Field Trial of a Vaccine against New World Cutaneous Leishmaniasis in an At‐Risk Child Population: Safety, Immunogenicity, and Efficacy during the First 12 Months of Follow‐Up

Abstract

The safety, immunogenicity, and efficacy of a vaccine against cutaneous leishmaniasis in rural Ecuadorian children was assessed in a randomized, controlled, double-blinded study. Vaccine group subjects received 2 intradermal doses of a whole, killed promastigote vaccine cocktail plus bacille Calmette-Guérin (BCG) adjuvant. Control subjects got 2 doses of BCG only. The subjects who received both vaccination doses, 438 in the vaccine group (79.3%) and 406 in the control group (83.4%), were followed for 12 months. No serious adverse side effects were identified in either group. Significantly more vaccine group subjects than controls converted to a positive Montenegro skin test (85.1% vs. 20.1%; chi2 = 279; P < .001). The incidence of cutaneous leishmaniasis was significantly reduced in the vaccine compared with the control group (2.1% vs. 7.6%; chi2 = 8.95; P < .003). The protective efficacy of the vaccine was 72.9% (95% confidence interval = 36.1%-88.5%).

Comparative evaluation of phenol and thimerosal as preservatives for a candidate vaccine against American cutaneous leishmaniasis

“…The data obtained from this experiment, combined with the significant increase in the antigen-stimulated spleen cell proliferative response after vaccination demonstrate the immunogenic efficacy of the single strain candidate vaccine. The current results confirm those conducted by other groups working with candidate vaccines formulated with different Leishmania strains that showing the immunogenicity of the candidate vaccine is maintained with both merthiolate and phenolate preservatives (Mayrink et al 1979, Mendonça et al 1995, Armijos et al 1998, 2004.…”

Immunogenicity in dogs of three recombinant antigens (TSA, LeIF and LmSTI1) potential vaccine candidates for canine visceral leishmaniasis

“…Extensive vaccination trials in Brazil and Ecuador against cutaneous leishmaniasis in humans have demonstrated that a cocktail of five killed Leishmania stocks or a single strain of L. amazonensis induces protection from natural infection [1,13,23,32]. However, to date, the protection efficacy of these or other vaccines in dogs against visceral leishmaniasis is highly controversial [15,28,33,34].…”

Epidemiology of leishmaniasis in Ecuador: current status of knowledge - A review

“…A vaccination trial with killed cocktail of promastigotes was conducted in the subtropical-Ecuador (Armijos et al 1998) showing significant protection during the first 12 months (72.9%). Protection declined until month 60 of follow-up, with no difference in protection rate between the vaccinated and placebo groups (Armijos et al 2003).…”