8615 © Saturday 8 October 1988 TRIAL OF HIGH-DOSE EDMONSTON-ZAGREB MEASLES VACCINE IN GUINEA-BISSAU: PROTECTIVE EFFICACY PETER AABY HENRIK LYNGBECK HANSEN JESPER THÅRUP MORTEN SODEMANN THØGER GORM JENSEN HANS KRISTIANSEN ANJA POULSEN MARIANNE JAKOBSEN KIM KNUDSEN MARIA CLOTILDE DA SILVA1 HILTON WHITTLE2 Institute of Ethnology and Anthropology and Statistical Research Unit, University of Copenhagen, Denmark; International Medical Cooperation Committee, Copenhagen; Maternal and Child Health Programme, Ministry of Public Health, Guinea-Bissau;1 and Medical Research Council Laboratories, Fajara, The Gambia2 Summary In a randomised study of 558 children in an urban African community, the protective effect of the Edmonston-Zagreb (EZ) measles vaccine given in a dose of 40 000 plaque forming units from the age of 4 months was compared with the effects of a standard dose (6000 tissue culture infectious units) of Schwarz measles vaccine given from the age of 9 months. During two years of follow-up, all 14 clinical cases of measles occurred in the Schwarz group; 10 of the children contracted measles before vaccination and 4 after measles vaccination. Thus the EZ vaccine provided significant protection against measles both before and after the usual age of vaccination. Among the children who were exposed to measles at home, those given EZ vaccine were better protected than either unvaccinated children or those given the Schwarz vaccine. Introduction SEVERAL previous studies in Bandim, a district of Bissau, Guinea-Bissau, have shown that the current strategy of measles immunisation does not control measles infection adequately.l Many children contract measles before 9 months of agel and in many the infection develops after they have received the Schwarz attenuated measles vaccine.2 In this community, we have therefore examined whether the Edmonston-Zagreb (EZ) vaccine administered from the age of 4 months3,4 controls measles better than the Schwarz vaccine given from the age of 9 months. Subjects and Methods Background The child health project in Bandim was started in 1978. As part of the study, local assistants make monthly visits to all houses in the 8 zones of Bandim to register pregnancies, births, and deaths. Every third month, children under three years of age are called for weighing and vaccination in their neighbourhood. The work in Bandim has been supervised by Danish medical students. Other studies in Bandim have examined the measles case fatality rate and the impact of measles vaccination.5,6 In January, 1985, just before the initiation of the EZ study, measles immunisation coverage with Schwarz vaccine was 84% (615 of 731) for children aged 12-35 months. Study Design The study began in February, 1985. Children born between Aug 1, 1984, and Sept 31, 1985, who had been registered in Bandim before 4 months of age were randomised to receive the EZ vaccine (EZ group) or the Schwarz vaccine (SW group). In addition to the Extended Programme of Immunisation (EPI) vaccines (BCG, diphtheria/pertussis/tetanus, and poliomyelitis) from the age of 4 months the EZ group received EZ measles vaccine and the SW group received an inactivated poliomyelitis vaccine (IPV) (kindly donated by Institut Merieux). From the age of 9 months, children in the EZ group received IPV and those in the SW group were given the Schwarz measles vaccine. Children were called for vaccination every month until they received these vaccines. If not vaccinated before age 9 months, children of both groups then received only one vaccine, this being either the EZ or the Schwarz measles vaccine. Blood samples taken by finger prick were collected before the first (at age 4 months or over) and second vaccinations (at 9 months or over) and again at 18 months. We followed the vaccinated children to assess the protection conferred against measles and to measure their serological responses. Measles vaccinations were noted on the health card, and other health centres were asked not to revaccinate the child against measles. Children vaccinated elsewhere against measles were excluded from the study. Since we could not guarantee that children in the control (SW) group would be vaccinated against measles if they moved out of the area, a double blind design was judged impossible. Before the start and midway through the study (March, 1986), at meetings in each of the 8 zones of Ban dim, the study was explained as a trial of two new and possibly better vaccines against measles and poliomyelitis. Before the first vaccination at 4 months, consent was obtained from the child’s mother or guardian. Only one mother refused to have her child vaccinated, and 5 refused the collection of blood samples. The study was approved by Guinea-Bissau’s Ministry of Health and by The Gambia Government/Medical Research Council ethical committee. Vaccines and Serology Children in the EZ group received a dose of 40 000 plaque forming units (pfu) of the EZ vaccine (lot 529) 4 and the children in the control group received a standard dose of the attenuated Schwarz measles vaccine (6000 tissue culture infectious units