Improving Polio Vaccine

Polio is a serious disease that can cause paralysis and death. It is caused by a virus and can be prevented by vaccine. The World Health Organization's (WHO) Global Polio Eradication Initiative is trying to get rid of all polio disease around the world. Researchers want to help by testing a new vaccine. In many countries, people are vaccinated with oral polio vaccine (OPV) given by mouth during childhood. OPV is good at giving immunity (protection from polio) in the body and the gastrointestinal (GI) tract. Immunity in the GI tract is called mucosal immunity. The downsides of using OPV are that it can be shed into the environment in people's feces after vaccination where it can infect people who are not vaccinated, and it can cause paralysis in 2-4 of every one million children vaccinated with OPV. The United States (U.S.) stopped giving any OPV to people for vaccinations in the 1990's. Since then, a polio vaccine called inactivated polio vaccine (IPV) is given as an injection for routine childhood immunizations in the U.S. You cannot get polio infection from IPV and it will not be shed into the environment. In 2016, the WHO started a plan to help other countries gradually get rid of OPV. The downside of using IPV by itself is that, unlike OPV, it doesn't give enough mucosal immunity to protect people living in places where there is still polio. There are also supply shortages of IPV, which is a problem if there are outbreaks of polio. For the supply of IPV to help more people, it is safe and effective to use a tiny dose of IPV injected under the top layer of skin (intradermal or ID injection) rather than getting the full dose in the muscle. This is called a fractional dose of IPV, or fIPV. To help stop using OPV globally, a better fIPV vaccine is needed. fIPV vaccine needs a substance to help stimulate a mucosal immune response. dmLT is a substance that has been shown to stimulate a mucosal immune response. It has been shown to be safe and effective in both humans and animals, both by itself and when given with other vaccines. This study will test a mixture of fIPV-dmLT given intradermally (under the outer layer of the skin). This is the first study done in humans to give this combination intradermally. The IPV vaccine has already been approved by the FDA. The fIPV-dmLT vaccine has not been approved by the FDA.