The presence of hepatitis A antibodies in dental workers. A seroepidemiologic study.

BACKGROUND: The licensing of hepatitis A vaccine in the United States and other countries in the 1990s raised the question of vaccine candidates. The authors undertook a study to evaluate the presence of antibodies against hepatitis A virus, or HAV, in dental workers. METHODS: The authors recruited 115 members of the dental staff of Tel Aviv University: 82 dentists, 21 dental assistants, eight dental hygienists and four laboratory technicians. The subjects completed a structured questionnaire regarding demographic information (such as age, sex, number of siblings, number of children) and occupational characteristics. Venous blood was obtained and examined for presence of immunoglobulin G antibodies to HAV by microparticle enzyme immunoassay. RESULTS: Univariant analysis (chi 2 and Student t test) and multivariate stepwise logistic regression analysis were used to identify variables that were associated with seropositivity. Greater number of years of occupation in dentistry were independently and significantly (P = .0004) associated with seropositivity to HAV. The calculated odds ratio showed that each year of work increased the likelihood of being seropositive by 1.06 (6 percent). Subjects tended to have higher seropositive rates if they were older, had a greater number of children, had a greater number of siblings, had worked in hospitals and worked with children (pediatric dentists and orthodontists). CONCLUSIONS: This study suggests that HAV can be considered a hazard to dental workers, with risk increasing as the number of years in dentistry increases. More studies with larger sample sizes are needed. CLINICAL IMPLICATIONS: As HAV infection is associated with morbidity and mortality, dentists--especially those working in areas of endemic HAV (such as Africa, Asia and Latin America)--are encouraged to consider receiving the active vaccine to prevent HAV infection.

Occupations at increased risk of hepatitis A: a 2-year nationwide historical prospective study.

The recent licensing of active hepatitis A vaccines raises the question of vaccine candidates. Although various groups of workers are at theoretical occupational risk of hepatitis A infection, no comprehensive quantitative data exist to determine which occupational groups should receive active vaccination. Therefore, the aims of this study were to identify occupations at risk for hepatitis A infection and to determine their relative risk. In this nationwide historical prospective study, the relative risk of hepatitis A among different occupations in Israel was determined according to the incidence of hepatitis A in different occupations during 1993 and 1994 compared with the incidence of hepatitis A in two standard populations. After age, gender, ethnicity, and time of immigration to Israel were controlled for, certain occupations showed a significant increased risk of hepatitis A: yeshiva students (standardized incidence ratio (SIR) = 9.98, 99% confidence interval: 7.55, 13.18), day care center and kindergarten staff (SIR = 5.47, 99% confidence interval: 3.50, 8.57), food industry workers (SIR = 5.41, 99% confidence interval: 1.92, 15.25), teachers (SIR = 4.02, 99% confidence interval: 2.92, 5.48), physicians and dentists (SIR = 3.77, 99% confidence interval: 1.78, 8.14), and therapists and medical technicians (SIR = 3.75, 99% confidence interval: 1.75, 8.14). Sewage workers and nurses did not show any significantly increased risk. The results were validated by comparison with an additional standard population. This first nationwide study identified occupations at risk of hepatitis A infection. It emerged that the authors' approach can provide a yardstick for measuring samples in both large and small countries that have a socioeconomic background similar to that of Israel.

[How valid is the official data from the Health Department on reported morbidity in Israel? Hepatitis A as an example].

Hepatitis A is one of the most frequently reported notifiable infectious diseases in Israel. The annual incidence as reported is around 70/100,000. The physician or the diagnostic laboratory notifies the district health office of the Ministry of Health. The purpose of this research was to evaluate the sensitivity of passive surveillance of hepatitis A morbidity among adults, 18 years and over. Methods included study of notifications to the Ministry of Health or hospitalizations of cases of hepatitis A and of positive laboratory tests results (IgM) for hepatitis A. We estimated the extent of under-reporting by 2 different methods of extrapolation. Data based on passive surveillance among the adult population, between 1.1.1993-31.12.1994, comprised less than 1/5 of the actual number of cases. Physicians notified about 6.2% of their hepatitis A patients. 5.1% of the notifications to the district health office were sent twice or more, usually both by the physicians and labs. The official data on hepatitis A morbidity, based on passive surveillance, are considerably underestimated. Physicians and public health officials should be aware that such data may not accurately reflect the magnitude of the risk or the amount of disease that can be prevented. Efforts should be made to improve this situation.