Clinical Trial: Prevalence of Hookworm Infection and Community Preparedness for Hookworm Vaccine Trials in Endemic Areas of Brazil

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Determination of Prevalence and Intensity of Hookworm Infection and Community Preparedness for Hookworm Vaccine Trials in Endemic Areas of Northeastern Minas Gerais, Brazi

Brief Summary: Na-ASP-2 is a protein expressed during the larval stage of the N. americanus hookworm life cycle. In a clinical study in previously hookworm-infected adults in Brazil, this protein induced urticarial reactions (rash) in a subset of volunteers. The clinical trial component of this study involves skin testing for immediate-type hypersensitivity to the Na-ASP-2 Antigen. Both prick-puncture and intradermal tests will be applied.

Detailed Summary:

The clinical testing of the Na-ASP-2 Skin Test Reagent to detect Immediate-type hypersensitivity to the Na-ASP-2 hookworm antigen will be conducted as part of a larger, on-going observational study of the prevalence and intensity of hookworm infection currently underway in Brazil. Eligible adult participants (ages 18-45 years) in this observational study will be invited to undergo the skin testing procedure. Skin testing will only be performed if they agree and sign the supplemental informed consent form for this skin testing procedure.

  • Study site: Americaninhas Vaccine Center, Americaninhas, Minas Gerais, Brazil
  • Number of participants to be skin tested: approximately 150 adults
  • Duration of the skin testing procedures: up to 1 month; each participant will undergo skin testing and a follow-up blood collection 21+/-7 days after skin testing.

  • Each participant will have both skin prick-puncture and intradermal skin tests applied on the same study day. The prick-puncture and intradermal tests will be applied sequentially to the volar aspects of the participant's forearms:

    1. Skin prick-puncture: three different concentrations of Na-ASP-2 solution (10, 100, and 1000 μg/mL) will be applied sequentially in duplicate, to the left forearm.
    2. Intradermal: one concentration of Na-ASP-2 (100 μg/mL) will be injected, in duplicate, to the right forearm.
    3. Allergen diluent and histamine solutions will be utilized as the negative and positive controls, respectively, for both the skin prick-puncture and intradermal tests.

    4. Sponsor: Albert B. Sabin Vaccine Institute

      Current Primary Outcome: Size of wheal diameter at site of skin test application, measured 15 minutes after injection [ Time Frame: 15 minutes after skin test application ]

      Original Primary Outcome: Same as current

      Current Secondary Outcome: Anti-Na-ASP-2 IgE antibody level on day of skin test reaction [ Time Frame: Upon skin testing ]

      Original Secondary Outcome: Same as current

      Information By: Albert B. Sabin Vaccine Institute

      Dates:
      Date Received: July 13, 2009
      Date Started: August 2009
      Date Completion:
      Last Updated: January 6, 2014
      Last Verified: January 2014