Differences in Bordetella pertussis DNA load according to clinical and epidemiological characteristics of patients with whooping cough.

OBJECTIVE: To identify associations between nasopharyngeal Bordetella pertussis DNA load and clinical and epidemiological characteristics and evaluate DNA load prognostic value in pertussis severity. METHODS: Prospective observational multi-centre study including nasopharyngeal samples positive to pertussis DNA by real-time PCR collected from children and adult patients in more than 200 health centres of Catalonia (Spain) during 2012-2013. RESULTS: B. pertussis load was inversely correlated with age (rho = -0.32, p < 0.001), time to diagnosis (rho = -0.33, p < 0.001) and number of symptoms (rho = 0.13, p = 0.002). Median bacterial load was significantly higher in inpatients versus outpatients (4.91 vs. 2.55 log10 CFU/mL, p < 0.001), patients with complications versus those without (6.05 vs. 2.82 log10 CFU/mL, p < 0.001), disease incidence in summer and autumn versus spring and winter (3.50 vs. 2.21 log10 CFU/mL, p = 0.002), and unvaccinated-partially vaccinated patients versus vaccinated (4.20 vs. 2.76 log10 CFU/mL, p = 0.004). A logistic regression model including bacterial load and other candidate prognostic factors showed good prediction for hospital care (AUC = 0.94) although only age and unvaccinated status were found to be prognostic factors. CONCLUSIONS: We observed strong positive associations of nasopharyngeal bacterial load with severity outcomes of hospitalisation and occurrence of complications. Bacterial load and other independent variables contributed to an accurate prognostic model for hospitalisation.

Prevalence of antibody to Bordetella pertussis in neonates and prevalence of recent pertussis infection in pregnant women in Catalonia (Spain) in 2003 and 2013.

BACKGROUND: Infections because of Bordetella pertussis still occur in infants and adults in European countries, despite vaccination coverage against pertussis being high. METHODS: IgG antibody titers to pertussis toxin (anti-PT) were assessed using an enzyme-linked immunosorbent assay test (Serion ELISA classic) in 353 cord blood samples from neonates of a representative sample of pregnant women obtained in Catalonia (Spain) in 2013. Neonates with anti-PT titers ≤ 40 international units (IU)/mL were considered to be unprotected against pertussis. IgG-PT titers >100 IU/mL in umbilical cord samples were considered to be indicative of a current or recent pertussis infection (12 months) in pregnant women. The age-standardized prevalence of recent pertussis infection obtained in this study was compared with the prevalence obtained in 2003. RESULTS: The mean anti-PT titer in neonates was 10.8 IU/mL and 89.8% of neonates were unprotected against pertussis. The prevalence of unprotected neonates as defined by cord blood anti-PT ≤ 40 IU/mL was 90%. The prevalence of recent pertussis infection in pregnant women as defined by cord blood anti-PT >100 IU/mL was 2%. The diphtheria-tetanus-pertussis vaccination coverage during childhood in pregnant women was 75%. The age-standardized prevalence of recent pertussis infection in pregnant women observed in this study (2.2%) was slightly higher than the prevalence obtained in 2003 (1.5%), with an odds ratio = 1.45 (95% confidence intervals: 0.5-3.9), although differences were not statistically significant. CONCLUSIONS: Most neonates are unprotected against pertussis and pertussis infections are frequent in pregnant women in Catalonia. Infants and pregnant women should be the priority population groups for pertussis prevention programs in Catalonia.

Lack of herd immunity against measles in individuals aged <35 years could explain re-emergence of measles in Catalonia (Spain).

