How Long Does Butter Last? How long does butter last? Butter lasts for about 6-9 months in the refrigerator and if there is a best by date stamped on the package then it will last for at least a month beyond that date, that is if it has been stored properly.
Jonas Salk is credited with developing the first polio vaccine in 1955, an injected vaccine containing killed virus, but the oral live vaccine devised a little later by his competitor Albert Sabin is the workhorse of the Global Polio Eradication Initiative.onas Salk is credited with developing the first polio vaccine in 1955, an injected vaccine containing killed virus, but the oral live vaccine devised a little later by his competitor Albert Sabin is the workhorse of the Global Polio Eradication Initiative.
Even before another successful vaccine was discovered, Dr. Salk's discovery had reduced polio and its effects by 97 percent. Today, polio is not a familiar disease to younger Americans, and many have difficulty appreciating the magnitude of the disorder that the Salk vaccine virtually wiped from the face of the Earth.onas Edward Salk (/sÉËlk/ ; October 28, 1914 â June 23, 1995) was an American medical researcher and virologist. He discovered and developed the first successful polio vaccine.