Effectiveness of acellular pertussis vaccination during childhood (<7 years of age) for preventing pertussis in household contacts 1-9 years old in Catalonia and Navarra (Spain).

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.

Clinical characteristics and pertussis costs in cases reported to epidemiological services and cases detected in household contacts in Catalonia (Spain).

PURPOSE: 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. METHODS: All pertussis cases confirmed by the epidemiological services (n = 641) and all cases detected among the household contacts (n = 422) were included in the study. The chi-square test and odds ratios were used to compare percentages and the t-test was used to compare mean pertussis costs, with p < 0.05 being considered statistically significant. RESULTS: Cases reported to epidemiological services had a higher percentage of hospitalizations (OR = 32.2, p < 0.001) and severe disease (OR = 27.7, p < 0.001) than cases detected among the household contacts. The total health costs associated with pertussis cases were €871,648, €799,704 (92 %) for cases reported to epidemiological services and €71,944 (8 %) for cases detected among the household contacts. Total treatment, detection, and quimiprophylaxis costs were € 809,702, € 44,312, and € 17,635, representing 92.5 %, 5.5 %, and 2 % of total pertussis costs respectively. The mean costs were significantly higher (p < 0.001) in cases reported to epidemiological services than in cases detected among the household contacts, for all cases (€1248 vs €170), and for severe (€4546 vs €1073), moderate (€204 vs €165), and mild (€153 vs €133) disease. CONCLUSIONS: The burden of pertussis in Catalonia was high in terms of health costs, especially in infants aged less than 1 year. Active epidemiological surveillance activities could prevent pertussis transmisison and reduce pertussis costs.

Prevalence of anti-rubella, anti-measles and anti-mumps IgG antibodies in neonates and pregnant women in Catalonia (Spain) in 2013: susceptibility to measles increased from 2003 to 2013.

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.

New preventive strategy to eliminate measles, mumps and rubella from Europe based on the serological assessment of herd immunity levels in the population.

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.

Declining prevalence of hepatitis B virus infection in Catalonia (Spain) 12 years after the introduction of universal vaccination.

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 (>or= 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.

Prevalence of varicella-zoster antibodies in pregnant women in Catalonia (Spain). Rationale for varicella vaccination of women of childbearing age.

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.

The seroepidemiology of tetanus in Catalonia, Spain.

Titres of anti-tetanus toxin antibodies > or = 0.1 IU/ml were determined using an enzyme linked immunosorbent assay in representative samples of the juvenile and adult population of Catalonia. The prevalence obtained in 1,316 juveniles and 1,296 adults was 99.4 and 68.3%, respectively. In adults, the prevalence in males (76.5%) was higher (P < 0.001) than in females (61.7%), fell with increasing age and was higher in subjects born in Catalonia (72.5%) than in those born outside Catalonia (57.9%) (P < 0.001). These results show that routine vaccination of children is successful. In adults aged > or = 45 years, the prevalence is inadequate and efforts should be made to increase vaccination.

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.

[Cost-effectiveness of 23-valent antipneumococcical vaccination in Catalonia (Spain)]. / Coste-efectividad de la vacunación antineumocócica 23-valente en Cataluña.

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.

Coste-efectividad de la vacunación antineumocócica 23-valente en Cataluña / Cost-effectiveness of 23-valent antipneumococcical vaccination in Catalonia, Spain

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 por ciento 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 por ciento. 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. (AU)

Community-based seroepidemiological survey of HCV infection in Catalonia, Spain.

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.

The seroepidemiology of B. pertussis infection in Catalonia, Spain.

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.

Seroepidemiology of varicella-zoster virus infection in Catalonia (Spain). Rationale for universal vaccination programmes.

With the aim of designing a strategy for vaccination against varicella-zoster virus (VZV), the results of a seroepidemiological survey on VZV infection carried out in a sample of the population of Catalonia are presented. Representative samples from schoolchildren (30 schools) and adults (97 municipal areas) were obtained by random cluster sampling. In the study, 883 children and 1253 adults were included. Age, gender, place of birth, place of residence, educational level and occupation were investigated in the study subjects. An ELISA test was used to measure varicella antibodies. The prevalence of varicella antibodies increased with age, being 85% in the 5-9 years age group, 92% in the 10-14 years age group, 94% in the 15-34 years age group and almost 100% in people over 35. No association was found between sociodemographic variables studied and prevalence levels of antibodies. These results suggest that the best vaccination strategy in Catalonia would be to add a temporary vaccination programme of pre-adolescents at 12 years to routine vaccination at 15 months.

