Live attenuated varicella vaccine (Beijing Wantai Biopharmaceutical)

Varicella zoster virus (VZV) infections in human immunodeficiency virus (HIV)-infected patients are known to have a different disease spectrum from that seen in other types of patients. Varicella in children with HIV infection is likely to be more serious than in otherwise healthy children and routine antiviral therapy is recommended. There is evidence that the development of varicella in HIV-infected children is not associated with progression to AIDS, suggesting that it may be safe to immunize HIV-infected children with live attenuated varicella vaccine. There are no published data on varicella in HIV-infected adults, however, probably because most adults have already experienced varicella prior to HIV infection. Zoster in HIV-infected children differs somewhat from that in HIV-infected adults. In particular, HIV-infected children who develop varicella in the setting of severe immunodeficiency are at an especially high risk to develop zoster. Given the low rate of toxicity of aciclovir as well as its ease of administration and its efficacy in hastening the healing of VZV infections, prompt treatment with this antiviral agent is recommended for both HIV-infected children and adults. Foscarnet should be used for zoster that is strongly suspected or proven to be caused by aciclovir-resistant VZV. Patients with HIV for whom there is no evidence of significant immunosuppression and who have not had varicella should be immunized with live attenuated varicella vaccine as a preventative measure for both varicella and zoster. It is hoped that immunization of VZV seropositive HIV-infected patients will decrease the incidence of zoster. Studies to determine this are under way.

Live attenuated varicella vaccine was administered to healthy varicella-susceptible adults. Of 187 adults immunized with the Oka strain of vaccine, seroconversion to varicella-zoster virus (VZV) occurred in 82% after one dose and in 94% after two doses. Adverse effects were unusual. After immunization, one subject developed mild zoster caused by wild-type virus. Twelve adults developed a mild breakthrough case of chickenpox after exposure to VZV. Protection after household exposure was observed in nine (56%) of 16; however, the illness in all seven patients with breakthrough illness was modified, with an average of only 24 vesicles. Subjects seropositive at household exposure were unlikely to develop a breakthrough illness. Approximately 25% of vaccinees who seroconverted lost detectable antibodies to VZV after vaccination, but even those who became seronegative were partially protected. Varicella vaccine offered significant protection against severe chickenpox in healthy adults.