Infections of the respiratory and gastrointestinal tracts are among the most common diseases of piglets worldwide and can cause large amounts of economic loss to swine producers. Vaccine formation and delivery to the areas targeted by the disease is still difficult to do. Delivery of vaccines orally or intra-nasally has the benefit of stimulating immunity on the mucus surfaces without the hazards of using a needle. This has been proven to increase the immunity directly at the site of infection. Modified live vaccines are dangerous because the pathogen can mutate back to an infectious state. There is work being done on alternate methods of vaccination. Improved technologies to deliver vaccines to the target location are important for both killed and live vaccines, and most of these are still in development.