To gauge the effectiveness of the strategy, U.S .researchers, led by a doctor who helped initiate the program, analyzed online donor registration activity and saw a 21-fold boost across the U.S. in a single day after the launch.
 

Facebook launched the program in the U.S., the U.K., and Australia, then subsequently in 17 countries around the globe. Currently there is a rollout schedule to include the rest of the world, lead researcher Andrew M. Cameron, M.D., an associate professor of surgery at Johns Hopkins University School of Medicine, said.
 

Dr. Cameron and his team found that in the weeks after the Facebook initiative launched, there was a significant spike in donor registration in all states in the US. On the first day of the launch, there were 13,054 new online registrations. Nearly seven times as many people registered on the first day of the Facebook initiative in Michigan, and Georgia saw a 109-fold increase. The states of New York and Texas, where organ donation rates are among the lowest, also had some of the biggest bumps on that first day.
 

The findings were published in the American Journal of Transplantation.
 

"The short-term response was incredibly dramatic, unlike anything we had ever seen before in campaigns to increase the organ donation rate," said Dr. Cameron. "And at the end of two weeks, the number of new organ donors was still climbing at twice the normal rate.
 

"If we can harness that excitement in the long term, then we can really start to move the needle on the big picture. The need for donor organs vastly outpaces the available supply and this could be a way to change that equation."
 

Over the last two decades, despite many efforts, the number of donors in the US has remained relatively static, while the number of people waiting for transplants has increased 10-fold, the researchers said. There are more than 118,000 people currently on waiting lists in the U.S. for kidneys, livers and other organs. It is believed that over time, roughly 100 million Americans have registered to donate.
 

Dr. Cameron, a transplant surgeon, says that the Facebook initiative came about through conversations with Harvard University classmate — and current Facebook chief operating officer — Sheryl Sandberg at their 20th university reunion in 2011.
 

He added that he has spoken to Facebook officials who are discussing launching the initiative on its mobile platform, changing its prominence on the Web version or even offering incentives, such as coupons, for people who declare they are organ donors.
 

"This was the first effort like this designed to mobilize people for a public health cause," he said. "Now we want to build on that. Studying the response to the organ donor effort is the next step in the process of using social media for social good."
 

In a single day, Johns Hopkins researchers found, suggesting social media might be an effective tool to address the stubborn organ shortage in the United States.