EPIDEMIC HEPATITIS-E IN PAKISTAN - PATTERNS OF SEROLOGIC RESPONSE ANDEVIDENCE THAT ANTIBODY TO HEPATITIS-E VIRUS PROTECTS AGAINST DISEASE

IgM and IgG anti-hepatitis E virus (HEV) patterns were determined in s era collected during a hepatitis outbreak in Pakistan. HEV infection w as detected serologically in 122 patients. IgM anti-HEV was detected i n specimens collected up to 2 weeks before and 5-7 weeks after hospita lization in 91% and 100%, respectively, of 122 HEV-infected patients. IgG followed a similar pattern. Peak antibody titers appeared 2-4 week s after hospitalization. At 20 months after hospitalization, IgM anti- HEV was not detected in any of 33 patients; IgG was found in all. Ige anti-HEV appeared to be protective in contacts of patients. This study confirms HEV as the cause of the outbreak, quantifies IgM and IgG ant i-HEV responses, provides evidence that Ige anti-HEV protects against hepatitis E, and demonstrates that Ige anti-HEV persists, but at dimin ished titer, after infection. Hepatitis E in young adults is the resul t of primary infection with HEV and, if reinfection occurs, it does no t commonly cause serious illness.