Abstract
We report 2 children with life-threatening breakthrough varicella. Both had received 1 varicella vaccination before onset of cancer. Despite treatment with intravenous acyclovir, 1 child died of disseminated varicella. Because similar fatal cases have been reported, high-risk immunocompromised children with 1 varicella vaccination may warrant the same varicella prophylaxis as immunocompromised children who have never been vaccinated.