Bollettino epidemiologico nazionaleSEIEVA: Epidemiologic surveillance of acute viral hepatitis Highlights from the 5th SEIEVA workshop
Editor’s note: This article consists of summaries of several studies presented at the workshop as well as summaries of major hepatitis articles from the English-language literature. Below are highlights of the studies presented at the workshop.
The fifth biennial workshop of SEIEVA was held between November 30 and December 2, 2000. Below are selected highlights of SEIEVA studies presented at the meeting as well as Tables showing incidence of the various forms of hepatitis in Italy.
Epidemiology and Prevention of Hepatitis A
For 1999, the most recent year for which data are available, there has been a clear reduction in the incidence of hepatitis A. The 1999 incidence was 3/100,000, similar to the level reported in the past during non-epidemic periods. For the past several years, levels have been high because of a prolonged epidemic in southern Italy that has particularly affected the Puglia region. As in the past, the most important risk factor for hepatitis A was consumption of seafood (70% of the cases), followed by travel, especially for residents of northern Italy traveling to southern Italy or overseas (20%), and contact with a jaundiced individual (14%).
The epidemic in Puglia originally was linked with consumption of seafood, although subsequently transmission was person-to-person. In 1996-1997, the incidence exceeded 130 cases/100,000 residents. Since 1998, the incidence has decreased considerably. Following the epidemic, Puglia began a vaccine campaign in children 15-18 months of age and in adolescents. While only low coverage was achieved in the young children, coverage levels of 86%-96% were achieved in the adolescents, largely as a secondary result of a mandatory hepatitis B vaccine program targeting this age group. The surveillance results underline the need for vaccination of recommended groups, good environmental hygiene, and the importance of knowing the origin of seafood being purchased and consumed.
Guidelines for Hepatitis A Vaccine
The Istituto Superiore di Sanità has developed a working group on the use of hepatitis A vaccine for public health officials and physicians. The project has multiple phases that are in course; the steps and intended content of the guidelines are detailed in the article.
Hepatitis and Invasive Procedures
SEIEVA data for 1994-1998 were used to estimate the risks of acquiring hepatitis B or C associated with invasive procedures. For purposes of the analysis, all subjects under the age of 15, those who were intravenous drug users, and those with transfusion-associated hepatitis were excluded from the analysis. The 2651 cases of acute hepatitis B and 908 cases of acute hepatitis C were compared against the 6607 cases of hepatitis A, controlling for age.
Almost all the invasive procedures were associated with an increased risk of hepatitis B and C. For hepatitis B, the greatest risks were associated with abdominal surgery (OR 4.6), eye surgery (mostly cataract operations; OR = 4.3), urologic procedures (OR = 3.9), and dental procedures (OR = 3.7). With respect to hepatitis C, the OR for eye surgery was 23.1, 15.4 for gynecologic surgery, and 13.9 for cardiovascular surgery. Biopsies and endoscopic procedures were also significantly associated with hepatitis C. These results underline the need for good universal precautions and appropriate procedures for maintaining and sterilizing equipment.
Vaccination of HBsAG+ Mothers
To evaluate the protective efficacy and long term immunogenicity of the hepatitis B vaccine, the persistence of protective antibody levels against HBV and the incidence of infection with wild or mutant HBV were assessed in newborns of HbsAG positive mothers. The newborns in the study had received post-exposition prophylaxis with immunoglobins and were vaccinated at birth. Among the 522 neonates, born between 1985 and 1994 in 3 hospitals in the Campania region of southern Italy and followed up in 1997 and 1998, 17 were naturally infected with the virus (anti-HBc positive), of whom 3 developed chronic infection (HbsAg and HBV-DNA positive). Two of the 3 had wild virus that was e minus and was identical to that found in their mothers; the remaining infant had an e positive wild strain with a double amino acid substitution of the a determinant of the s gene (P120S, P127S). Of the 505 who had been immunized but were not infected, 400 (79%) were still protected with antibody titers > 10 mU/ml, while in the remaining 105 (21%), levels were not measurable. These data indicate that the protective mid- and long-term efficacy of the hepatitis A vaccine is good and that the risk of infection in children born and living with HbsAg-positive mothers was reduced.
Drug-induced Hepatitis
Since 1997, SEIEVA has also studied hepatitis resulting from administration of drugs. Between 1997 and 1999, the relative frequency of non-A, non-B non-C was 2.3% (265 cases); although in 40% of these cases (104), data were missing on the use of drugs. Thirty-four percent of cases (55 cases) for whom the variable had been completed had consumed a drug, but the type of drug consumed had not been specified. The data were therefore judged inadequate to perform an appropriate analysis. Nonetheless, the variable has been left on the SEIEVA data form and efforts are being made to improve its completion and quality.
Discordance between Surveillance Systems for Acute Hepatitis
Two regions (Piedmont and Puglia) have linked records from the acute infectious disease surveillance system (SIMI), SEIEVA, and the regional hospital discharge data base (SDO). The Puglia study analyzed hepatitis A data for 1997 to 1999, while Piedmont analyzed hepatitis A and B data for 1998. Discrepancies were found, with overestimates by the SDO system due to inclusion of non-acute cases and underestimates in the SEIEIVA system because of problems with data flow. In addition, there was discordance in the case definitions caused by differences in diagnostic criteria. Ed note: see the July/August issue of the BEN for details of the Puglia analysis.
Tables: INCIDENCE OF ACUTE VIRAL HEPATITIS. SEIEVA 2000
