Mycobacterium w vaccine, a useful adjuvant to multidrug therapy in multibacillary leprosy: a report on hospital based immunotherapeutic clinical trials with a follow-up of 1-7 years after treatment
P. Sharma et al., Mycobacterium w vaccine, a useful adjuvant to multidrug therapy in multibacillary leprosy: a report on hospital based immunotherapeutic clinical trials with a follow-up of 1-7 years after treatment, LEPROSY REV, 71(2), 2000, pp. 179-192
A vaccine based on autoclaved Mycobacterium w was administered, in addition
to standard multidrug therapy (MDT), to 156 bacteriologically positive, le
promin negative multibacillary leprosy patients compared to a well matched
control group of 145 patients with a similar type of disease who received a
placebo injection in addition to MDT. The MDT was given for a minimum peri
od of 2 years and continued until skin smear negativity, while the vaccine
was given at 3-month intervals up to a maximum of eight doses. The fall in
clinical scores and bacteriological indices was significantly more rapid in
vaccinated patients, from 6 months onward until years 2 or 3 of therapy. H
owever, no difference was observed in the fall in bacteriological index in
the two groups from year 4 onwards. The number of LL and BL patients releas
ed from therapy (RFT) following attainment of skin smear negativity, after
24-29 months of treatment was 84/133 (63.1%) in vaccinated and 30/120 (25.0
%) in the placebo group; the difference was highly statistically significan
t (P < 0.0001). In all, 90.2% patients (146/162) converted from lepromin ne
gativity to positivity in the vaccine group, as against 37.9% (56/148) in t
he placebo group. The average duration of lepromin positivity maintained fo
llowing eight doses of vaccine administered over 2 years was 3.016 years in
the vaccine and 0.920 years in the placebo group. Histological upgrading a
fter 2 years of treatment in the LL type was observed in 34/84 (40.5%) case
s in the vaccine and 5/85 (5.9%) cases in the placebo group, the difference
being statistically significant (P < 0.001). The incidence of type 1 react
ions was significantly higher (30.5%) in the vaccine group than (19.7%) in
the placebo group (P = 0.0413); the difference was mainly observed in LL ty
pe (P = 0.009). The incidence of type 2 reactions was similar (31.8 and 34.
6%) in vaccine and placebo groups. The vaccine did not precipitate neuritis
or impairments over and above that encountered with MDT alone. After 5 yea
rs of follow-up following RFT, no incidence of bacteriological or clinical
relapses was observed in both groups.