You might not want to hear this, but there's a good reason to be scared of needles: the most deadly clinical procedure in the world is a simple injection.

Every year, 1.3 million deaths are caused by unsafe injections, due to the reuse of syringes. The World Health Organisation (WHO) estimates that up to 40% of the 40bn injections administered annually are delivered with syringes that have been reused without sterilisation, causing over 30% of hepatitis B and C cases and 5% of HIV cases – statistics that have put the problem at number five on the WHO priority list.

It is a call to arms that stirred Dr David Swann, reader in design at the University of Huddersfield, into action, to develop what he describes as a "behaviour-changing syringe" that would warn patients when the needle was unsafe – a design that is now in the running for the Index design awards.

"The difficulty for patients is that it is impossible to determine a visual difference between a used syringe that has been washed and a sterile syringe removed from its packaging," says Swann. "Instigating a colour change would explicitly expose the risk and could indicate prior use without doubt."

Keen to keep the price down to ensure accessibility, Swann turned to cheap technologies used in the food industry, using inks that react to carbon dioxide and packaging the syringes in nitrogen-filled packets – just the same as a bag of crisps. Once opened and exposed to the air, the syringe has a 60-second treatment window before turning bright red, while a faceted barrel design means that the piston will break if someone tries to replace it. Remarkably, the ABCs (A Behaviour Changing Syringe) cost only 0.16p more than a typical 2.5p disposable syringe.

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Swann is trialling the product in India, as the country is the largest consumer of syringes in the world, accounting for 83% of all injections – over 60% of which are deemed unsafe, and 30% of which transmit a disease in some form, according to the WHO.

"There are landfill scavengers searching piles of waste for syringe devices that are then sold on to medical establishments," says Swann. "We want to break that cycle." He estimates that after five years, the ABCs will have prevented 700,000 unsafe injections, saved 6.5 million life years and saved $130m in medical costs in India alone.

Colour-changing technology is increasingly finding medical applications, as designers look to transfer innovations in reactive ink towards potentially lifesaving ends. Husband and wife doctor/designer duo Gautam and Kanupriya Goel have developed a form of packaging for medicine that gradually changes its pattern as the product expires.

Now you see it … colour-changing packaging warns when the medicine has expired. Photograph: Gautam and Kanupriya Goel

"Outside of the west, there is little awareness of the concept of a medicine becoming expired," say the Goels. "We're not even just talking about the market shelf-life of a medicine strip here. It's alarming how little the average person understands how quickly a medicine becomes dangerous for consumption."

Their solution uses a packing material that visually "self-expires" over a designated time period. It is composed of two layers of information – the foreground, which shows the medicine label, and the background, which displays a warning expiration message – that are separated by multiple sheets of diffusible material. As time passes, the ink from the background layer will seep through to display the warning symbols, designed as universally understood signs of danger.

Both the behaviour-changing syringe and self-expiring packaging could have far-reaching impacts on global treatment, suggesting a world in which no one has to guess if their medicine is safe to use – but only if the big pharmaceutical companies are prepared to take the initiative and put these innovations into production.