A nosocomial outbreak of Crimean-Congo haemorrhagic fever at Tygerberg Hospital. Part IV. Preventive and prophylactic measures.

During the Crimean-Congo haemorrhagic fever (CCHF) outbreak at Tygerberg Hospital a particular problem existed: a simultaneous influenza epidemic complicated the screening of contacts because of its very similar clinical picture to that of early CCHF. The methods of identifying and screening contacts are described. Of 459 listed CCHF contacts, 7 (1,5%) developed the disease; 6 were contacts of the index case and only 1 a contact of a secondary case. Two of the 7 CCHF patients had no direct contact with the index case; this caused great concern about the dissemination, despite the otherwise full protective measures. Four of 46 blood contacts (8,7%) and 3 of 9 needle contacts (33%) developed the disease. Prophylactic interferon therapy had to be discontinued because of side-effects mimicking the symptoms of CCHF. Ribavirin was used prophylactically in 6 of the 9 inoculation contacts. One of the patients on ribavirin had a mild clinical course while 5 others who received the drug developed neither clinical CCHF nor antibodies to the virus. Two of the 3 needle contacts not treated with ribavirin had a severe clinical course. One contact with needle inoculation and 42 proven blood contacts who had not received ribavirin did not become infected. No firm conclusion can therefore be made about the protective value of prophylactic ribavirin.