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1.
Hum Vaccin ; 6(2): 212-8, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19946212

RESUMEN

Little is known about the impact of low-dose hepatitis B vaccine on the persistence of anti-HBs and immune memory in school-age children. Recombivax-HB 2.5 µg (RB) has been widely used in school-age children. RB induces high seroprotectionrates, but relatively low anti-HBs titers. The main objectives of this phase of the study were to assess anti-HBs persistence and the presence of immune memory 10 years post-vaccination of 8-10 year-old children with 3 doses of RB and the persistence of anti-HBs post-booster dose administration 5 (Group A; n=250) or 10 years (Group B; n=263) post-vaccination. No significant difference was observed between GMTs and the proportion of subjects with anti-HBs titers ≥ 10 mIU/mL 5 or 10 years post-vaccination. In both groups, a 56-fold decrease of anti-HBs GMTs was observed. One month post-booster, all but two subjects in Group A had an anti-HBs titer ≥ 10 mIU/mL. A 4.9- and 11.4-fold decrease in anti-HBs GMTs were observed during the first year post-booster in Group A and B, respectively. One year post-booster, the two groups were equivalent: ≥ 98.8% of subjects had an anti-HBs ≥ 10 mIU/mL. In group A, five years post-booster, 96.8% had a titer ≥ 10 mIU/mL; the GMT was 17-fold higher than the GMT 5 years post-vaccination (p<0.0001). In both groups, there was a strong positive correlation (p<0.0001) between anti-HBs titers observed post-primary vaccination and at following study time points (r=0.70-0.90). Three doses of RB administered at the age of 8-10 years induce a 10 years long-lasting immunity in virtually all vaccinees. The booster does not appear necessary on a 10 years perspective.


Asunto(s)
Anticuerpos contra la Hepatitis B/sangre , Vacunas contra Hepatitis B/inmunología , Memoria Inmunológica , Adolescente , Niño , Femenino , Hepatitis B/inmunología , Hepatitis B/prevención & control , Anticuerpos contra la Hepatitis B/inmunología , Vacunas contra Hepatitis B/administración & dosificación , Humanos , Esquemas de Inmunización , Inmunización Secundaria , Masculino , Factores de Tiempo , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/inmunología , Adulto Joven
2.
Clin Infect Dis ; 48(11): 1493-9, 2009 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-19400689

RESUMEN

BACKGROUND: We assessed the scientific basis and practical implications of recommendations made since the late 1990s to offer rabies postexposure prophylaxis (RPEP) for occult bat encounters, including recommendations to offer RPEP to persons with bedroom exposure to a bat while sleeping without evidence of direct physical contact. METHODS: The number needed to treat after bedroom exposure to a bat was calculated as the percentage of population exposed multiplied by the inverse of crude rabies incidence. Bedroom exposure was estimated in a population survey of 14,453 households. Incidence was based on reported human cases in Canada and the United States, 1990-2007. RESULTS: In the population surveyed, bedroom bat exposure while sleeping and without known physical contact occurred at an annual rate of 0.099%. We estimate that <5% of eligible persons with bedroom exposure receive RPEP as recommended. The incidence of human rabies due to bedroom bat exposure without recognized contact was 1 case per 2.7 billion person-years. The number needed to treat to prevent a single case of human rabies in that context ranges from 314,000 to 2.7 million persons. A total of 293-2500 health care professionals working full-time for a full year would be required to prevent a single human case of bat rabies due to bedroom exposure without recognized contact. Amounts of Can $228 million to Can $2.0 billion are additionally required for associated material costs. CONCLUSIONS: Human rabies acquired through bedroom exposure to a bat while sleeping and without recognized contact is rare. Conversely, such exposures are not uncommon in the population, and the resources required for associated RPEP are orders of magnitude higher than those required for most interventions that are considered to be reasonable. Current RPEP recommendations related to occult bat contact should be reconsidered.


Asunto(s)
Quirópteros , Rabia/epidemiología , Rabia/prevención & control , Zoonosis/transmisión , Animales , Canadá/epidemiología , Humanos , Incidencia , Rabia/economía , Rabia/transmisión , Estados Unidos/epidemiología
3.
J Adv Nurs ; 65(3): 499-508, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19222647

