The mean yearly registered nurse salary in Pennsylvania was $66,010 which was equivalent to $31.74 mean hourly wage. The median per hour wage amounted to $31.17. The average RN salary in PA was $64,000 as stated by indeed.com.
Two polio vaccines are used throughout the world to provide immunity to the virus that causes poliomyelitis (or polio). The first was developed by Jonas Salk through the use of HeLa cells and first tested in 1952.Announced to the world by Dr Thomas Francis Jr. on 12 April 1955, it consists of an injected dose of inactivated (dead) poliovirus. An oral vaccine was developed by Albert Sabin using attenuated or weakened poliovirus.he two vaccines have eliminated polio from most countries in the world, and reduced the worldwide incidence from an estimated 350,000 cases in 1988 to just 223 cases in 2012. In November 2013, the World Health Organization announced a polio outbreak in Syria.
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.ntil 1957, when the Salk vaccine was introduced, polio was considered one of the most frightening public health problems in the world. In the postwar United States, annual epidemics were increasingly devastating.