OBJECTIVES: The objective of this study was to assess the association between lack of herd immunity in some population groups and the re-emergence of measles in Catalonia in 2006. METHODS: Herd immunity was considered established in the different population groups when the prevalence of positive serological results to measles was higher than the herd immunity threshold of 90%. The Chi-square test and the odds ratio were used to assess the association between lack of herd immunity and measles cases in the outbreak of 2006-2007. RESULTS: Herd immunity was not established against measles in individuals aged 0-14 years and 25-34 years, as the prevalence of positive serological results was <90% in these groups. In the measles outbreak of 2006-2007, 91% of cases occurred in age groups without herd immunity, and only 9% of cases occurred in age groups with herd immunity (p<0.001). The odds ratio for the association between lack of herd immunity and measles cases in the outbreak of 2006-2007 was 104 (p<0.001). CONCLUSION: Lack of herd immunity in individuals aged<35 years could be one of the factors underlying the re-emergence of measles in Catalonia.

Epidemiology and societal costs of gastroesophageal reflux disease and Barrett's syndrome in Germany, Italy and Spain.

AIM: To estimate the economic consequences for society arising from populations with poorly treated gastroesophageal reflux disease (GERD) and Barrett's esophagus in Germany, Italy and Spain. METHODS: The following epidemiologic data were used: total population figures, the prevalence and incidence of GERD and its complications, and data on patients with poorly treated GERD, as well as data on treatment costs and active workers' presenteeism and absenteeism. These data were used to calculate the economic consequences arising from the population with poorly treated GERD and Barrett's esophagus for the healthcare system and employers in each country. RESULTS: The size of the population with poorly treated GERD with Barrett's esophagus was estimated to be 29,678 in Spain, 19,327 in Germany and 10,079 in Italy. Costs for the healthcare systems in Spain, Germany and Italy for the population with poorly treated GERD with Barrett's esophagus were estimated to be €18, 12 and 7 million, respectively, for each country. Total costs for absenteeism and presenteeism for employers due to poorly treated GERD with Barrett's esophagus were €10 million for Germany, €1 million for Italy and none for Spain. CONCLUSION: Costs due to poorly treated GERD with Barrett's esophagus represent a substantial burden for the healthcare systems of all three studied countries. Costs for employers owing to absenteeism or presenteeism of employees were low or no costs were found.

Prevalence of antibodies associated with herd immunity: a new indicator to evaluate the establishment of herd immunity and to decide immunization strategies.

OBJECTIVE: To develop a method to estimate the critical prevalence of antibodies associated with herd immunity (p(c)) and to assess the establishment of herd immunity against measles, mumps, rubella, varicella, and pertussis in Catalonia (Spain) using this method. METHODS: The herd immunity is established when the prevalence of antibodies (positive serological results) is higher than p(c) = I(c) Se/PV, where I(c) is the prevalence of protected individuals necessary to block the transmission of an infection in the population, Se is the sensitivity of the serological test, and PV is the predictive value of a positive serological result. The establishment of herd immunity was assessed comparing the age-group specific p(c) with the prevalence of antibodies (p) observed in Catalonia in 2002 in schoolchildren (6-9 years) and individuals aged 14 to 29 years and 45 to 54 years. RESULTS: The herd immunity was not established (p < p(c)) against measles, mumps, and varicella in schoolchildren aged 6 to 9 years, against measles in individuals aged 15 to 24 years, and against pertussis in all age groups. Based on these results, the measles-mumps-rubella (MMR) vaccine should be given to schoolchildren and individuals aged 15 to 24 years, the varicella vaccine to schoolchildren aged 6 to 9 years, and the diphtheria-tetanus-pertussis (DTaP/dTaP) vaccine to all age groups in order to establish the necessary herd immunity in the population. CONCLUSION: Serological surveys and the critical prevalence of antibodies can be used to assess the establishment of herd immunity for vaccine-preventable diseases in different population groups, indicating to which of them immunization activities should be prioritized.

Prevalence of protective measles virus antibody levels in umbilical cord blood samples in Catalonia, Spain.

The prevalence of protective antibody levels (>160 mIU/ml) in neonates was 98.5%. The mean measles virus antibody level was 3,406 mIU/ml and increased with maternal age. Measles vaccination was reported by 42% of pregnant women and decreased with age.

Prevalence of pertussis antibodies in umbilical cord blood samples in Catalonia, Spain.

