Needle stick injuries are common and can transmit many blood-borne pathogens

Reviewed by Kate Anderton, B.Sc. (Editor)Aug 25 2019

Needle stick injuries (NSIs) can transmit more than 20 blood-borne pathogens, including HIV, hepatitis B virus (HBV), hepatitis C virus (HCV) and, more rarely, malaria, human T cell leukemia virus and Ebola. Indeed, a milliliter of blood can contain between 10⁵ to, rarely, 10¹⁴ HIV particles, a viral load that may exceed the number of trees on earth (3 trillion). Worldwide, occupational sharps exposure seems to be responsible for about 40% of HBV and HCV infections and 2.5% of HIV infections among healthcare professionals (HCPs).

To address the risk of NSIs, the European Union (EU) and the US Occupational Safety and Health Administration (OSHA) have issued guidance to help protect HCPs from bloodborne pathogens.

The OSHA Bloodborne Pathogens standard states that safety "engineering and work practice controls shall be used to eliminate or minimize employee exposure", such as the use of sharps with a safety engineered injury protection mechanism.

In Europe, the EU Directive 2010/32 implemented a framework agreement on prevention from sharp injuries in the hospital and healthcare sector. This includes an assessment to eliminate the risk of NSIs. The risk management measures include providing safety-engineered medical devices, safe disposal and adequate training.

The EU-OSHA highlights a study carried out at the University Hospital of Heidelberg in Germany on behalf of the State Health Office Baden-Wurttemberg. This controlled study showed a significant statistical reduction in NSIs in a group using safety devices over a 12-month period.

Passive safety pen needles are the first type of safety-engineered devices designed to prevent NSIs when HCPs are using injection pens to administer medication to their patients. The use of these passive safety pen needles is explored in an international survey, carried out by an independent research company, which will be published in a white paper in September.

The survey, carried out with more than 200 HCPs who use passive safety pen needles, confirmed that there is concern about NSIs and that HCPs prefer to use these safety devices.Four in five agreed that using a safety pen needle increases protection against NSIs compared with the conventional pen needle. However, the majority of respondents also said that there were practical challenges in using passive safety needles which are highlighted later in this paper.

A common problem

Sharps injuries are common among HCPs. In England, for example, the number of exposures to bloodborne viruses increased by 33% from 373 in 2004 to 496 in 2013 despite safety regulations and the availability of passive safety devices. The number of reported percutaneous injuries increased by 22% during the same time from 283 to 344. A systematic literature review reported that - depending on the country, setting and methodology - up to 69% of HCPs experienced a NSI. However, a third of European nurses, 38% of trainee doctors and 52% of surgeons did not report their NSI. So, the number of NSIs is probably higher than official estimates suggest.

NSIs can occur at several stages during the injection process: 14% of NSIs among trainee doctors and 30% among nurses treating diabetes occurred when recapping a needle.^{11, 12}A French study found that injection pens accounted for 39% of NSIs associated with subcutaneous injection, a rate six times higher than with disposable syringes. About 60% of NSIs occurred during disassembly of the pen, a rate about six times higher than during recapping of a disposable syringe.

The physical and psychological burden

A sharps injury can be traumatic, physicallyand psychologically. The risks of contracting HBV following a sharps injury is about 1 in 3. The risk of HCV and HIV (1:30 and 1:300, respectively) transmission is lower than that for HBV. Nevertheless, the risk after a NSI is much higher than following mucosal exposure to infected body fluid, which is less than 1 in 1000 for HIV. Numerous factors influence the risk including the type of sharps injury, the patients' viral load, the HCP's immune status and local healthcare strategies, such as promptly using post-exposure prophylaxis.

The effects of a NSI are more than physical. A study from the UK found that 12% of trainee doctors who experienced a NSI showed evidence of post-traumatic stress disorder (PTSD), a rate about four times higher than in the general population. Another study enrolled 13 people with adjustment disorder and four with PTSD referred to a psychiatric trauma clinic after a NSI. Each month that the person waited for an all-clear result, increased the duration of the psychiatric disease by 1.8 months. Although none of the HCPs contracted an infection, the psychological illness associated with the NSI undermined occupational, familial and sexual functioning.

Survey reveals unmet need

As referenced earlier, the international survey found that 81% of 204 HCPs agreed that using a safety pen needle increases protection against NSIs compared with a conventional pen needle. Moreover, 83% would prefer to use safety pen needles than conventional pen needles.

However, as discussed in another blog in this series, there are some practical challenges in using passive safety needles. Of the HCPs questioned, 71% agreed that safety pen needles activate before they finished administering the injection. Of these, 69% agreed that premature activation of the safety mechanisms makes them unsure that the full dose of medication is delivered to their patient.

The findings of the survey suggest that there is a requirement for a balance between safety and control: 86% of the survey respondents agreed that it is equally important for a pen needle to provide both safety and control during the injection process.

This balance is being addressed. Owen Mumford, a company that has been at the forefront of medical device innovation for over 60 years, is bringing together world-class research, design expertise and engineering excellence to develop innovative methods to further reduce the risk of NSIs, while giving HCPs confidence regarding control of medication dose delivery.