Yet another regional news report, this time from Australia’s Sunshine Coast, of a sharps injury from a needle discarded into undergrowth garden borders of a holiday complex and lost in a layer of mulch until disturbed by an unfortunate gardener.

As always, he now faces an anxious wait to see if he has contracted HIV, Hepatitis B or Hepatitis C. The first test results, which showed no sign of infection, give some hope that all will be OK but the wait is a long one and the next results are due August 25, with the final test in December.

An interesting comentary added to the news report cuases concern:

Sadly, that is not the case though it is a widely held and potentially dangerous belief. There is good evidence to suggest that a deep injury from a large hollow needle is a far greater risk than is a superficial wound from a solid needle or blade. Who wants to take the chance?

HIV, HBV and HCV decline rapidly outside the body though at 4C survival can be measured in weeks rather than days. Dismissed as the conditions of the laboratry refigerator, is this true also of refrigerated wastes, or wastes at low temperature during the winter months.

Survival depends on the virus titre (concentration), the volume of blood, temperature and humidity, and exposure to direct sunlight. Dessicaton is important and studies with Hepatitis C show rapid loss of infectivity, with 4 days not 45 minutes, on drying. Other detailed studies left Hep C virus at room temperature for 16 h, 4 days and 7 days and noted iInfective virus only at 16 hours with no surviving virus at 4 days and 7 days.

HIV survives somewhat longer. Studies show that at 20 – 30ºC, survival reduced to ~8% positivity within 21 days but at 4ºC, increases to 50% positivity at 42 days. This is confirmed by complimentary studies that define the limit of survival at optimum conditions exceeding 6 weeks.

The problem is, when an unexpected sharps injury or other exposure happens, from discarded drug paraphernalia or from clinical and related wastes, the “age” and storage conditions of that item are unknown. The item causing injury may also be unknown if it remains lost within waste and the question of hollow needles or solid becomes something of a guessing game.

The source patient will be unknown precluding any possibility of testing of that source patient though tests can be run on the contents of a discarded needle if it is retained for examination.

Interestingly, almost every clinical protocol rates sharps injury from an unknown source as high risk warranting immediate specialist care, appropriate prophylactic drug therapies and long follow-up. This is supported by evidence from the UN World Drug Report that records a high prevelence of HIV, Hep B or Hep C in IV drug users. About half the world’s injecting drug users, about eight million people, are infected with Hepatitis C, and that basis the chance of the user of a discarded needle being Hep B positive is around 22% and for Hep C about 50%.

Dismissing the risks associated with sharps injury or other exposure to discarded drug litter or other clinical wastes is a dangerous game. Though we must hope that the gardener is OK, the risks cannot be ignored and every sharps injury requires careful clinical assessment and follow-up. That should necessitate a standard of priority care mandated for healthcare professionals under European Union Council Directive 2010/32/EU that is presently restricted only to those healthcare professionals, others seem to take pot luck.

Lastly, the naysayers are claiming that the introduction of engineered sharps safety devices will lessen still futher the risks of infection from sharps injury. Safety needles are not presently issued to IV drug users – that is probably a long way off, and may not work as expected since manual activation of those syringes/needles would prevent needle sharing at street level. It requires also an expectation of some responsible action on the part of users who presently show callous disredgard for the safety of others. Thatr is not likely to change.