RESUMEN

AIM: This paper is a report of a survey: (1) to document nurses' knowledge, attitudes and information needs regarding human papillomavirus prevention and (2) to determine factors associated with their willingness to recommend human papillomavirus vaccines. BACKGROUND: Persistent infection with human papillomavirus has been causally linked to cervical cancer. Two human papillomavirus vaccines have recently been approved for use in more than 65 countries. Nurses' level of support for the prevention of human papillomavirus related diseases by vaccination has not been researched. METHODS: A survey was conducted in 2007. Self-administered questionnaires were mailed to 1799 randomly selected nurses. Descriptive statistics were generated for all variables. Multivariable logistic regression models were estimated to determine variables associated with the willingness to recommend human papillomavirus vaccines. RESULTS: A total of 946 questionnaires were analyzed and showed that: 97% of nurses perceived routinely recommended vaccines as very useful; 93% would support human papillomavirus vaccination if it is publicly funded; 85% would recommend human papillomavirus vaccines to their patients; 33%, 46% and 61% expect the vaccination to permit screening to begin later in life, reduction of the frequency of screening, and reduction of the number of postscreening interventions, respectively. Respondents' knowledge score was 3.8 out of 7. Several modifiable factors, including knowledge, perceived self-efficacy, and societal and colleagues support were associated with willingness to recommend vaccines. CONCLUSION: Most nurses' support human papillomavirus vaccination, but their active involvement should not be taken for granted. Targeted educational efforts are needed to ensure nurses' involvement in the prevention of human papillomavirus-related diseases.


Asunto(s)
Enfermeras y Enfermeros/psicología , Infecciones por Papillomavirus/prevención & control , Vacunas contra Papillomavirus/administración & dosificación , Displasia del Cuello del Útero/prevención & control , Vacunación/psicología , Adolescente , Adulto , Canadá , Niño , Detección Precoz del Cáncer , Educación Continua en Enfermería , Femenino , Conocimientos, Actitudes y Práctica en Salud , Humanos , Encuestas y Cuestionarios , Adulto Joven
4.
Pharmacoeconomics ; 26(1): 17-32, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18088156

RESUMEN

Hepatitis A vaccines have been available for more than a decade. Because the burden of hepatitis A virus has fallen in developed countries, the appropriate role of vaccination programmes, especially universal vaccination strategies, remains unclear. Cost-effectiveness analysis is a useful method of relating the costs of vaccination to its benefits, and may inform policy. This article systematically reviews the evidence on the cost effectiveness of hepatitis A vaccination in varying populations, and explores the effects of methodological quality and key modelling issues on the cost-effectiveness ratios.Cost-effectiveness/cost-utility studies of hepatitis A vaccine were identified via a series of literature searches (MEDLINE, EMBASE, HSTAR and SSCI). Citations and full-text articles were reviewed independently by two reviewers. Reference searching, author searches and expert consultation ensured literature saturation. Incremental cost-effectiveness ratios (ICERs) were abstracted for base-case analyses, converted to $US, year 2005 values, and categorised to reflect various levels of cost effectiveness. Quality of reporting, methodological issues and key modelling issues were assessed using frameworks published in the literature.Thirty-one cost-effectiveness studies (including 12 cost-utility analyses) were included from full-text article review (n = 58) and citation screening (n = 570). These studies evaluated universal mass vaccination (n = 14), targeted vaccination (n = 17) and vaccination of susceptibles (i.e. individuals initially screened for antibody and, if susceptible, vaccinated) [n = 13]. For universal vaccination, 50% of the ICERs were <$US20 000 per QALY or life-year gained. Analyses evaluating vaccination in children, particularly in high incidence areas, produced the most attractive ICERs. For targeted vaccination, cost effectiveness was highly dependent on the risk of infection.Incidence, vaccine cost and discount rate were the most influential parameters in sensitivity analyses. Overall, analyses that evaluated the combined hepatitis A/hepatitis B vaccine, adjusted incidence for under-reporting, included societal costs and that came from studies of higher methodological quality tended to have more attractive cost-effectiveness ratios. Methodological quality varied across studies. Major methodological flaws included inappropriate model type, comparator, incidence estimate and inclusion/exclusion of costs.


Asunto(s)
Vacunas contra la Hepatitis A/economía , Vacunas contra la Hepatitis A/uso terapéutico , Hepatitis A/prevención & control , Vacunación Masiva/economía , Canadá , Análisis Costo-Beneficio , Anticuerpos Antihepatitis/análisis , Hepatovirus/inmunología , Humanos , Años de Vida Ajustados por Calidad de Vida , Factores de Riesgo , Sensibilidad y Especificidad , Evaluación de la Tecnología Biomédica
5.
BMC Infect Dis ; 7: 31, 2007 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-17442107

