During the Gulf crisis many people moved temporarily to rural towns in the Riyadh Region of Saudi Arabia. Crowding and an overuse of water and sanitation facilities resulted. Hepatitis reports also increased. We sought to discover which risk factors contributed to the increased rate of hepatitis and to determine the effectiveness of immune globulin (IG) in preventing hepatitis.
Methodology
We selected two towns, Majmah and Zulfi, with the largest increases in hepatitis reports. We identified all hepatitis cases reported from primary health care centers (PHCCs) from July 1990 to September 1991. We tested sera from 24 recent cases for hepatitis A-specific IgM. We selected 45 control houses at random from complete listings of all houses in the same PHCC catchment areas as the case houses. We compared cases and controls for hepatitis A risk factors. We compared secondary attack rates in household contacts who received IG and in those who did not.
Results
All 24 sera from recent cases had hepatitis A-specific IgM. Highest attack rates were in 5- to 14-year-old children and lowest in persons older than 19 years. In Majmah case-persons were more likely than control-persons to report contact with a playmate with hepatitis (O.R. infinite, p<0.001) or to live in a household with poor sanitation (O.R.=4.4; 95% C.I. 1.4, 14) or crowding (O.R.=5.6, 95% C.I. 2.1, 15). In Zulfi, cases had the same risk factors. In addition, in Zulfi case-persons were more likely than control-persons to live in a house with a history of sewage overflow (O.R.=138; 95% C.I. 41, 510) or with temporary residents during the crisis (O.R.=9.4; 95% C.I. 3.6, 25). Of 825 household contacts who received IG, none developed hepatitis, compared with 46 (13%) of 363 household contacts who did not receive IG (p<0.001).
Conclusion
Crowding by temporary residents worsened an underlying situation in which many risk factors contribute to hepatitis A. IG was shown to be highly effective in preventing subsequent cases of hepatitis A in household contacts of cases.