Systemic immediate-type reactions to gelatin included in Japanese encephalitis vaccines.

Three children had systemic immediate-type reactions to Japanese encephalitis (JE) vaccine which contains gelatin as a stabilizer. We found that all the children had anti-gelatin IgE in their sera. Further, two of the three also had experienced systemic allergic reactions to gelatin-containing foods before the vaccination. We assume that the systemic allergic reactions to JE vaccines might be caused by gelatin in the JE vaccine.