RESUMEN

BACKGROUND: In Canada, targeted vaccination of at risk groups for hepatitis A (HA) is done since the mid 1990s resulting in declining incidence. This study estimated the year and age specific hospitalization rates and distribution of risk factors for HA in Quebec, Canada, between 1990 and 2003. METHODS: Records of patients hospitalized with HA-related diagnostic codes were retrieved from the provincial database. Hospital charts of all deceased cases and a random sample of all other records were reviewed. RESULTS: From 1503 hospitalization records, 573 charts were reviewed including 49 (91%) of the 54 deceased patients. Confirmed acute HA was present in 79% of records where HA was the primary diagnosis, and in 3%-8% of records where HA was a secondary diagnosis. From the total estimated number of hospitalizations, 96% had HA as the primary diagnosis. The hospitalization rate decreased from 1.06 per 100 000 person-years between 1990 and 1997 to 0.36 between 1998 and 2003. During the study period, 54% HA hospitalizations were in 20-39 year-olds. The overall case fatality ratio among hospitalized patients was 1.4%, increasing from 0.4% in those < 40 years old to 12.5% in those > or =60 years. By decreasing order, reported risk factors were travel to HA endemic countries (30%), MSM (18%) and household contacts (11%). CONCLUSION: HA hospitalization rates have been low since 1998 but the cause of this is unclear given the cyclical pattern of HA. Travel to endemic countries remains the most important risk factor and improved control of HA will require better strategies to vaccinate travelers.


Asunto(s)
Hepatitis A/epidemiología , Adulto , Femenino , Hepatitis A/mortalidad , Hepatitis A/transmisión , Hospitalización/tendencias , Humanos , Masculino , Persona de Mediana Edad , Quebec/epidemiología , Factores de Riesgo
6.
BMC Public Health ; 7: 304, 2007 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-17961209

RESUMEN

BACKGROUND: The Pap test has been used for cervical cancer screening for more than four decades. A human papillomavirus (HPV) vaccine has been approved for use in Canada and is commercially available now. These two preventive interventions should be considered simultaneously. General population support is an important factor for the successful combination of these interventions. The study had two objectives: 1) To assess practices, beliefs, and attitudes regarding Pap test screening and HPV immunization; 2) To identify socio-demographic factors for Pap screening and vaccine acceptability. METHODS: In 2006, 500 adults were invited to participate in a telephone survey in the region of Quebec City (urban and rural population, 600 000), Canada. Some neutral and standardized information on Pap test and HPV was provided before soliciting opinions. RESULTS: 471 adults (18-69 year-olds) answered the questionnaire, the mean age was 45 years, 67% were female, and 65% had college or university degree. Eighty-six percent of women had undergone at least one Pap-test in their life, 55% in the last year, and 15% from 1 to 3 years ago. Among screened women, the test had been performed in the last three years in 100% of 18-30 year-olds, but only in 67% of 60-69 year-olds (P < 0.0001). Only 15% of respondents had heard of HPV. Eighty-seven percent agreed that HPV vaccines could prevent cervical cancer, 73% that the vaccine has to be administered before the onset of sexual activity, 89% would recommend vaccination to their daughters and nieces. Among respondents < 25 years, 91% would agree to receive the vaccine if it is publicly funded, but only 72% would agree to pay $100/dose. CONCLUSION: There is an important heterogeneity in cervical cancer screening frequency and coverage. Despite low awareness of HPV infection, the majority of respondents would recommend or are ready to receive the HPV vaccine, but the cost could prevent its acceptability.


Asunto(s)
Actitud Frente a la Salud , Infecciones por Papillomavirus/prevención & control , Vacunas contra Papillomavirus/uso terapéutico , Neoplasias del Cuello Uterino/prevención & control , Adulto , Anciano , Coito , Femenino , Encuestas de Atención de la Salud , Humanos , Masculino , Persona de Mediana Edad , Infecciones por Papillomavirus/psicología , Relaciones Padres-Hijo , Quebec , Encuestas y Cuestionarios , Teléfono , Neoplasias del Cuello Uterino/psicología , Frotis Vaginal/estadística & datos numéricos
7.
Can J Infect Dis Med Microbiol ; 18(3): 205-8, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-18923723

RESUMEN

Globally, the pharmaceutical industry is condensing into fewer, larger international corporations. This has occurred with the vaccine industry in Canada, where two domestic producers have been absorbed by international companies. This changes the relationship between Canadian vaccine researchers and corporate head office research directors, who carefully assign prelicensure studies to potential market countries around the globe. To succeed in attracting prelicensure vaccine studies, Canadian researchers need to be outstanding in quality, reliability and efficiency. The present article highlights strategies to help researchers remain internationally competitive for industry-sponsored pharmaceutical studies.

8.
Pediatr Infect Dis J ; 25(4): 372-4, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16567995

RESUMEN

Ten years after a school-based hepatitis B immunization program was implemented, we conducted a study to assess the impact of the program, vaccine failures, risk factors and the number of cases potentially preventable by the addition of an infant vaccination program. The preteen vaccination program is highly effective. An infant immunization program would bring additional benefits.


