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fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Publisher: Cambridge University Press
Languages: English
Types: Article
Subjects: RA0421
Vaccine escape variants of hepatitis B virus (HBV) have been identified world-wide. A mathematical model of HBV transmission is used to investigate the potential pattern of emergence of such variants. Attention is focused on The Gambia as a country with high quality epidemiological data, universal infant immunization and in which escape mutants after childhood infections have been observed. We predict that a variant cannot become dominant for at least 20 years from the start of vaccination, even when using a vaccine which affords no cross protection. The dominant factor responsible for this long time scale is the low rate of infectious contacts between infected and susceptible individuals (we estimate the basic reproduction number of hepatitis B in The Gambia to be 1·7). A variant strain that achieves high prevalence will also take many years to control, and it is questionable whether emergence will be identifiable by sero-surveillance until of high prevalence. The sensitivity of the model predictions to epidemiological and demographic factors is explored.
  • The results below are discovered through our pilot algorithms. Let us know how we are doing!

    • 1. McMahon G, Ehrlich PH, Moustafa ZA, et al. Genetic alterations in the gene encoding the major HBsAg : DNA and immunological analysis of recurrent HBsAg derived from monoclonal antibody-treated liver transplant patients. Hepatology 1992 ; 15 : 757±66.
    • 2. Cariani E, Ravaggi A, Fiordalisi G, et al. Emergence of a novel HBsAg escape mutant in a liver-transplant recipient. Hepatology 1994 ; 20 : A307-A.
    • 3. Cariani E, Ravaggi A, Tanzi E, et al. Emergence of hepatitis-B virus S-gene mutant in a liver-transplant recipient. J Med Virol 1995 ; 47 : 410±5.
    • 4. Ngui SL, O'Connell S, Eglin RP, Heptonstall J. Low detection rate and maternal provenance of hepatitis B virus S gene mutants in cases of failed postnatal immunoprophylaxis in England and Wales. J Infect Dis 1997 ; 176 : 1360±5.
    • 5. Carman WF, Zanetti AR, Karayiannis P, et al. Vaccineinduced escape mutant of hepatitis B virus. Lancet 1990 ; 336 : 325±9.
    • 6. Oon CJ, Lim GK, Ye Z, et al. Molecular epidemiology of hepatitis B virus vaccine variants in Singapore. Vaccine 1995 ; 13 : 699±702.
    • 7. Carman WF, Korula J, Wallace L, MacPhee R, Mimms L, Decker R. Fulminant reactivation of hepatitis B due to envelope protein mutant that escaped detection by monoclonal HBsAg ELISA. Lancet 1995 ; 345 : 1406±7.
    • 8. Okamoto H, Yano K, Nozaki Y, et al. Mutations within the S gene of hepatitis B virus transmitted from mothers to babies immunized with hepatitis B immune globulin and vaccine. Pediatr Res 1992 ; 32 : 264±8.
    • 9. Fortuin M, Karthigesu V, Allison L, et al. Breakthrough infections and identi®cation of a viral variant in Gambian children immunized with hepatitis B vaccine. J Infect Dis 1994 ; 169 : 1374±6.
    • 10. Ogata N, Miller RH, Ishaka KG, Zanetti AR, Purcell RH. Genetic and biological characterization of two hepatitis B variants : a precore mutant implicated in fulminant hepatitis and a surface mutant resistant to immunoprophylaxis. International Symposium on Viral Hepatitis and Liver Disease, 1994 ; 238±42.
    • 11. Ghendon Y. WHO strategy for the global elimination of new cases of hepatitis B. Vaccine 1990 ; 8 : S134±8.
    • 12. Edmunds WJ, Medley GF, Nokes DJ. The transmission dynamics and control of hepatitis B virus in The Gambia. Stat Med 1996 ; 15 : 2215±33.
    • 13. McLean AR. Vaccination, evolution and changes in the efficacy of vaccines ± a theoretical framework. Proc R Soc Lond B Biol Sci 1995 ; 261 : 389±93.
    • 14. Wilson JN, Nokes DJ, Carman WF. The predicted pattern of emergence of vaccine-resistant hepatitis B : a cause for concern? Vaccine 1999 ; 17 : 973±8.
    • 15. Edmunds WJ, Medley GF, Nokes DJ, Hall AJ, Whittle HC. The in¯uence of age on the development of the hepatitis B carrier state. Proc R Soc Lond B Biol Sci 1993 ; 253 : 197±201.
    • 16. Anderson RM, May RM. Infectious diseases of humans : dynamics and control. Oxford : Oxford Science Publications, 1991.
    • 17. McLean AR, Blumberg BS. Modelling the impact of mass vaccination against hepatitis B. I. Model formulation and parameter estimation. Proc R Soc Lond B Biol Sci 1994 ; 256 : 7±15.
    • 18. McLean AR, Nowak MA. Competition between zido vudine-sensitive and zidovudine-resistant strains of HIV. AIDS 1992 ; 6 : 71±9.
    • 19. McLean AR, Blower SM. Imperfect vaccines and herd immunity to HIV. Proc R Soc Lond B Biol Sci 1993 ; 253 : 9±13.
    • 20. Whittle HC, Maine N, Pilkington J, et al. Long-term efficacy of continuing hepatitis B vaccination in infancy in two Gambian villages. Lancet 1995 ; 345 : 1089±92.
    • 21. Edmunds WJ, Medley GF, Nokes DJ. Vaccination against hepatitis B virus in highly endemic areas : waning vaccine-induced immunity and the need for booster doses. Trans R Soc Trop Med Hyg 1996 ; 90 : 436±40.
    • 22. Edmunds WJ, Medley GF, Nokes DJ, O'Callaghan CJ, Whittle HC, Hall AJ. Epidemiological patterns of hepatitis B virus (HBV) in highly endemic areas. Epidemiol Infect 1996 ; 117 : 313±25.
    • 23. Population and Housing Census (1983). The Republic of The Gambia, 1987.
    • 24. Anderson RM, May RM. Age-related changes in the rate of disease transmission : implications for the design of vaccination programmes. J Hyg 1985 ; 94 : 365±436.
    • 25. Edmunds WJ. The epidemiology and control of hepatitis B virus in highly endemic areas. Ph.D. thesis, Department of Biology, Imperial College, London, 1994.
    • 26. Girones R, Miller RH. Mutation rate of the hepadnavirus genome. Virology 1989 ; 170 : 595±7.
    • 27. Nowak M, May RM. Superinfection and the evolution of parasite virulence. Proc R Soc Lond B Biol Sci 1994 ; 255 : 81±9.
    • 28. Andreasen V, Pugliese A. Pathogen coexistence induced by density-dependent host mortality. J Theor Biol 1995 ; 177 : 159±65.
    • 29. White LJ, Cox MJ, Medley GF. Cross immunity and vaccination against multiple microparasite strains. IMA J Math Appl Med Biol 1998 ; 15 : 211±33.
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