A multicentre trial of live attenuated varicella vaccine in children with leukaemia in remission.
Two hundred forty children with acute leukaemia in remission for at least 1 year were immunized with live attenuated varicella vaccine. All were susceptible to varicella before immunization. There was a seroconversion to varicella-zoster virus in approximately 85% after 1 dose, and in 97% after 2 doses. The major side effect was mild to moderate rash, seen mainly in children with maintenance chemotherapy suspended for 1 week before and 1 week after vaccination. Vaccinees with rash were at some risk (10%) to transmit vaccine virus to varicella susceptibles with whom they had close contact. Twenty-nine vaccinees were subsequently exposed to varicella in their households. The attack rate of clinical varicella in these vaccinees was 21%, which is significantly lower than the 80%-90% attack rate occurring in varicella susceptibles after household exposure. All these breakthrough cases of varicella were mild, even in leukaemics receiving chemotherapy. Varicella vaccine was approximately 80% effective in preventing clinical varicella in children with leukaemia and completely effective in preventing severe varicella in this high-risk group.
D000208:Acute Disease; D002644:Chickenpox / Q000453:epidemiology / Q000517:prevention & control*; D019433:Chickenpox Vaccine; D002648:Child; D014645:Herpesvirus 3, Human / Q000276:immunology*; D006801:Humans; D007165:Immunosuppression Therapy; D007938:Leukemia / Q000276:immunology*; D011379:Prognosis; D014613:Vaccines, Attenuated / Q000009:adverse effects; D014765:Viral Vaccines / Q000009:adverse effects
D019433:Chickenpox Vaccine; D014613:Vaccines, Attenuated; D014765:Viral Vaccines