Asunto(s)
Vacunas contra Hepatitis B/administración & dosificación , Hepatitis B/epidemiología , Hepatitis B/prevención & control , Programas de Inmunización , Evaluación de Programas y Proyectos de Salud , Adolescente , Adulto , Niño , Preescolar , Femenino , Virus de la Hepatitis B/inmunología , Humanos , Esquemas de Inmunización , Incidencia , Lactante , Masculino , Quebec/epidemiología , Resultado del Tratamiento
9.
Pediatr Infect Dis J ; 25(12): 1184-6, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17133168

RESUMEN

We compared the trip characteristics of 84 child and 99 adult cases with travel-acquired hepatitis A (HA). Most pediatric cases had traveled in Asia for more than 30 days and had stayed and eaten most of their meals in the homes of friends and relatives in a country where they had not been born. In contrast, the adults with travel-acquired HA had visited Latin America or the Caribbean for 14 days or less and had stayed primarily in hotels. Specific public health interventions should be undertaken to prevent HA in traveling children.


Asunto(s)
Hepatitis A/epidemiología , Viaje , Adolescente , Adulto , Anciano , Niño , Preescolar , Humanos , Persona de Mediana Edad , Factores de Riesgo
10.
BMC Infect Dis ; 6: 174, 2006 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-17147828

RESUMEN

BACKGROUND: Infection rates for many infectious diseases have declined over the past century. This has created a cohort effect, whereby older individuals experienced a higher infection rate in their past than younger individuals do now. As a result, age-stratified seroprevalence profiles often differ from what would be expected from constant infection rates. METHODS: Here, we account for the cohort effect by fitting an age-structured compartmental model with declining transmission rates to Hepatitis A seroprevalence data for Canadian-born individuals. We compare the predicted impact of universal vaccination with and without including the cohort effect in the dynamic model. RESULTS: We find that Hepatitis A transmissibility has declined by a factor of 2.8 since the early twentieth century. When the cohort effect is not included in the model, incidence and mortality both with and without vaccination are significantly over-predicted. Incidence (respectively mortality) over a 20 year period of universal vaccination is 34% (respectively 90%) higher than if the cohort effect is included. The percentage reduction in incidence and mortality due to vaccination are also over-predicted when the cohort effect is not included. Similar effects are likely for many other infectious diseases where infection rates have declined significantly over past decades and where immunity is lifelong. CONCLUSION: Failure to account for cohort effects has implications for interpreting seroprevalence data and predicting the impact of vaccination programmes with dynamic models. Cohort effects should be included in dynamic modelling studies whenever applicable.


Asunto(s)
Vacunas contra la Hepatitis A , Hepatitis A/epidemiología , Hepatitis A/prevención & control , Programas de Inmunización , Modelos Biológicos , Adolescente , Adulto , Factores de Edad , Canadá/epidemiología , Niño , Preescolar , Efecto de Cohortes , Estudios de Cohortes , Hepatitis A/transmisión , Humanos , Incidencia , Lactante , Persona de Mediana Edad , Estudios Seroepidemiológicos , Viaje
11.
BMC Health Serv Res ; 6: 157, 2006 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-17156461

RESUMEN

BACKGROUND: In countries with low hepatitis A (HA) endemicity, infected food handlers are the source of most reported foodborne outbreaks. In Canada, accessible data repositories of infected food handler incidents are not available. We undertook a systematic review of such incidents to evaluate the extent of viral transmission through food contamination and the scope of post-exposure prophylaxis (PEP) interventions. METHODS: A systematic search of MEDLINE and EMBASE was conducted to identify published reports of incidents in Canada. An expanded search of a news repository (i.e., transcripts from newspapers and newscasts) was also conducted to identify the location and timing of an incident, which was used to retrieve the related report by contacting local public health departments. Data pertaining to case identification, public health risk, PEP interventions, and associated costs was independently abstracted by two reviewers and summarized according to incidents with and without large PEP interventions. RESULTS: A total of 16 incidents were identified from 1998-2004. There were approximately 3 incidents requiring public notification per year. Only 12.5% of incidents were described in published reports, indicating that published data significantly underestimated the number of incidents and PEP interventions. Data pertaining to the remaining incidents was unpublished, sparse and highly dispersed at the local public health level. Six of the 16 incidents required large PEP interventions to immunize on average 5000 potentially exposed individuals. Secondary transmission was low. Characteristics of incidents requiring large PEP interventions included potentially infectious food handlers working with uncooked food for a prolonged duration in high-volume grocery stores in high-density urban areas. CONCLUSION: Infected food handlers with hepatitis A virus (HAV) requiring public notification are not infrequent in Canada. Published data severely underestimated the burden of PEP intervention. Better and consistent reporting at the local and national level as well as a national data repository should be considered for the management of future incidents.


