This study will test the safety of an experimental vaccine called Modified Vaccinia Virus
Ankara (MVA) for use against the smallpox virus. It will also investigate how many injections
of MVA are needed to produce immunity against vaccinia virus, which is closely related to the
smallpox virus. An effective smallpox vaccine exists, but it can cause side effects that, on
rare occasions, can be life-threatening. The FDA gave new license approval for Dryvax on
10/25/02, but has not been used in the general population since smallpox was eradicated
worldwide. Both the MVA and Dryvax® (Registered Trademark) vaccines are made using the
vaccinia virus, however the MVA vaccine contains a more attenuated, or weakened, form of the
virus. [http://www.fda.gov/cber/products/smalwye102502.htm]
Healthy normal volunteers between 18 and 30 years of age, who have never been vaccinated with
a smallpox vaccine, may be eligible for this study. Candidates will be screened with a
medical history, physical examination, and blood and urine tests, including an HIV test and a
pregnancy test for women of childbearing potential.
MVA, placebo and Dryvax® (Registered Trademark) will be administered by different methods.
The MVA vaccine and placebo are injected into an arm muscle with a needle and syringe. The
Dryvax® (Registered Trademark) vaccine is administered, as it was for many years, with a
special forked needle that is poked lightly into the skin of the upper arm, usually 15 times,
in a process called scarification. When the vaccine works, a small pus-filled blister forms,
followed by a scab and then scarring at the site of the vaccination. The formation of the
blister and scab is called a take, indicating that the vaccine is effective and is evidence
of the development of immunity. The development of a take suggests that an individual will be
protected against smallpox for at least a few years. If scarification does not take, it can
either mean that the person already has immunity or that the vaccine did not work.
Participants will be assigned to groups, as well as, product randomly. For instance, the
first study participant could be enrolled into group 3. The Dryvax® (Registered Trademark)
dose is given as a challenge to see if the person has a take. A reduced take response or no
take, could suggest that MVA is able to produce an immune response. The dosing schedules vary
from 12 to 24 weeks and volunteers are in the study a total of 24 to 36 weeks, depending on
the number of injections.
Participants will be observed for at least 1 hour after each injection. They will come to the
clinic a week after MVA or placebo injections and at least twice a week after Dryvax®
(Registered Trademark) for about 21 days to have the injection site evaluated and
photographed. At each visit, participants will be asked about how they are feeling and if
they are taking any medications. Blood and urine tests will be done on injection days and at
follow up visits scheduled 1 and 4 weeks after each immunization as well as 12 weeks after
the Dryvax® (Registered Trademark) challenge dose. Additional tests may be done between
visits if medically necessary.
Phase:
Phase 1
Details
Lead Sponsor:
National Institute of Allergy and Infectious Diseases (NIAID)