The objective of the study was to determine the prevalence of detectable antipertussis antibodies (anti-PT) and recent pertussis infection in a representative sample (n=508) of pregnant women in Catalonia (Spain). Antipertussis (PT) antibodies were determined in cord blood samples using an in-house enzyme-linked immunosorbent assay test. The prevalence of detectable anti-PT levels was 72.8% and the prevalence of recent pertussis infection in mothers (cord blood anti-PT level of > or = 195 EU/mL was 1.8%. The (P<0.05) and the prevalence of recent pertussis infection decreased with maternal age (P< 0.01). Results obtained in this study show that it might be necessary to develop a pertussis vaccination program using acellular pertussis vaccines aimed at pregnant women to reduce the risk of pertussis infection during pregnancy and in neonates.

Recommendations for the prevention and treatment of influenza using antiviral drugs based on cost-effectiveness.

Influenza is an acute respiratory disease that causes epidemics and pandemics in the human population of temperate regions. Influenza epidemics occur every year during the winter months, affecting approximately 10% of the population. The primary strategy for reducing the effect of influenza in the community is to vaccinate persons who are at risk or caring for high-risk individuals each year before seasonal increases in influenza virus circulation occur. Antiviral drugs can be used for the treatment of influenza and the prevention of seasonal and post-exposure influenza. Four antiviral drugs are available for the prevention and treatment of influenza infections: oseltamivir, zanamivir, rimantadine and amantadine. Antiviral drugs can be used for the treatment of influenza and for post-exposure and seasonal influenza prevention. The cost-effectiveness of antiviral therapies ranged from cost savings to more than US$130,000 per quality-adjusted life-year (QALY) for influenza treatment, from GB pound9000 to more than pound1 million per QALY for seasonal prevention and from cost savings to pound100,000 per QALY for post-exposure prevention. Based on the cost-effectiveness threshold of pound30,000 or $40,000 per QALY, antiviral therapies can be recommended for influenza treatment and post-exposure prevention in healthy and high-risk individuals and for seasonal prevention in high-risk individuals. Zanamivir, oseltamivir and amantadine have favorable cost-effectiveness ratios for these interventions, but amantadine should only be used in countries with a low prevalence of resistant virus. The stockpile of antiviral drugs should be maintained in developed countries because they are cost effective for the prevention and treatment of a possible influenza pandemic.

Evaluación de los programas de vacunación mediante estudios serológicos y vacunas distribuidas / Evaluation of vaccination programs through serological studies and distributed vaccines

Antecedentes: El objetivo del estudio fue comparar las coberturas vacunales en escolares para la vacuna triple vírica (sarampión-rubéola-parotiditis), DTP (difteria-tétanos-tos ferina) y poliomielitis, obtenidas a partir de las vacunas distribuidas a los centros de vacunación, las vacunaciones declaradas y el análisis serológico de anticuerpos. Métodos: La cobertura vacunal se obtuvo a partir de los antecedentes de vacunación recogidos en un cuestionario y mediante el análisis serológico de anticuerpos frente al sarampión para la vacuna triple vírica, y el tétanos para la vacuna DTP en una muestra representativa de escolares en 2001. La cobertura vacunal por registros se obtuvo dividiendo el número de individuos que podían haber completado la vacunación por la población objetivo. Se evaluó la concordancia entre los antecedentes de vacunación y los resultados serológicos mediante el índice kappa. Resultados: En los escolares de 6-8 y 9-11 años de edad se obtuvo una cobertura vacunal por cuestionario del 85,5 y el 87,6% para la vacuna DTP, del 89,9 y el 89,6% para la vacuna triple vírica, y del 90,4 y el 89,4% para la vacuna poliomielítica, respectivamente, mientras la cobertura vacunal por análisis serológico fue del 100 y el 99,6% para la vacuna DTP, y del 85,5 y el 93,3% para la vacuna triple vírica, respectivamente. La cobertura vacunal por registros fue significativamente mayor que la obtenida mediante estos 2 métodos: un 93,5 y un 100% para la vacuna DTP, un 96,3 y un 98,8% para la vacuna triple vírica, y un 100% para la vacuna poliomielítica. La concordancia obtenida entre los antecedentes de vacunación y los resultados serológicos fue muy baja (κ < 0,2). Conclusión: La planificación y la evaluación de los programas vacunales se debería basar en las coberturas obtenidas mediante análisis serológico en muestras representativas de la población escolar

