Primary Outcome Measures:
- Frequency of vaccine-related reactogenicity events and other adverse events [ Time Frame: Throughout study ] [ Designated as safety issue: Yes ]
- Amount of vaccine virus shed by each participant [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
- Amount of serum and nasal wash antibody induced by the vaccine [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
Secondary Outcome Measures:
- Number of participants infected with the H2N2 1960 AA ca recombinant vaccine [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
- Phenotypic stability of vaccine virus shed [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
- Determine whether immunogenicity is enhanced by a second dose of vaccine, and whether the first dose of vaccine restricts replication of the second dose [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
- T-cell mediated and innate immune responses against the H2N2 1960 AA ca recombinant vaccine [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
H2N2 influenza viruses emerged in the 1950s replacing the then circulating H1N1 human influenza virus. The first cases occurred in China in 1956, and disease became widespread in 1956-1957, resulting in the "Asian Influenza" pandemic that was responsible for between 1 and 4 million deaths worldwide. H2N2 viruses have not circulated since 1968, when they were replaced by H3N2 influenza viruses and the resurgence of H1N1 viruses. For this reason, a large proportion of the population is now susceptible to infection with H2N2 influenza. If this subtype re-emerges, it could potentially cause the next pandemic. This vaccine, therefore, is an important priority in the development of vaccines against potential pandemic influenza strains.
This vaccine trial will be conducted in the Center for Immunization Research isolation unit in the Mason F. Lord Building at the Johns Hopkins Bayview Medical Center (Baltimore, MD). The study will be initiated between April 1st and December 20th, 2008, when wild-type influenza is unlikely to be circulating in the Baltimore area.
An individual's participation in the study will last approximately 90 days. All participants will receive two vaccinations approximately 4 - 8 weeks apart. After each vaccination, participants will remain in isolation at the study site for at least nine days or until rRT-PCR assays for influenza are negative for 2 consecutive days. A physical examination and nasal wash will occur each day during the isolation period. Blood collection will occur in isolation beginning on Day 7 until release. Follow-up outpatient visits are scheduled on Days 28 and 56 after the first vaccination and on Day 28 after the second vaccination. Follow-up visits will include serum collection, nasal wash, and interim medical history.