Asunto(s)
Contaminación de Alimentos/estadística & datos numéricos , Manipulación de Alimentos , Hepatitis A/epidemiología , Salud Pública/métodos , Canadá/epidemiología , Notificación de Enfermedades , Brotes de Enfermedades , Contaminación de Alimentos/análisis , Hepatitis A/etiología , Humanos , Incidencia
12.
Clin Infect Dis ; 40(8): 1116-22, 2005 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-15791510

RESUMEN

BACKGROUND: After a mass-immunization campaign in the province of Quebec, Canada, from 1992 to 1993, a case-control study was conducted to evaluate the effectiveness of the polysaccharide vaccine, while controlling for the potential confounding effects of selected risk factors for serogroup C meningococcal disease. METHODS: The case patient group comprised 74 individuals with confirmed serogroup C meningococcal disease reported after the beginning of the campaign until 31 March 1998. Four control subjects, matched for age and place of residence, were randomly selected from the Quebec health insurance registry. Information on case patients was obtained from regional public health departments. Case patients and control subjects (or a family member) were interviewed by telephone. The analyses were conducted by using conditional logistic regression models. RESULTS: Although the 95% confidence intervals (CIs) were large as a result of the small sample sizes, a high level of protection was found among children aged >or=6 years, during the first 2 years after vaccination (vaccine effectiveness, 95%; 95% CI, 68%-99%; P<.002), and protection remained high during the following 3 years (77%; 95% CI, -364% to 99%; P=.34). For children aged 2-5 years, the estimated effectiveness was positive during the first 2 years (62%; 95% CI, -403% to 97%; P=.47) but was negative during the following period (-74%; 95% CI, -1956% to 85%; P=.66). Among children aged <2 years, there was no evidence of protection. Household crowding and disadvantaged socioeconomic conditions were associated with increased risk of disease. CONCLUSIONS: The polysaccharide vaccine remains a cost-effective option for the short-term protection of school-aged children and adults; however, conjugate vaccines are needed for younger children.


Asunto(s)
Infecciones Meningocócicas/prevención & control , Vacunas Meningococicas/inmunología , Polisacáridos Bacterianos/inmunología , Adulto , Envejecimiento , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Humanos , Programas de Inmunización , Lactante , Masculino , Infecciones Meningocócicas/inmunología , Oportunidad Relativa , Quebec/epidemiología , Factores de Riesgo , Factores Socioeconómicos
13.
Pediatr Infect Dis J ; 24(6): 514-9, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15933561

RESUMEN

BACKGROUND: Hepatitis A vaccines provide consistent, long-lasting protection and have been available for almost 10 years in Canada, but their use remains limited. It is difficult to assess their optimal utilization given that our knowledge of hepatitis A epidemiology in Canada is fragmentary. Unlike the United States, no nationwide study of hepatitis A prevalence has ever been done in Canada. Consequently we do not know the incidence of infection in children and what would be the most appropriate age for hepatitis A vaccination. OBJECTIVE: To estimate the proportion of 8- to 13-year-old children who have been infected with hepatitis A virus (HAV) and the risk factors for this infection on a nationwide scale. METHODS: Children were sampled in 10 Canadian provinces, comprising 5 regions, using random digit dialing methodology with regional stratification. Demographic data and information about risk factors for hepatitis A were collected by the telephone interviewers. Oral fluid samples were self-collected and mailed to the laboratory, where they were tested for anti-HAV IgG. RESULTS: Of 6740 contacted families with a child of required age, 1688 (25%) agreed to participate and answered the questionnaire. From these, 1074 oral fluid samples were received, and 1057 could be analyzed. Anti-HAV IgG was detected in 2.7% of subjects, with variation by region from 0.8 to 3.4%. The parents of 54 subjects (5.1%) reported that their child had previously been vaccinated against HAV. Anti-HAV IgG was present in 2.0% of unvaccinated subjects, among whom antibody prevalence was 19.4% in children born in HAV-endemic countries, 6.1% in Native children and 4.2% in travelers to endemic countries. In multivariate analysis of all subjects, the presence of anti-HAV IgG was significantly associated with birth in an endemic country, travel to an endemic country, Native status (American Indian and Inuit population), female gender and vaccination against HAV. In nonvaccinated, non-Native children born in Canada who did not travel to endemic countries, anti-HAV prevalence was 1.1%. CONCLUSIONS: The risk for hepatitis A during childhood is low in Canada. Almost all teenagers (>97%) would be at risk for infection in case of contact with HAV. Changes in immunization policy against hepatitis A should be considered.


