Hepatitis A incidence rate estimates from a pilot seroprevalence survey in Rio de Janeiro, Brazil.
(1/85)
BACKGROUND: To assess the impact of water sanitation and sewage disposal, part of a major environmental control programme in Rio de Janeiro, we carried out sero-prevalence studies for Hepatitis A virus (HAV) in three micro-regions in Rio de Janeiro. Each region varied with regard to level of sanitation. We are interested in assessing the discriminating power of age-specific prevalence curves for HAV as a proxy for improvement in sanitation. These curves will serve as baseline information to future planned surveys as the sanitation programme progresses. METHODS: Incidence rate curves from prevalence data are estimated parametrically via a Weibull-like survival function, and non-parametrically via maximum likelihood and monotonic splines. Sera collected from children and adults in the three areas are used to detect antibodies against HAV through ELISA. RESULTS: We compare baseline incidence curves at the three sites estimated by the three methods. We observe a strong negative correlation between level of sanitation and incidence rates for HAV infection. Incidence estimates yielded by the parametric and non-parametric approaches tend to agree at early ages in the microregion showing the best level of sanitation and to increasingly disagree in the other two. CONCLUSION: Our results support the choice of HAV as a sentinel disease that is associated with level of sanitation. We also introduce monotonic splines as a novel non-parametric approach to estimate incidence from prevalence data. This approach outperforms current estimating procedures. (+info)
Prevention of hepatitis A through active or passive immunization: Recommendations of the Advisory Committee on Immunization Practices (ACIP).
(2/85)
Routine vaccination of children is the most effective way to reduce hepatitis A incidence nationwide over time. Since licensure of hepatitis A vaccine in 1995, this strategy has been implemented incrementally, starting with the recommendation of the Advisory Committee on Immunization Practices (ACIP) in 1996 to vaccinate children living in communities with the highest rates of infection and disease. These updated recommendations represent the next phase of this hepatitis A immunization strategy. Vaccination of children living in states and communities with consistently elevated rates of hepatitis A will provide protection from disease and is expected to reduce the overall incidence of hepatitis A. This report updates the ACIP's 1996 recommendations on the prevention of hepatitis A through immunization (MMWR 1996;45:[No. RR-151) and includes a) new data about the epidemiology of hepatitis A; b) recent findings about the effectiveness of community-based hepatitis A vaccination programs; and c) recommendations for the routine vaccination of children in states, counties, and communities with rates that are twice the 1987-1997 national average or greater (i.e., > or = 20 cases per 100,000 population) and consideration of routine vaccination of children in states, counties, and communities with rates exceeding the 1987-1997 national average (i.e., > or = 10 but <20 cases per 100,000 population). Unchanged in this report are previous recommendations regarding the vaccination of persons in groups at increased risk for hepatitis A or its adverse consequences and recommendations regarding the use of immune globulin for protection against hepatitis A. (+info)
Inactivated hepatitis A vaccine in Chinese patients with chronic hepatitis B infection.
(3/85)
BACKGROUND: Hepatitis B (HBV)-infected patients have a higher morbidity and mortality when super-infected by hepatitis A (HAV). AIM: To evaluate the immunogenicity and safety of a commercial inactivated HAV vaccine in Chinese patients with chronic HBV infection. METHODS: Sixty-five HBV-infected patients (30 carriers, 22 chronic hepatitis, 13 cirrhosis), who were seronegative for HAV, received a dose of 1440 ELISA units of HAV vaccine at weeks 0 and 24. Twenty-eight healthy individuals aged 18-57 years, who were seronegative for both HBV and HAV infection, also received the same vaccination regimen. Seroconversion was defined as an anti-HAV titre >/= 33 mIU/mL. RESULTS: The seroconversion rates for the HBV-infected patients at weeks 2, 4 and 24 were 72, 91 and 80%, respectively. The corresponding geometric mean titres (GMTs) were 103, 311 and 123 mIU/mL. In the healthy control group the seroconversion rates were 86, 93 and 89% at weeks 2, 4 and 24. The corresponding GMTs were 112, 158 and 250 mIU/mL. There was no difference in the seroconversion rates between the two groups, but healthy controls had a significantly higher GMT at week 24 (P=0.04). Side-effects were more common in HBV patients. CONCLUSION: The HAV vaccine is equally efficacious in patients with chronic HBV infection. (+info)
Viral hepatitis: recent experiences from serological studies in Bangladesh.
(4/85)
Infections due to hepatitis A (HAV), hepatitis B (HBV), hepatitis C (HCV) and hepatitis E (HEV) viruses are the major causes of hepatitis and are associated with significant morbidity and mortality in developing countries like Bangladesh. The present study was carried out to determine the prevalence of HBsAg, anti-HCV antibody, anti-HAV antibody and anti-HEV antibody in patients suspected of having infection by HBV, HCV, HAV and HEV, respectively. Antibody to HAV was detected in 39% of subjects investigated. HBsAg was identified in 19% of subjects. Antibody to HCV and HEV was detected in 13% and 53% subjects, respectively. Infection with HAV was very high among children < or = 6 years of age (100%). On the contrary, exposure to HEV was higher in adult persons > or => 30 years of age (52%) compared to that in children < or = 6 years of age who had 0% incidence. Our study clearly indicates a high prevalence of those viruses, particularly of enterically transmitted HAV and HEV in Bangladesh, which appeared to be a serious health problem in this developing country. Control measures should be taken on an urgent basis to prevent the spread of infections by these viruses. (+info)
The prevalence of antibodies to hepatitis A virus and its determinants in The Netherlands: a population-based survey.
