Polio doctors commemorated
The US Postal Service have issued new stamps to honor two of America's most esteemed scientists, Dr Jonas Salk and Dr Albert Sabin.
The two were instrumental in developing vaccines for paralytic poliomyelitis, or 'polio' as it is better known, as well as a number of other infectious diseases. Both men have now been honored as part of the Distinguished Americans series of stamps.
Salk is depicted on the 63-cent stamp, the rate for two-ounce First-Class mail, and Sabin on the 87-cent stamp, the three-ounce First-Class rate.