The World Health Organization recently called for the worldwide use of needle syringes that self-destruct after a single injection.
These “smart” syringes are a response to a problem that medical authorities have recognized for decades — the frequent reuse of disposable shots. An estimated 25 percent of the 18 billion medical injections performed worldwide each year are done with dirty needles. Unsafe injections cause as many as 1.7 million new hepatitis B infections annually, 315,000 hepatitis C infections and 33,800 HIV infections, according to the World Health Organization. Stopping these infections would be a boon for public health.
“This is a risk we don’t have to be taking,” the WHO’s Lisa Hedman said.
But changing the practice – especially in poor countries – has proven difficult. In some places, syringes are scarce. Or the dangers are not fully appreciated, despite education campaigns. And sometimes health-care providers can just get lazy.
So how do you stop people from reusing syringes?
How do you remove the temptation?
The WHO has been hunting for solutions for nearly 25 years. Only recently has the technology become feasible – cheap, easy to use, hard to break – for an announcement like the WHO made Monday.
“It’s not simple,” WHO spokeswoman Judith Mandelbaum-Schmid said. “There had to be quite a lot of engineering.”
The WHO’s quest began in 1987 – just as the spread of a disease called HIV was beginning to cause alarm. At the same time, the widespread switch from glass syringe tubes to plastic ones made reuse even more risky, since glass containers could be disinfected with heat, while plastic melted and warped.
The agency put out a call for syringe designs that automatically and irrevocably stopping working after a single filling and injection. The syringes essentially needed to break after one use.
The WHO wanted to use these shots to deliver vaccines.
One place that took up the challenge was Path, a small international health technology company in Seattle. Staff already had begun playing around with different designs two years earlier. They knew they had to make their invention work with existing plastic syringes to keep costs down, said Steve Brooke, the company’s commercialization adviser.
There were examples out there. Patents for single-use syringes dated back to 1960s. But none seemed to fit the need.
Path came up with a plastic syringe with a metal clip inside it that locked into place after the plunger was depressed. A syringe manufacturer licensed the product.
In 1990, the Soloshot hit the market. Since then, it has been used to deliver more than 6 billion vaccine shots.
But the Soloshot was limited to the vaccination market, which accounts for only 5 to 10 percent of all injections worldwide. The product didn’t work in syringes with varying dosages, where the plunger is pulled back to different levels.
“People started to realize, what about the other 90 percent?” said Hedman, who is the WHO’s technical officer for essential medicines and health products.
Solving that problem would take several more years.
The effort received an unexpected boost in 2000 when the U.S. Congress passed the Needlestick Safety and Prevention Act, which required steps to reduce the risk of health-care workers accidentally stabbing themselves with needles.
That led to inventions such as the spring-loaded needle, which retracts after use “like a ballpoint pen,” Hedman said. And there are syringes with plastic covers that can be slipped over a needle and locked into place.
Although these devices were designed to protect nurses and doctors, they also rendered the syringes inoperative after a single use.
Other designs came on the market. A man named Marc Koska developed the K-1 syringe, with a plunger that breaks off if you try to reload it. He’s delivered TED talks about the experience.
Today, there are more than 70 suppliers of non-reusable syringes.
“But it took a long time for industry to respond,” Hedman said.
The WHO’s call to use self-destructing syringes is seen as a step to pushing for the widespread adoption of the devices. The technology works and is priced on par with regular syringes. The need is greatest in the developing world. But the reuse of syringes remains enough of a problem in the United States that the U.S. Centers for Disease Control and Prevention runs a One & Only campaign to reinforce the message.
Unsafe medical injections have affected at least 150,000 U.S. patients since 2001, according to the CDC.
Preventing these exposures is as simple as a tiny flange that stops a syringe from being reloaded “like going the wrong way out of a rental car parking lot,” Hedman said.
She appreciated the simplicity of some of these solutions.
“They are elegant little things,” she said.
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