Resistance of recent measles virus wild-type isolates to antibody-mediatedneutralization by vaccinees with antibody

The neutralization capacity of sera from Luxembourgian adolescent vaccinees and from Nigerian women with measles-induced immunity to a number of measl es virus strains was compared. Although both cohorts were matched for their hemagglutination inhibition and standard neutralization titers, 12 of the 22 late convalescent sera, and only 6 of 24 vaccinees neutralized all virus es. Similarly, only 2 of 20 viruses were not neutralized by at least 75% of late convalescent sera, in comparison to 10 of 20 viruses that resisted ne utralization by at least 75% of the vaccinees. The more resistant viruses w ere not limited to a certain clade. One Nigerian virus was resistant to neu tralization by 30% of the late convalescent women and by 75% of vaccinees. These results suggest that qualitative differences in neutralizing antibodi es may reduce further protection of infants by passively acquired immunity against wild-type viruses when vaccinated girls become mothers. J. Med. Vir ol. 62: 91-98, 2000. (C) 2000 Wiley-Liss, Inc.