As the archive files of the Clinical Waste Discussion Forum will attest, several years before the start of the move toward introduction of engineered safety sharps I took a sceptical view of the protection that they might afford. Not for sharps users, the clinicians, nurses and scientists who might wield a syringe and needle to draw blood or administer an injection, but for those working as ancillary and support staff, and waste handlers, who might be exposed to used sharps as they pass along the disposal chain.

So sure was I that the potential reduction in injury would be manifest in fewer sharps injury events in ancillary and waste handlers that I placed a small wager with a colleague. It was will deep regret that I have been able to collect on that wager – a modest lunch – having seen the evidence of sustained carelessness in sharps disposal.

Has that claim really come true?

Sharps incidents and sharps injuries to waste handlers have reduced only where mechanisation and bulk handling of carts, as opposed to manual handling of individual clinical waste bags and sharps bins, reduces opportunity for direct contact. Even where this has been possible, waste containers are still managed by hand as they are removed from wards and clinics, generally by cleaners and other ancillary workers who might have access to latex gloves or a pair of Marigolds but who will never have the benefit of sharps-safe gloves.

Safety engineered sharps come in tow distinct types, passive devices that activate automatically, usually via a spring-loaded retraction mechanism, and active devices that need some positive action by the user to flip a shield over the exposed needle.

My hypothesis was that a) since the passive devices are more complex they will be more expensive, b) financial constraints will see many Trusts choose the cheaper active devices, and that c) careless failures to engage the safety features of those active safety sharps who result in many of these devices discarded without activation. This would result in no protection for those encountering the needle during its journey through the disposal chain. To make matters worse, would those who can’t manage activation of the sharps safety feature be so concerned to dispose of the used sharps with the required care, or would these unprotected sharps be found in an overfilled sharps bin, in a waste sack or in the soiled lined on its way to the hospital laundry?

A new research paper from France (Needlestick injury rates according to different types of safety-engineered devices: results of a French multicenter study. Infection Control and Hospital Epidemiology 2010; 31(4):402-7 DOI: 10.1086/651301 makes depressing reading. The authors objective was to evaluate the incidence of needlestick injuries (NSIs) among different models of safety-engineered devices (SEDs) automatic, semiautomatic, and manually activated safety) in healthcare settings. This was done by a multicenter survey involving no less that sixty-one hospitals in France, conducted from January 2005 to December 2006, examining all prospectively documented SED-related NSIs reported by healthcare workers to their occupational medicine departments. Participating hospitals were asked retrospectively to report the types, brands, and number of SEDs purchased, in order to estimate SED-specific rates of NSI.

More than 22 million SEDs were purchased during the study period, and a total of 453 SED-related NSIs were documented. The mean overall frequency of NSIs was 2.05 injuries per 100,000 SEDs purchased. Device-specific NSI rates were compared using Poisson approximation. The 95% confidence interval was used to define statistical significance. Passive (fully automatic) devices were associated with the lowest NSI incidence rate.

Among active devices, those with a semiautomatic safety feature were significantly more effective than those with a manually activated toppling shield, which in turn were significantly more effective than those with a manually activated sliding shield (p<0.001, Chi² test). The same gradient of SED efficacy was observed when the type of healthcare procedure was taken into account.

The authors conclude that passive SEDs, devices that do not require any action on the part of the user, are most effective for NSI prevention.

So perhaps we should expect that passive devices should be the gold standard safety-engineered device, for the protection of sharps users and inevitably therefore for the protection of ancillary and waste handlers.

And who else should we consider? Insulin-dependent diabetics not using insulin pens and IV drug users are particular problems since neither group is being offered safety-engineered sharps of any kind.

The devices look and feel differently and it takes some instruction and practice to use them effectively. For diabetics, that will involve a hugely complex and costly program of instruction – even if it takes just 2 minutes per patient that necessitates a hospital visit or GP appointment.

And for IV drug users, the probability for manual activation of a safety device after shooting up are probably small and possibly so small as to be negligible. For those clearing discarded sharps, the huge risk of injury and infection thus remains unchanged. There would (could?) be further advantages, since fully automatic and tamper-proof passive safety sharps are effectively single use only. This would eliminate needle sharing with a major impact on disease transmission rates among this vulnerable group.

Politics and public opinion will get in the way. Will it be accepted that IV drug users should be provided with expensive safety sharps? Would it be acceptable that they are trained in shooting-up? Should public money be spent in support of this group, even if there might be additional gains to society for reduced disease transmission rates though less needle sharing, and protection for those in the public sector who are tasked to clear discarded drug litter? The vociferous moral majority may well say no; there is considerable evidence for this with similar proposed public health interventions, for the creating of safe and accessible injection rooms that are provided in some other countries, or even the placement of secure sharps bins in high risk hot spots.

None of this bodes well for the safety of ancillary and waste handlers.