Asunto(s)
Anticuerpos de Hepatitis A/sangre , Virus de la Hepatitis A Humana/inmunología , Hepatitis A/epidemiología , Adolescente , Canadá/epidemiología , Niño , Femenino , Humanos , Masculino , Prevalencia , Factores de Riesgo
14.
Pediatr Infect Dis J ; 24(3): 213-8, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15750456

RESUMEN

BACKGROUND: Few data are available concerning the long term immunogenicity of the pediatric doses of hepatitis B vaccines given to preteenagers. The long term effect of the booster dose in teenagers is unknown. We evaluated the immunogenicity of 2 pediatric hepatitis vaccines after primary vaccination and after a booster dose. METHODS: A prospective 15-year follow-up study of the immunogenicity of 2 hepatitis B vaccines was initiated in 1995 in Quebec City, Canada. One year apart, 1129 children 8-10 years old received Engerix-B 10 microg (EB), and 1126 received Recombivax-HB 2.5 microg (RB) vaccine after a 0-, 1-, 6-month schedule. After 5 years, one-third of the 2 cohorts were randomly selected. A booster dose of EB 10 microg or RB 5 microg was administered according to the vaccine used in the primary immunization. Antibodies were measured before, 1 month after and 1 year after the booster injection. RESULTS: Before the booster dose, anti-HB surface antibody (HBs) was detected in 94.7% of the EB subjects and in 95.2% of the RB subjects (P = 0.85). The geometric mean titer (GMT) was higher in the EB than in the RB group (252 mIU/mL versus 66 mIU/mL, P < 0.0001). One month after the booster, 99.7% of subjects in the EB group and 99.6% in the RB group had a detectable anti-HBs, and 99.0 and 99.3%, respectively, had anti-HBs > or =10 mIU/mL. The anti-HBs GMT was 113,201 mIU/mL in the EB and 16,623 mIU/mL in the RB groups (P < 0.0001). One year after the booster, 99.3% of subjects in the EB group and 100% in the RB group had detectable anti-HBs, and 97.9 and 98.5% respectively, had anti-HBs > or =10 mIU/mL. The anti-HBs GMT was 14,028 mIU/mL in the EB and 3437 mIU/mL in the RB group (P < 0.0001). CONCLUSIONS: The immunity persists for at least 5 years after the primary vaccination with both pediatric vaccines in 99% of children vaccinated at the age of 8-10 years. It confirms that no booster is needed at that point.


Asunto(s)
Anticuerpos contra la Hepatitis B/inmunología , Vacunas contra Hepatitis B/administración & dosificación , Hepatitis B/inmunología , Hepatitis B/prevención & control , Inmunidad/fisiología , Inmunización Secundaria , Vacunas Sintéticas/administración & dosificación , Análisis de Varianza , Niño , Estudios de Cohortes , Enfermedades Endémicas , Femenino , Estudios de Seguimiento , Hepatitis B/epidemiología , Anticuerpos contra la Hepatitis B/análisis , Humanos , Esquemas de Inmunización , Memoria Inmunológica , Incidencia , Masculino , Análisis Multivariante , Estudios Prospectivos , Quebec/epidemiología , Medición de Riesgo , Factores de Tiempo , Vacunación/normas , Vacunación/tendencias
15.
BMC Infect Dis ; 5: 56, 2005 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-16001978

RESUMEN

BACKGROUND: In Canada--a low endemicity country, vaccines for hepatitis A virus (HAV) are currently recommended to individuals at increased risk for infection or its complications. Applying these recommendations is difficult because the epidemiology of HAV infection is poorly defined, complex, and changing. This systematic review aimed to 1) estimate age-specific prevalence of HAV antibody in Canada and 2) evaluate infection-associated risk factors. METHODS: MEDLINE (1966-2005) and EMBASE (1980-2005) were searched to identify relevant studies for the systematic review. Archives for the Canada Diseases Weekly Report (1975-1991) and Canada Communicable Disease Report (1992-2005) were searched for relevant public health reports. Data were abstracted for study and participants' characteristics, age-specific prevalence, and risk factors. RESULTS: A total of 36 reports describing 34 unique studies were included.The seroprevalence in Canadian-born children was approximately 1% in ages 8-13, 1-6% in 20-24, 10% in 25-29, 17% in 30-39, and increased subsequently. In age groups below 20 and 20-29, age-specific seroprevalence generally remained constant for studies conducted across geographic areas and over time. Compared to Canadian-born individuals, subjects born outside Canada were approximately 6 times more likely to be seropositive (relative risk: 5.7 [95% CI 3.6, 9.0]). Travel to high risk areas in individuals aged 20-39 was associated with a significant increase in anti-HAV seropositivity (RR 2.8 [1.4, 5.5]). Compared to heterosexuals, men having sex with men were only at a marginally higher risk (adjusted odds ratio 2.4 [0.9, 6.1]). High risk for seropositivity was also observed for Canadian First Nations and Inuit populations. CONCLUSION: Results from the current systematic review show that in this low endemicity country, disease acquisition occurs in adulthood rather than childhood. The burden of disease is high; approximately 1 in 10 Canadians had been infected by ages 24-29. The increase in prevalence in young adults coincides with disease importation and increasing frequency of risk factors, most likely behavioral-related ones. Gaps in seroprevalence data were identified rendering the application of current immunization recommendations difficult. A nationwide prevalence survey for all Canadians is needed. This is essential to quantify the effectiveness of current recommendations and conduct cost-effectiveness evaluations of alternative immunization programs, if necessary.


