Varicella and zoster in children after kidney transplantation: long-term results of vaccination.

OBJECTIVE

To determine the long-term prevalence of varicella infection and herpes zoster after kidney transplantation and to assess the effectiveness of varicella immunization with the Oka attenuated strain.

METHODS

This study involved 704 children and adolescents who received a kidney graft in our institution from 1973 to 1994 and had routinely been given varicella vaccine beginning in 1980 in preparation for transplantation.

RESULTS

After vaccination 62% of these patients still had varicella/zoster (VZ) antibodies at 1 year and 42% after 10 years. After transplantation the incidence of varicella was significantly lower, 26/212 (12%), in patients who received immunization than in those who did not and had no history of varicella, 22/49 (45%). The disease was also significantly less severe in the vaccinated patients (three deaths among naive patients vs none among vacciness). In the vaccinees, varicella infection was observed only in those who did not develop or lost VZ antibodies; in addition, 21 patients of this subgroup had an asymptomatic seroconversion. Four of the 415 patients with a history of varicella had another episode of benign varicella after grafting. Herpes zoster was observed in 76 of the 704 patients included in the study. The prevalence differed according to VZ status at the time of grafting: 13% in patients with a history of varicella, 7% in the vacciness, and 38% in the naive patients at grafting who developed varicella. Three rejection episodes occurred in association with a varicella episode and four with a zoster episode, but graft function was only transiently impaired, and as a whole varicella or zoster did not significantly affect graft function or survival.

CONCLUSION

Naive VZ patients with a kidney graft are at risk to develop severe varicella and this may be effectively prevented by available immunization.