MOLECULAR EPIDEMIOLOGY OF VARICELLA-ZOSTER VIRUS IN EAST LONDON, ENGLAND, BETWEEN 1971 AND 1995

The molecular epidemiology of varicella-zoster virus in London, Englan d, between 1971 and 1995 was examined by using two informative polymor phic markers, variable repeat region R5 and a Bg/I restriction site in gene 54, Viruses from 105 cases of chickenpox and 144 of zoster were typed, Two alleles of R5, A and B, were found at prevalences of 89 and 6%, respectively. No difference in allele frequency between the zoste r and chickenpox cases was found, and no change in the frequencies of these alleles was observed to occur over time, By contrast, a Bg/I res triction site (Bg/I+) was found with increasing frequency over time am ong cases of varicella (P < 0.005) and, to a lesser extent, cases of z oster, The Bg/I+ polymorphism was strongly associated (P < 0.0005) wit h zoster in subjects who had immigrated to the United Kingdom from cou ntries with low adult immunity to varicella (LAIV), Sixty-three percen t of the subjects with zoster who had emigrated from countries with LA IV carried the Bg/I+ virus, in contrast to 10% of adults who had grown up in countries with high adult immunity to varicella, The significan ce of these data, in view of the changing epidemiology of chickenpox, is discussed.