Phase I Trial of Smallpox Vaccine

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

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.

About this trial record page

What this page shows

Public field values for ClinicalTrials.gov record NCT00046397, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.

What this page does not do

No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.

Where the data comes from

Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.

Last refresh

Last update posted Mar 3, 2008 · Synced Sep 9, 2026

Related: full search, browse by condition, browse by drug or therapy, browse by sponsor, browse by U.S. city.