TYPHIM-VI VACCINE AGAINST TYPHOID-FEVER - A CLINICAL-TRIAL IN KENYA

Safety, tolerance and immunogenicity of the purified Vi polysaccharide vaccine (Typhim Vi) against typhoid fever was evaluated in primary sc hool children aged 5-15 years. A total of 435 children were vaccinated , each with a single intramuscular injection in the left deltoid muscl e. One hundred and ten children were randomly selected for blood sampl es on day 0 (pre vaccination) and day 30 (post vaccination). Vi antibo dies studied by Radio immune assay (RIA) on 97(88%) paired sera showed a seroconversion rate of 76.2% and seroprotection rate after vaccinat ion was 74.2%, while 6.2% of children already had protective immunity before vaccination. The vaccine was well tolerated, Most commonly repo rted reactions were mild pain at site of injection (83%), and a few co mplained of mild swelling (4.6%), induration (1.1%), itching (1.1%) an d headaches (1.4%). All reactions were of mild severity and disappeare d within 24 to 48 hours.