With a doodle heading its search home page, Google is celebrating the development of the polio vaccine by Jonas Salk on the 100th anniversary of his birth.

Salk's vaccine, declared effective and safe in 1955 and launched in a mass vaccination campaign in the United States, virtually eradicated polio in this country from that time to the present.

"In the two years before [the] vaccine was widely available, the average number of polio cases in the U.S. was more than 45,000," the Salk Institute in La Jolla, Calif., says. "By 1962, that number had dropped to 910."

In the 21st century, there have been just two cases reported in the United Sates, and one of them was acquired overseas.

Famously, Salk chose not to pursue a patent for his vaccine. On the day it was declared as safe for widespread use, he said in an interview with renowned journalist Edward R. Murrow, "There is no patent. Could you patent the sun?"

Although seen as a noble act on the part of Salk, the truth is a bit more complex.

Much of the original research had been done at the University of Pittsburgh with funding from the National Foundation for Infantile Paralysis, both of which investigated the possibility of applying for a patent.

Salk dissuaded them by explaining that the techniques he used in creating the vaccine weren't all that new and that his research was based on many years of prior work by other scientists.

Still, his research went against current thinking that an effective vaccine could only be created using live viruses. Salk pursued a  "killed-virus" vaccine by growing samples of the polio virus and then adding formaldehyde so that they could no longer reproduce.

The "killed-virus" vaccine, when injected into the bloodstream, caused the body's immune system to create protective antibodies without the risk of introducing a weakened but living form of the virus into healthy patients.

Salk, born in 1914 in New York, received his M.D. degree in 1939 from the New York University School of Medicine.

At the University of Michigan, he worked on developing an influenza vaccine, then became the director of the Virus Research Laboratory at the University of Pittsburgh School of Medicine.

It was there that he began to work on the research techniques that would lead to the development of his polio vaccine.

In the 1960s he created the Salk Institute in California for research into multiple sclerosis, cancer immunology and autoimmune diseases. The work there included development of an AIDS vaccine.

Salk died in 1995 at his home in La Jolla at age 80.