(5/85)
The prevalence of antibodies to hepatitis A virus was assessed in a Dutch nationwide sample (n = 7367). A questionnaire was used to study the association with various sociodemographic characteristics. Overall, 33.8% (95% CI 31.6-36%) of the population had hepatitis A antibodies. The seroprevalence was less than 10% in people under 35; it increased from 25% at 35 years to 85% at 79 years. For those 15-49 years of age, Turks (90.9%) and Moroccans (95.8%) had greater seroprevalence than autochthonous Dutch (20.2%) and other Western people (25%). Low or middle socio-economic status, as indicated by the highest educational level achieved, was associated with greater seroprevalence, independently of age and reported immunization (OR 2.11 and 1.45; 95% CI 1.67-2.67 and 1.11-1.89, respectively). These data suggest autochthonous Dutch and other Westerners born after World War II were exposed to hepatitis A during childhood less frequently than older birth cohorts. Thus, more susceptibility is likely in the coming decades. Since this means a greater risk of outbreaks in future years, and since morbidity and mortality are more frequent in older persons, studying the cost effectiveness of selective and general vaccination might be worthwhile. (+info)
The possible role of hepatitis A virus in the pathogenesis of atherosclerosis.
(6/85)
The possible association between hepatitis A virus (HAV) infection and coronary artery disease (CAD) was studied. Blood from 391 patients undergoing coronary angiography was tested for serum IgG antibodies to HAV and C-reactive protein (CRP). Of the 391 patients, 205 (52%) had anti-HAV IgG antibodies. CAD prevalence was 74% in HAV-seropositive and 52% in HAV-seronegative patients (P<.0001); significance persisted after adjustment for either traditional CAD risk factors or for risk factors plus other infectious agents (cytomegalovirus, Chlamydia pneumoniae, Helicobacter pylori, and herpes simplex virus). In addition, CRP levels were significantly higher in HAV-seropositive than in HAV-seronegative patients (P=. 013) in both univariate and multivariate analyses. Logistic regression analysis demonstrated that HAV seropositivity is an independent predictor of risk for CAD and elevated CRP levels. HAV infection is therefore associated with CAD, which raises the possibility that this virus may play a causal role in atherogenesis. (+info)
Screening travelers for hepatitis A antibodies: an observational cost-comparison study of vaccine use.
(7/85)
OBJECTIVES: To measure the seroprevalence of antibodies to hepatitis A virus (anti-HAV) in a health plan population of travelers and to determine whether prevaccination screening for anti-HAV can reduce unnecessary vaccination and thus promote the most effective, economic use of hepatitis A vaccine. DESIGN: Observational, cost-comparison study. SETTING: Central injection clinic of a health maintenance organization medical center. SUBJECTS: Five hundred twenty-seven adults who denied having previous hepatitis A or vaccination. MAIN OUTCOME MEASURES Subgroups with the greatest prevalence of anti-HAV seen between June 1995 and April 1996 for immunizations before traveling to nonindustrialized countries. Relative costs of their screening and immunization. RESULTS: The presence of anti-HAV precluded the need for vaccination in 148 subjects (28.1%). The highest prevalence of anti-HAV (82.7%) was found in subjects born in nonindustrialized countries (62/75), in subjects who had previously traveled to areas of endemic hepatitis A (32.1% [135/420]), and in subjects born before 1945 (29.2% [92/315]). Costs of screening and vaccinating travelers were cheapest if prevaccination antibody sera testing was limited to subjects born in nonindustrialized countries and those born before 1945. CONCLUSIONS: Prevaccination screening of travelers for hepatitis A can be done selectively on the basis of age and country of origin. This strategy could lead to a more economic use of the vaccine and clinic resources. (+info)
Prospective study of pathogen burden and risk of myocardial infarction or death.
(8/85)
BACKGROUND: We previously demonstrated that the risk of coronary artery disease (CAD) increased in relation to the number of pathogens (the "pathogen burden") in a cross-sectional study. In the present prospective study with a different patient cohort, we evaluated the effect of pathogen burden on the risk of myocardial infarction (MI) or death among CAD patients. METHODS AND RESULTS: IgG antibodies to cytomegalovirus (CMV), hepatitis A virus (HAV), herpes simplex virus type 1 (HSV1), HSV type 2 (HSV2), Chlamydia pneumoniae and Helicobacter pylori, and C-reactive protein (CRP) levels were tested in baseline blood samples from 890 patients who had significant CAD on angiography. The mean follow-up period was 3 years. The baseline prevalence of antibodies directed against CMV, HAV, HSV1, or HSV2, but not C pneumoniae and H pylori, was significantly higher among patients who subsequently developed MI or death than among control subjects. After adjustment for traditional risk factors, number of diseased vessels, and clinical presentation, relative hazards (95% confidence limits) for MI or death were 2.0 (1. 4 to 3.2) for CMV, 1.6 (1.1 to 2.3) for HAV, and 1.5 (1.0 to 2.2) for HSV2. Increasing pathogen burden was significantly associated with increasing risk of MI or death in a dose-response fashion. Adjusted relative hazards of MI or death associated with pathogen burden were significant among individuals with low or high CRP levels. CONCLUSIONS: The results suggest that infection plays an important role in incident MI or death and that the risk posed by infection is independently related to the pathogen burden. (+info)