Background: The objective of this study was to compare vaccination coverage in schoolchildren for the measles-mumps-rubella (MMR) and diphtheria-tetanus-pertussis (DTP) triple vaccines, and the poliomyelitis vaccine based on: a) vaccines distributed to vaccination centers; b) reported vaccination history, and c) serological analysis of antibodies. Methods: Vaccination coverage was calculated on the basis of vaccination history collected by questionnaire, and by serological analysis of antibodies against measles for the MMR vaccine and against tetanus for the DTP vaccine in a representative sample of schoolchildren in 2001. The vaccination coverage from vaccination registries was obtained by dividing the number of individuals who could have completed their vaccinations by the target population. The concordance between the vaccination history and serological analysis was evaluated using the kappa test. Results: The vaccination coverage obtained by questionnaire in schoolchildren aged 6-8 and 9-11 years was 85.5 and 87.6% for the DTP vaccine, 89.9 and 89.6% for the MMR vaccine, and 90.4 and 89.4% for the poliomyelitis vaccine, respectively, while the vaccination coverage obtained by serological analysis was 100 and 99.6% for the DTP vaccine and 85.5 and 93.3% for the MMR vaccine, respectively. The vaccination coverages obtained from distributed vaccines were significantly higher: 93.5 and 100% for the DTP vaccine, 96.3 and 98.8% for the MMR vaccine and 100% for the poliomyelitis vaccine. A low concordance was obtained between the vaccination history and serological analysis of antibodies (κ < 0.2). Conclusion: Planning and evaluation of vaccination programs should be based on vaccination coverages obtained from serological analysis of antibodies in representative samples of schoolchildren

[Evaluation of vaccination programs through serological studies and distributed vaccines]. / Evaluación de los programas de vacunación mediante estudios serológicos y vacunas distribuidas.

BACKGROUND: The objective of this study was to compare vaccination coverage in schoolchildren for the measles-mumps-rubella (MMR) and diphtheria-tetanus-pertussis (DTP) triple vaccines, and the poliomyelitis vaccine based on: a) vaccines distributed to vaccination centers; b) reported vaccination history, and c) serological analysis of antibodies. METHODS: Vaccination coverage was calculated on the basis of vaccination history collected by questionnaire, and by serological analysis of antibodies against measles for the MMR vaccine and against tetanus for the DTP vaccine in a representative sample of schoolchildren in 2001. The vaccination coverage from vaccination registries was obtained by dividing the number of individuals who could have completed their vaccinations by the target population. The concordance between the vaccination history and serological analysis was evaluated using the kappa test. RESULTS: The vaccination coverage obtained by questionnaire in schoolchildren aged 6-8 and 9-11 years was 85.5 and 87.6% for the DTP vaccine, 89.9 and 89.6% for the MMR vaccine, and 90.4 and 89.4% for the poliomyelitis vaccine, respectively, while the vaccination coverage obtained by serological analysis was 100 and 99.6% for the DTP vaccine and 85.5 and 93.3% for the MMR vaccine, respectively. The vaccination coverages obtained from distributed vaccines were significantly higher: 93.5 and 100% for the DTP vaccine, 96.3 and 98.8% for the MMR vaccine and 100% for the poliomyelitis vaccine. A low concordance was obtained between the vaccination history and serological analysis of antibodies (kappa < 0.2). CONCLUSION: Planning and evaluation of vaccination programs should be based on vaccination coverages obtained from serological analysis of antibodies in representative samples of schoolchildren.