[nostrademons]

"Most contagious" is accurate.

"Most lethal" is accurate if you're talking total deaths, not death rate, and if you assume the non-existence of vaccines. Pre-vaccination, roughly 7-8m children died every year from measles. By comparison, HIV currently kills about 1.1m, TB kills 1.5m, and malaria kills about 438k. This is an admittedly misleading definition of "most lethal", though, because it incorporates its contagiousness as a factor and assumes no vaccines and developing-world conditions. In the developed world, the death rate from measles is only about 0.2%, which is comparable with some of the more virulent influenza strains, but still an order of magnitude less than the 1918 flu pandemic.