Reactional states and neuritis in multibacillary leprosy patients following MDT with/without immunotherapy with Mycobacterium w antileprosy vaccine

A vaccine based on autoclaved Mycobacterium w was administered, in addition to standard multidrug therapy (MDT), to 157 untreated, bacteriologically p ositive, lepromin negative multibacillary leprosy patients, supported by a well matched control group of 147 patients with similar type of disease, wh o received a placebo injection in addition to MDT. The MDT was given for a minimum period of 2 years and continued until skin smear negativity, while the vaccine/placebo was given at 3-monthly intervals up to a maximum of eig ht doses. The incidence of type 2 reaction and neuritis during treatment an d follow-up showed no statistically significant difference in the vaccine a nd placebo groups. The incidence of type 1 reaction (mild in most cases), h owever, was higher in the vaccine group (P = 0.041, relative risk ratio 1.7 9), considering LL, BL and BE leprosy types together, and considerably high er (P = 0.009) in LL type, probably because of confounding due to higher nu mber of patients with previous history of reaction in this group. The occur rence of reactions and neuritis in terms of single or multiple episodes was similar in the vaccine and placebo groups. The association of neuritis and reactions, as well as their timing of occurrence (during MDT or follow-up) , was also similar in the two groups, with more than 90% of occurrences tak ing place during MDT. The incidence of reversal reaction was significantly higher among the males in the vaccine group (34.5% versus 8.3%, P = 0.019). Patients with high initial BI (4.1-6.0) showed higher incidence of reactio ns (70.3%) as compared to those with medium (2.1-4.0) and low (0.3-2.0) BI where the reactions were observed with a frequency of 56.1% and 38.8%, resp ectively. However, unlike reactions, neuritis incidence did not seem to be affected by initial BI to the same extent in the vaccine group, with freque ncies of 35.3%. 36.3% and 25.9% in the three mentioned BI ranges. Overall, the vaccine did not precipitate reactional states and neuritis over and abo ve that observed with MDT alone.