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The risk of zoster after varicella vaccination in children with leukemia
R Lawrence1, A A Gershon, R Holzman
1Department of Pediatrics, New York University Medical Center, New York.
Insights
Children with acute lymphoblastic leukemia vaccinated with varicella vaccine had a lower incidence of zoster compared to those with natural varicella infection. Zoster occurrence was not linked to leukemia relapse.
Area of Science:
- Pediatric Oncology
- Infectious Diseases
- Immunology
Background:
- Children with acute lymphoblastic leukemia (ALL) are susceptible to infections, including zoster (shingles).
- Live attenuated varicella vaccine is used in ALL patients in remission.
- The incidence of zoster after varicella vaccination in ALL children needs further investigation.
Purpose of the Study:
- To examine the incidence of zoster in children with ALL immunized with live attenuated varicella vaccine.
- To compare zoster incidence in vaccinated ALL children versus ALL children with natural varicella infection.
Main Methods:
- Prospective study of 346 children with ALL immunized with varicella vaccine.
- Matched-pair analysis comparing 84 vaccinated children with 84 children with natural varicella infection.
- Kaplan-Meier product-limit analysis to assess differences in zoster incidence.
Main Results:
- Zoster incidence was 0.552 cases per 100 person-years in vaccinated children (n=346).
- In matched pairs, zoster incidence was 1.23 cases per 100 person-years in vaccinated children (n=84) versus 3.11 cases per 100 person-years in naturally infected children (n=84).
- Leukemia recurrence was associated with higher zoster risk (P < 0.025); zoster was not a marker for relapse.
Conclusions:
- The incidence of zoster following live attenuated varicella vaccine immunization is not greater than that following natural varicella infection in children with ALL.
- Varicella vaccination appears safe and effective in reducing zoster incidence in this population.
- Zoster in ALL patients does not predict leukemia relapse.
Abstract:
We examined the incidence of zoster in 346 children with underlying acute lymphoblastic leukemia who were immunized with live attenuated varicella vaccine while in remission. We also compared a subset of 84 of these children with a matched group of 84 children with leukemia who had had natural infection with varicella. Of the 346 vaccinated children, 5 (1.45 percent) became infected with zoster after 10,878 months of observation, for an incidence of 0.552 case per 100 person-years. Among the matched pairs of subjects, zoster occurred in 3 (3.6 percent) of the 84 vaccinated subjects during 2936 months of observation--an incidence of 1.23 cases per 100 person-years--and in 11 (13.1 percent) of the subjects with natural infection during 4245 months--an incidence of 3.11 cases of zoster per 100 person-years. Although the incidence of zoster was more than twice as high in the control children as in the vaccinated children (3.11 vs. 1.23 cases per 100 person-years), a Kaplan-Meier product-limit analysis revealed no significant differences in incidence between the two groups. Children from both groups in whom leukemia recurred were more likely to contract zoster than those who did not have a recurrence (7 of 35 vs. 7 of 133, P less than 0.025). Zoster was not a marker for impending relapse. No case of zoster was severe or disseminated. We conclude that the incidence of zoster following immunization with live attenuated varicella vaccine is no greater than that following natural varicella infection.