The findings, reported in the January issue of Pediatric Nephrology, are critical for chronic kidney disease patients, particularly children who will eventually undergo a kidney transplant. After transplantation, immunosuppressive medications put these children at high risk for severe chicken pox complications, including pneumonia, brain inflammation, and death.
"We recommend pediatric nephrologists include chicken pox vaccination as an important component of pre-end-stage renal disease and end-stage renal disease care," said the study's lead author, Susan L. Furth, M.D, Ph.D., a pediatric nephrologist at the Children's Center.
Varicella vaccine contains small doses of weakened strains of the chicken pox virus that activate immune system "memory" and mount a protective response to subsequent exposures.
In healthy children under 12 years of age, vaccination in a single dose is recommended, while two doses are recommended for adolescents. Without vaccination, infections in children whose immune systems have been weakened by a genetic disorder, disease, or medical treatment can cause serious complications.
In a multi-center, prospective, three-year clinical trial, Hopkins researchers, with the cooperation of the Southwest Pediatric Nephrology Study Group, identified 96 children with chronic kidney disease with no history of chicken pox. About half of these patients did not have detectable varicella antibodies. Each child received two injections of varicella vaccine, rather than the one dose typically given to healthy children. The doses were administered four to eight weeks apart.
One child developed chicken pox following a known exposure. There were no reported serious side effects following vaccination. Eleven patients developed a rash associated with the vaccine, and seven patients reported mild to moderate redness or soreness at the site of injection.
Over three years of follow-up, researchers report each child – including 16 children who received kidney transplants following vaccination – maintained the varicella antibody, and 87 percent retained antibody levels for more than three years. Although kidney transplant recipients tended to have lower varicella antibody levels during the first two years of follow-up, researchers report that antibody levels increased over time.
Children's Center pediatric nephrologist Barbara A. Fivush, M.D., and researchers from the Johns Hopkins Bloomberg School of Public Health, Columbia Hospital at Medical City, and Merck & Co. contributed to the report. The study was funded by a grant from Merck & Co.
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Pediatric Nephrology