Changes in the seroepidemiology of hepatitis B infection in Catalonia 1989-1996.

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.

[Changes in seroepidemiology of hepatitis A virus infection in Catalonia in the period 1989-1996. Implications for new vaccination strategy]. / Cambios en la seroepidemiología de la infección por el virus de la hepatitis A en Cataluña en el período 1989-1996. Implicaciones para una nueva estrategia vacunal.

BACKGROUND: The aim of this study was to investigate the prevalence of the risk factors of hepatitis A virus infection (HAV) in a representative sample of a Catalonian population obtained from 1995 to 1996 and the changes in the prevalence of this infection over the period of 1989-1996. SUBJECTS AND METHODS: The prevalence of anti-HAV was determined by an ELISA test in a randomized sample of 2,142 individuals, 884 from 6 to 14 years of age and 1,248 over the age of 15 years. The results were related to sociodemographic variables and multiple logistic regression analysis was performed to establish which variables were related to the risk of infection. RESULTS: The global prevalence of HAV infection was 67.8%. The prevalence of HAV infection increased from 3.5% in the group from 5-14 years of age to 99% in that over the age of 64 years (p < 0.001). A higher prevalence was observed in those born outside of Catalonia (odds ratio [OR] = 3.97; 95% CI, 2.4-6.4) and in those with a lower level of education (OR = 2.60; 95% CI, 1.9-3.5). In the period 1989-1996 the prevalence of the infection has decreased in the population under the age of 45, the differences being statistically significant in the age groups 10-14 (p < 0.0001) and 25-34 (p < 0.0001). CONCLUSIONS: The prevalence of HAV infection has progressively decreased in Catalonia while it proportionally increases the susceptible population under the age of 45 years. These findings may be important in the design of strategies for the prevention of HAV infection with universal vaccination programs against this disease.

Measles immunity and vaccination policy in Catalonia.

The prevalence of antibodies against measles in a representative sample of the school population in Catalonia was established and the results compared with previous studies. The study was carried out in 1996 using blood samples obtained from schoolchildren aged 6-7 years, 10-11 years, 13 14 years and 15-16 years. 1231 schoolchildren were studied. The global prevalence of antibodies was 96.3%, and a considerable increase was observed with respect to the prevalence in 1986 (89.4%). The level of antibodies was 94% at 6-7 years and 10-11 years, 99.7% at 13-14 years and 98.3% at 15 16 years. These data would suggest the advancement of the administration of the second dose of measles-mumps rubella vaccine to 4 6 years instead of at 11 years.

[Low level of immune protection against diphtheria in adult population of Catalonia]. / Bajo grado de protección inmunitaria frente a la difteria en la población adulta de Cataluña.

BACKGROUND: Seroepidemiologic studies carried out in different European countries have shown the existence of low levels of protection against diphtheria. In this study the prevalence of antidiphtheria antibodies in the adult population of Catalonia, Spain, during 1995 has been studied. PATIENTS AND METHODS: The prevalence of the seroprotection against diphtheria was investigated in a representative sample (n = 1,248) of the adult population of Catalonia aged 15 or older. The antibody levels were determined by means of the in vitro Vero-cell neutralization technique. Two protection levels were considered: 0.01-0.09 U/ml (partial immunity) and > or = 0.1 U/ml (total immunity). RESULTS: The prevalence of absolute seroprotection was 12.4% (CI 95%: 10.5-14.3%) and that of partial and absolute seroprotection was 26.0% (CI 95%: 23.6-28.4%). The prevalence of antibodies is higher in men than in women (29.2% versus 23.1%; p < 0.05), and in urban than in rural environments (27.2% versus 19.9%: p < 0.05). The odds ratios adjusted by multiple logistic regression analysis were 1.43 (1.11-1.85) and 1.56 (1.05-2.29), respectively. CONCLUSION: The prevalence of antidiphtheria antibodies in the adult population of Catalonia, Spain, is low. The results suggest the need to develop antidiphtheria vaccination programmes in the adult population.

Importance of sexual transmission of hepatitis C virus in seropositive pregnant women: a case-control study.

