Early measles vaccination in bone marrow transplant recipients

Measles vaccination has been recommended after the second year following bone marrow transplant ( BMT) in patients not receiving immunosuppressive drugs. During a measles outbreak, we vaccinated all patients after the first year of transplant, and conducted a prospective trial to evaluate safety, effectiveness and sustained immunity after early vaccination. Patients received attenuated virus vaccine between 9 and 18 months after BMT. A total of 51 patients were evaluated and 27 of them ( 52.9%) were receiving immunosuppressive drugs. Only mild adverse reactions were noted. Nine patients ( 17.6%) were susceptible ( IgG <= 100 mIU/ ml) at vaccination, and all seroconverted. In those immune at vaccination, a four- fold increase in measles IgG titers was found in one of 34 patients ( 2.9%) with specific IgG >= 200mIU/ ml compared to 14 of 17 ( 82.3%) with IgG < 200 mIU/ ml ( P < 0.0001). Sustained immunity after 24 months was more likely to occur in patients with specific IgG levels <= 200 or >= 500 mIU/ mL ( 83.4 and 100%, respectively) in comparison to patients with 200 < IgG < 499 mIU/ ml at vaccination ( 50%; P = 0.017). We conclude that even though early measles vaccination is safe, few patients are susceptible on day + 365 and this strategy should be reserved for epidemic situations posing significant threat for the patients.