Asunto(s)
Hepatitis A/epidemiología , Factores de Edad , Canadá/epidemiología , Humanos , Factores de Riesgo , Estudios Seroepidemiológicos
16.
Arch Intern Med ; 164(20): 2266-72, 2004 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-15534165

RESUMEN

BACKGROUND: Oculorespiratory syndrome (ORS) after influenza vaccination has many features of an allergic reaction. METHODS: The objective of the study was to estimate the recurrence rate of ORS after receipt of either of 2 influenza vaccines available in Canada for the 2002-2003 influenza season in individuals who experienced ORS in 2000 or 2001. We designed a randomized, crossover, double-blind, placebo-controlled trial in which patients received the vaccine and the placebo 7 days apart. Patients were contacted by telephone at 24 hours and seen at 7 days to collect information about the recurrence of ORS symptoms. The 146 patients belonged to 3 groups: group A (46 patients) had ORS in 2000 but were not revaccinated in 2001, group B (50 patients) had ORS in 2000 and were revaccinated in 2001, and group C (50 patients) had ORS in 2001 but not in 2000. Half of the participants received Fluviral S/F (Shire Biologics) and half received Vaxigrip (Aventis Pasteur). The main outcome measure was the risk difference in ORS symptoms in the 24 hours after receiving the vaccine and after receiving placebo. RESULTS: Recurrence attributable to the vaccine occurred in 34% (95% confidence interval, 21%-47%) of patients after receiving Fluviral S/F and in 15% (95% confidence interval, 2%-28%) after receiving Vaxigrip. The rate was twice as high in group A vs groups B and C. The risk of ORS was highest and most significant in group A patients vaccinated with Fluviral S/F. Most cases were mild, with 94% of patients with recurrence indicating that they would still be revaccinated the next year. CONCLUSIONS: Despite high recurrence rates, revaccination of persons previously affected by ORS seems to be safe. Oculorespiratory syndrome is not anaphylactic, and most recurrences are benign. Most patients remain willing to be revaccinated.


Asunto(s)
Infecciones del Ojo/etiología , Vacunas contra la Influenza/efectos adversos , Gripe Humana/prevención & control , Infecciones del Sistema Respiratorio/etiología , Vacunación/efectos adversos , Adolescente , Adulto , Distribución por Edad , Anciano , Canadá/epidemiología , Estudios Cruzados , Infecciones del Ojo/diagnóstico , Infecciones del Ojo/epidemiología , Femenino , Humanos , Vacunas contra la Influenza/administración & dosificación , Masculino , Persona de Mediana Edad , Probabilidad , Recurrencia , Valores de Referencia , Infecciones del Sistema Respiratorio/diagnóstico , Infecciones del Sistema Respiratorio/epidemiología , Medición de Riesgo , Índice de Severidad de la Enfermedad , Distribución por Sexo , Síndrome , Vacunación/métodos
17.
Can J Public Health ; 96(4): 269-72, 2005.
Artículo en Francés | MEDLINE | ID: mdl-16625793

RESUMEN

CONTEXT: The Quebec Public Health Act provides for the creation of a central vaccination registry. However, details of how such a registry would be used have not been established. This study seeks to document the opinion of both the public and of health workers about the usefulness of the registry, consent for enrolment, access to the data and the right of withdrawal. METHODS: Individual interviews and discussion groups were held with parents, senior citizens and health workers. The material collected was recorded, transcribed and analyzed qualitatively using MAXQDA software. RESULTS: The usefulness of a vaccination registry seems to meet with general agreement, as does the idea of obtaining broad-based consent at enrolment. However, this consensus starts to crumble on questions of determining the rules governing access to the registry. Some favour limited consent, authorizing each access, while others, more numerous, prefer a broad-based consent giving access to all individuals authorized under the law. Opinions are even more divided on the question of giving the user the right to not record certain vaccines, particularly when they may be considered sensitive and a possible cause of prejudice. DISCUSSION: The more the information is considered sensitive by users, the more they seek to have access to the register and entries into it controlled and to apply some kind of specific consent, limited in scope, rather than a broad-based consent. This study lets us draw lessons applicable to the computerization and networking of medical records.


