticuerpos antirrubéola aumenta con la edad, pasando del 87,5% a los 6-7 años al 92,2% a los 13-14 años. En los adultos, la prevalencia es del 96,6% a los 15-24 años, manteniéndose a un nivel similar en los grupos de más edad. No se observó ninguna asociación significativa de las variables sociodemográficas estudiadas con la prevalencia de anticuerpos. En la encuesta del año 1996 se observa un incremento estadísticamente significativo (p < 0,0001) en la prevalencia de anticuerpos en el grupo de edad de 6-7 años (87,5%), en relación con la de 1984 (61,8%). En los adolescentes y adultos la prevalencia de in munidad en 1996 fue similar a la encontrada en 1984. Los resultados del presente estudio indican que en 1996 la in munidad antirrubéolica era muy elevada en la población adulta en Cataluña, aunque todavía un pequeño porcentaje de las mujeres de edad fértil eran susceptibles de contraer la enfermedad. En los escolares existía un vacío de inmunidad del 12,5% en los niños de 6-7 años y del 8,4% en los de 11-14 años. Durante el período 1984-1996 se ha producido un importante incremento en la prevalencia de anticuerpos en el grupo de edad de 6-7 años (+15,7 puntos de porcentaje) al pasar del 61,8% en 1984 al 87,5% en 1996. En los demás grupos de edad escolar y en las mujeres en edad fértil, la prevalencia de inmunidad antirrubéola ha permanecido estacionaria. Estos datos sugieren que la circulación del virus de la rubéola todavía era importante durante los años ochenta y la primera mitad de los noventa en Cataluña. To investigate the level of immunity to rubella in the schoolchild and adult population of Catalonia in 1996 and to compare the results obtained with those of previous seroepidemiological surveys. The presence of rubella antibodies was determined in a representative sample (n = 1258) of the adult population (≥15 years) and the schoolchild population of 6-7, 10-11 and 13-14 years (n = 895). An ELISA technique was used. In schoolchildren, the prevalence of rubella antibodies increased with age, rising from 87.5% at 6-7 years to 92.2% at 13-14 years. In adults, the prevalence was 96.6% at 15-24 years, a level which was maintained in older age groups. No significant association between the socio demographic variables studied and the prevalence of antibodies was found. In the 1996 survey, a statistically significant increase (p < 0.0001) in the prevalence of antibodies in the 6-7 years age group (87.5%) was observed compared with that of 1984 (61.8%). In adolescents and adults, the prevalence of immunity in 1996 was similar to that found in 1984. The results of the present study show that in 1996 immunity to rubella was very high in the adult population of Catalonia, although a small percentage of fertile women were still susceptible to the disease. In schoolchildren, there was a gap in immunity of 12.5% in the 6-7 years age group and of 8.4% in the 11-14 years group. During the period 1984-1996 there was a substantial increase in the prevalence of antibodies in the 6-7 years age group (+15.7 percentage points), from 61.8% in 1984 to 87.5% in 1996. In the other schoolchild age groups and in fertile women, the prevalence of rubella immunity remained at the same levels. These data suggest that circulation of the rubella virus was still significant during the 1980s and the first half of the 1990s in Catalonia.

The objective of this study was to investigate the prevalence of antibodies against the hepatitis C virus (anti-HCV) and the associated risk factors in a representative sample of the population of Catalonia, Spain. Serum samples from 2,142 subjects aged between 5 and 70 years, selected at random from urban and rural habitats, were studied. Multiple logistic regression analysis was carried out to determine variables associated independently with the presence of HCV antibodies. The age and gender standardized prevalence of anti-HCV was 2.5% (95% confidence interval, 1.8-3.2). Prevalence increased significantly with age (P < 0.001), but no other sociodemographic variables were associated with HCV infection. Tattoos (OR: 6.2). blood transfusions (OR: 5.0) intravenous drug use (OR: 4.9) and antecedents of hospitalization (OR: 2.3) were variables associated independently with infection. HCV infection affects mainly elderly people in Spain and spares children and adolescents. This suggests that major exposure to HCV may have occurred many years ago, when infection was more widespread than in recent years. (C) 2001 Wiley-Liss, Inc.

The objective of this study was to investigate the prevalence of hepatitis B markers in a representative sample of 2142 subjects in Catalonia, Spain, and to compare it with previous studies. Multiple logistical regression analysis was carried out to determine variables associated with the markers studied. The prevalence of anti-HBc and HBsAg was 9.1% and 1.2%, respectively. Male gender, urban habitat, birth place outside Catalonia and lower social class were associated with the presence of anti-HBc. Carrier status was only associated with male gender. Between 1989 and 1996 there was a decrease of 46% in the prevalence of serum HBV markers mainly in the 25–44 (P<0.0001) and 35–64 year (P=0.0002) age groups, in those born in Catalonia (P=0.003) and in those in the higher social classes (P<0.0001). These decreases can be explained by the improved socioeconomic conditions and, partially, by the routine pre-adolescent and risk group programmes of immunization.