Influenza A viruses are widely found in nature and can infect a wide variety of birds and mammals, including humans. Some types of influenza A viruses are more likely to spread from animals to humans, and researchers are interested in monitoring these viruses and developing potential vaccines for them. H7N7 is one type of influenza A virus. In recent years, there have been several H7N7 outbreaks among humans, and the development of an H7N7 vaccine is a high priority. This study will enroll two groups of participants: people who have previously received one of three types of a pandemic LAIV as part of a research study and people who have not previously received a LAIV vaccine. The purpose of this study is to evaluate the safety and immunogenicity of a single dose of an inactivated H7N7 vaccine in these two groups of participants.