Chronic HBV infection, with the attendant risk of cirrhosis and hepatocellular carcinoma, occurs in 1%-5% of adults and up to 90% of infants who are infected with HBV.3-5 Providing vaccinations during adolescence without offering vaccinations during infancy misses this critical period when the acquisition of a HBV infection can be the most harmful. Epidemiologic studies show that the age distribution of HBV varies by jurisdiction and suggest that roughly one-third of chronic infections are acquired during infancy and early childhood.6-9 An ideal vaccine schedule should protect against infection both in infancy, when the risk of becoming a chronic HBV carrier is highest, and in adolescence, when high-risk sexual and drugusing behaviours occur more frequently.Epidemiologic data are critical for informing decisions about vaccination. Estimating the age-specific incidence of acute infections is valuable for planning prevention measures. However, acute infections in infants and toddlers may be missed because HBV infection is often asymptomatic in young children. In many jurisdictions, the age-specific incidence of HBV infection is unknown.The controversy surrounding booster injections stems in part from the rapid drop in antibodies after completion of the primary series of injections. Serum levels of antibodies against hepatitis B surface antigen have been used to measure the initial response to vaccination (antibody levels ≥ 10 IU/L are considered protective). This marker measures response to the vaccine within the first few weeks but is not an appropriate indicator of long-term immunity. Serologic studies have shown that the titre of antibodies against hepatitis B surface antigen drops within the first few years after vaccination and that one-third to one-half of children vaccinated as infants will have titres below 10 IU/L by 10-15 years of age. [10][11][12] This has been misinterpreted to mean that population-level protection shows a similar dramatic drop.Long-term observational data show that vaccinated individuals -even those who have an undetectable titre of hepatitis B surface antigen -can mount an anamnestic response to contact with HBV.11,13 A recent booster trial performed 18 years after vaccination of infants in Gambia provides further evidence of persistent immunity.14 Although almost 70% of participants had no detectable antibodies at baseline, of the 181 participants who were tested 2 weeks after receiving a booster dose, 92.3% (95% CI 87.4-95.7) showed an early anamnestic response.14 The geometric mean concentration of antibodies against hepatitis B surface antigen in this group rose to 524 IU/L (95% CI 441-621), which suggests that most people who have been vaccinated can mount a protective immune response even 18 years after receiving a primary series of vaccinations in infancy. Universal vaccination of infantsAs of 2007, 171 of the 193 member countries of the World Health Organization (WHO) had implemented the recommendations of the Expanded Programme on Immunization to offer universal hepatitis B ...

BackgroundThe province of Ontario, Canada initiated mass immunization clinics with adjuvanted pandemic H1N1 influenza vaccine in October 2009. Due to the scale of the campaign, temporal associations with Guillain-Barré syndrome (GBS) and vaccination were expected. The objectives of this analysis were to estimate the number of background GBS cases expected to occur in the projected vaccinated population and to estimate the number of additional GBS cases which would be expected if an association with vaccination existed. The number of influenza-associated GBS cases was also determined.MethodsBaseline incidence rates of GBS were determined from published Canadian studies and applied to projected vaccine coverage data to estimate the expected number of GBS cases in the vaccinated population. Assuming an association with vaccine existed, the number of additional cases of GBS expected was determined by applying the rates observed during the 1976 Swine Flu and 1992/1994 seasonal influenza campaigns in the United States. The number of influenza-associated GBS cases expected to occur during the vaccination campaign was determined based on risk estimates of GBS after influenza infection and provincial influenza infection rates using a combination of laboratory-confirmed cases and data from a seroprevalence study.ResultsThe overall provincial vaccine coverage was estimated to be between 32% and 38%. Assuming 38% coverage, between 6 and 13 background cases of GBS were expected within this projected vaccinated cohort (assuming 32% coverage yielded between 5-11 background cases). An additional 6 or 42 cases would be expected if an association between GBS and influenza vaccine was observed (assuming 32% coverage yielded 5 or 35 additional cases); while up to 31 influenza-associated GBS cases could be expected to occur. In comparison, during the same period, only 7 cases of GBS were reported among vaccinated persons.ConclusionsOur analyses do not suggest an increased number of GBS cases due to the vaccine. Awareness of expected rates of GBS is crucial when assessing adverse events following influenza immunization. Furthermore, since individuals with influenza infection are also at risk of developing GBS, they must be considered in such analyses, particularly if the vaccine campaign and disease are occurring concurrently.

Physical inactivity is a leading risk factor for non-communicable diseases (NCDs) and early mortality. Family physicians have an important role in providing physical activity counselling to patients to help prevent and treat NCDs. Lack of training on physical activity counselling is a barrier in undergraduate medical education, yet little is known regarding physical activity teaching in postgraduate family medicine residency. We assessed the provision, content and future direction of physical activity teaching in Canadian postgraduate family medicine residency programs to address this data gap. Fewer than half of Canadian Family Medicine Residency Programme directors reported providing structured physical activity counselling education to residents. Most directors reported no imminent plans to change the content or amount of teaching. These results reflect significant gaps between the recommendations of WHO, which calls on doctors to prescribe physical activity, and the current curricular content and needs of family medicine residents. Almost all directors agreed that online educational resources developed to assist residents in physical activity prescription would be beneficial. By describing the provision, content and future direction of physical activity training in family medicine, physicians and medical educators can develop competencies and resources to meet this need. When we equip our future physicians with the necessary tools, we can improve patient outcomes and do our part to reduce the global epidemic of physical inactivity and chronic disease.