The mode of hepatitis C virus (HCV) transmission in patients who deny parenteral exposure is still not understood. Seroprevalence studies of anti-HCV in sexually promiscuous populations and in spouses of infected patients have given contradictory results. We investigated the role of sexual transmission of HCV in a case-control study of risk factors for infection in a series of 43 anti-HCV positive pregnant women and 172 matched controls (4 for each case). In the univariate analysis, the following factors were associated significantly with anti-HCV seropositivity: low social class, unmarried, history of abortion, wounds which were sutured, tattooes, sharing toiletries with the partner, sexual contact outside the partnership without condom use, blood transfusion, and intravenous drug abuse, but only the last 3 factors remained significantly associated with HCV infection in multiple logistic regression analysis. The relative risk of HCV infection increased according to the increased number of sexual partners. Thus sexual transmission must be considered a possible mode of infection in HCV infected persons without parenteral exposures.

Passive smoking and risk of pulmonary tuberculosis in children immediately following infection. A case-control study.

SETTING: Passive smoking-related respiratory disorders in children. OBJECTIVES: To assess the effect of passive smoking on the development of active pulmonary tuberculosis (PTB) in children immediately following infection by Mycobacterium tuberculosis within the family. DESIGN: An unmatched case-control study in which 93 contacts who became cases (active PTB diagnosed) and 95 contacts who did not became cases (tuberculin-positive children without evidence of active disease) were included. All were household contacts of a new case of pulmonary bacillary tuberculosis. Smoking habits were investigated by a questionnaire. Urinary cotinine was analysed. Odds Ratio (OR) was adjusted for age and socio-economic status using multiple logistic regression analysis. RESULTS: Passive smoking was a risk factor for PTB (OR: 5.29; 95% confidence interval (CI): 2.33-12.82; P < 0.00005). The adjusted OR was 5.39 (95% CI: 2.44-11.91; P < 0.00001). The risk increased when contacts were passive smokers both at home and outside the home within the family (OR: 6.35; 95% CI: 3.20, 12.72; P < 0.00001). Contacts 0-4 and 5-9 years old showed a significantly higher risk than those aged > or = 10. There was a dose-response relationship between the risk of developing active PTB immediately following infection and the number of cigarettes smoked daily by the household adults (P < 0.001). Mean (SD) urinary continine detectable concentrations (ng/ml) were different between disease contacts (119.46 [68.61]) and non diseased contacts (91.87 [73.10]). The difference was statistically significant (P < 0.001). CONCLUSIONS: Passive exposure to tobacco smoke in children was associated with an increased risk of developing pulmonary tuberculosis immediately following infection. This is an association of great concern requiring health education programmes and antitobacco medical advice.

Cigarette smoking as a risk factor for tuberculosis in young adults: a case-control study.

SETTING: The association between smoking and pulmonary tuberculosis has not often been studied. OBJECTIVE: To assess the influence of cigarette smoking on the development of active pulmonary tuberculosis in young people who were close contacts of new cases of smear-positive pulmonary tuberculosis. DESIGN: A case-control study in which 46 'cases' (patients with active pulmonary tuberculosis: isolation of Mycobacterium tuberculosis or clinical and/or radiographic evidence of current pulmonary tuberculosis, with a positive tuberculin skin test) and 46 'controls' (persons with positive tuberculin reaction, negative bacteriological test and without clinical and/or radiological evidence of pulmonary tuberculosis) were included. Smoking habits were investigated by questionnaire. Univariate and multivariate analysis was performed, and odds ratio (OR) was adjusted for age, gender and socio-economic status. RESULTS: Statistically significant differences were found in active smokers (occasional and daily smokers) (OR: 3.65; 95% CI, 1.46 and 9.21; P < 0.01), daily smokers (OR: 3.53; 95% CI, 1.34 and 9.26; P < 0.05), and individuals who were both passive and active smokers (OR: 5.10; 95% CI, 1.97 and 13.22; P < 0.01) and passive and daily smokers (OR: 5.59; 95% CI, 2.07 and 15.10; P < 0.001). There was a dose-response relationship between the number of cigarettes smoked daily and the risk of active pulmonary tuberculosis. CONCLUSIONS: The data studied show that cigarette smoking is a risk factor for pulmonary tuberculosis in young people, with a dose-response relationship with the number of cigarettes consumed daily.