Asunto(s)
Actitud del Personal de Salud , Actitud Frente a la Salud , Programas de Inmunización/estadística & datos numéricos , Consentimiento Informado , Sistema de Registros , Vacunación/estadística & datos numéricos , Acceso a la Información , Humanos , Entrevistas como Asunto , Programas Nacionales de Salud , Quebec
18.
Can J Public Health ; 96(4): 273-7, 2005.
Artículo en Francés | MEDLINE | ID: mdl-16625794

RESUMEN

INTRODUCTION: Nurses carry out essential functions in the area of immunization in Québec and their role has broadened considerably since January 2003, following legislative modifications. However, the training received may not always allow nurses to fill this role satisfactorily. This study seeks to document the training in immunization offered to Québec nurses in the workplace. METHOD: A questionnaire was mailed to the directors or heads of nursing care (DSI/RSI) in 477 health care establishments in Québec in March 2003. RESULTS: Health care establishments in Québec offer more training to nurses on the job (68%) than at the moment of hiring (43%). These percentages vary widely according to the type of establishment. More than 90% of the local community service centres (CLSC) that responded offer training to their nurses. The indications/contraindications of immunization products and emergencies related to vaccination represent the themes most frequently dealt with. Only 38% of respondents affirm that the nurses in their institution are "very favourable" to vaccination. DISCUSSION: Almost all Québec CLSCs, which is where most immunization activities are carried out, offer training in vaccination to their nurses. On the other hand, few hospital centres (CH) and long-term care establishments (CHSLD) do so. Further documentation should be carried out on the impact of less than optimal training on the promotion of immunization programs by nurses.


Asunto(s)
Programas de Inmunización , Capacitación en Servicio , Personal de Enfermería/educación , Vacunación/métodos , Lugar de Trabajo , Actitud del Personal de Salud , Centros Comunitarios de Salud , Humanos , Programas Nacionales de Salud , Personal de Enfermería/psicología , Quebec , Encuestas y Cuestionarios , Vacunación/efectos adversos , Recursos Humanos
19.
Clin Infect Dis ; 36(7): 850-7, 2003 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-12652385

RESUMEN

In 2000, an influenza vaccine was associated with unusual ocular and respiratory symptoms (known as "oculorespiratory syndrome" [ORS]) that possibly were due to numerous microaggregates of unsplit viruses present in the product. We assessed the potential for an improved vaccine formulation (for use in 2001-2002) to cause ORS and other symptoms in adults, using a double-blind, randomized, crossover study design. Symptoms were ascertained 24 h after 622 doses of vaccine and 626 doses of saline placebo were injected. The risk of ORS was 6.3% after vaccine injection and 3.4% after placebo injection, which yielded a significant vaccine-attributable risk of 2.9% (95% confidence interval, 0.6-5.2). ORS symptoms were mild. Significant differences in risk after injection of vaccine versus placebo existed for ocular soreness and/or itching (2.4%), coughing (1.6%), and hoarseness (1.2%). Vaccine-attributable general symptoms were infrequent. We conclude that certain mild oculorespiratory symptoms were triggered by an influenza vaccine that was otherwise minimally reactogenic and, hence, that such symptoms might be associated with influenza vaccines in general.


Asunto(s)
Tos/etiología , Oftalmopatías/etiología , Vacunas contra la Influenza/efectos adversos , Vacunas de Productos Inactivados/efectos adversos , Adulto , Distribución por Edad , Estudios Cruzados , Método Doble Ciego , Femenino , Ronquera/etiología , Humanos , Masculino , Persona de Mediana Edad
20.
Clin Infect Dis ; 37(8): 1059-66, 2003 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-14523770

RESUMEN

During the 2000-2001 influenza immunization campaign in Canada, an oculorespiratory syndrome (ORS) was recognized as adverse event associated with one of the vaccines administered. The initial surveillance case definition for ORS in 2000-2001 specified onset within 24 h after vaccination and resolution within 48 h after onset; the restriction on the duration of ORS was removed from the case definition for the vaccine distributed during the 2001-2002 influenza season. The implicated vaccine contained large aggregates of unsplit virions; alterations to the manufacturing process for the vaccine distributed during 2001-2002 addressed this. A randomized, double-blind, placebo-controlled trial assessed the safety of the reformulated version in previously affected adults. The trial was halted early, after 61 participants had received an injection (34 had received vaccine, and 27 had received placebo). The vaccine-attributable recurrence rate for onset of ORS within 24 h after injection was 33% (95% confidence interval [CI], 10%-53%); for cases that resolved within 48 h, this rate was 27% (95% CI, 5%-47%). Previously affected persons should be informed of the risk of ORS recurrence but also that episodes of such recurrence are mild and well tolerated.


Asunto(s)
Oftalmopatías/etiología , Vacunas contra la Influenza/efectos adversos , Enfermedades Respiratorias/etiología , Adulto , Anciano , Método Doble Ciego , Oftalmopatías/epidemiología , Femenino , Humanos , Vacunas contra la Influenza/administración & dosificación , Gripe Humana/prevención & control , Masculino , Persona de Mediana Edad , Recurrencia , Enfermedades Respiratorias/epidemiología , Factores de Riesgo , Síndrome
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