Smallpox vaccine get to a populated place. The world health system is completely unprepared for this." In the United Kingdom, controversy occurred regarding the company which had been contracted to supply the vaccine. This was because of the political connections of its owner, Paul Drayson, and questions over the choice of vaccine strain. The strain was different from that used in the United States. Plans for mass vaccinations in the United States stalled as the necessity of the inoculation came into question. Smallpox vaccine Smallpox vaccine, the first successful vaccine to be developed, was introduced by Edward Jenner in 1796. He followed
Usable fuel Usable fuel In aviation, usable fuel is the fuel on board an aircraft that can actually be used by its engines. The opposite of usable fuel is unusable fuel. The unusable fuel figure is calculated for an aircraft fuel tank in "the most adverse fuel feed condition occurring under each intended operation and flight maneuver involving that tank". The figure usable fuel is used when calculating or defining other key figures of an aircraft such as MTOW, zero-fuel weight etc. Usable fuel is the total amount of fuel in an aircraft minus the fuel that cannot be fed into the