Health Matters with Dra. Denise: Needlestick Exposures

Recently, I was asked about the risks of used needles found in the community so thought I’d talk about this in today’s column. Whether you’ve come across used needles or not, they are present in Manitoba, and their occurrence has increased related to the increases in crystal meth and opioid injection drug use.

Generally used needles people come across in our community come from injection drug use outdoors, possibly related to unstable housing among those who use drugs.

While the perceived risk of finding a used needle is quite high, the actual health risk to the general public (including kids) of finding one is actually pretty low. The main theoretical risks from finding/getting poked by used needles are the blood-borne infections: hepatitis B, hepatitis C and HIV. There have certainly been increases in these infections in Manitoba related to shared injection drug use equipment. There are also increases seen in other illnesses, such as endocarditis directly related to injection drug use and non-sterile technique. But finding and getting poked by a used needle is not the same as injecting drugs yourself and sharing needles with other drug users. The risks are also very different from needlestick injuries a health care provider may experience at work. Community needle stick injuries are rare.

Hepatitis B

Hepatitis B is caused by infection with hepatitis B virus (HBV). HBV is the most stable of the blood-borne viruses and can be transmitted by a very tiny amount of blood. The risk of acquiring HBV from needle stick injury at work when the source is hepatitis B surface antigen (HBsAg)-positive ranges from 2% to 40%, depending on the source’s virus level in the blood. HBV can survive for up to one week under optimal conditions and has been detected in discarded needles. A case of HBV acquired from a discarded needle used by a known HBV carrier has been reported. While HBV vaccine is recommended for all children in Canada, most programs target children who are older than the usual age at which they sustain accidental needle stick injuries. Thus, the majority of injured children are likely to be susceptible to HBV infection. Management with anti-HBV immunoglobulin and HBV vaccine is effective if provided promptly.

Hepatitis C

Hepatitis C is caused by infection with the hepatitis C virus (HCV). The risk of acquiring HCV from a needle stick injury at work when the source was infected varies from 3% to 10%. HCV is thought to be a fragile virus which would be unlikely to survive in the environment. There has been a case report of HCV acquisition after an injury from a discarded needle.

Unfortunately, there is no effective treatment to prevent acquisition once poked. It is important to determine whether a potential exposure results in HCV transmission because 50 to 60% of infected children will have persistent, asymptomatic infection which requires follow-up by a specialist. Chronic hepatitis will eventually develop in some of these cases, and antiviral treatment may be required.

Human Immunodeficiency Virus (HIV)

The risk of acquisition of HIV from a hollow-bore needle with blood from a known HIV-positive source is between 0.2% and 0.5%, based on studies of occupational needle stick injuries. The risk is increased with a larger amount of blood introduced and higher concentration of virus in that blood. The size of the needle, the depth of penetration and whether blood was injected are also important considerations. In most reported instances involving transmission of HIV, the needle stick injury occurred within seconds or minutes after the needle was withdrawn from the source patient.

In contrast to the situation with health care worker needlestick injuries, the source of blood in discarded needles is usually unknown, injury does not occur immediately after needle use, the needle rarely contains fresh blood, any virus present has been exposed to drying and environmental temperatures, and injuries are usually superficial. HIV is a relatively fragile virus and is susceptible to drying. However, survival of HIV for up to 42 days in syringes inoculated with the virus has been shown, with duration of survival dependent on ambient temperature.

It is extremely unlikely that HIV infection would occur following an injury from a needle discarded in a public place. There have been no reported cases of HIV transmission from needle injuries in the community.

However, if the incident involved a needle and syringe with fresh blood, and if some of the blood was injected, infection is theoretically possible, and treatment is indicated.

Safe disposal saves you, and others, from injury.

If you find a discarded needle in a public place, you can follow these steps to safely dispose of the needle:
1) Find a rigid plastic container with a secure lid (i.e. laundry detergent or bleach bottle). Thinner plastic containers like pop bottles are less puncture-resistant so should only be used if there is no alternative. A container that stands on its own with a sufficiently wide mouth is ideal.
Remove the lid and place the container on the ground beside the needle.
2) Use rubber gloves, or tongs to pick up the needle by the centre of the barrel.
Always point the sharp end down and away from you. Don’t hold the container while you are dropping in the needle.
3) Do not break or recap the needle.
4) With the plastic container still on the ground, put the needle in the container sharp-end first, and secure the lid.
5) Wash your hands thoroughly with soap and water.
6) Safely dispose of the sealed container—not in recycling! Disposal locations vary across the province; in some jurisdictions it is common practice to throw these containers in the trash. You can check which has an interactive map of harm reduction supply distribution and needle drop-off locations in Manitoba.

If you are poked by a needle:
Don’t panic.
The risk of infection is low.
Wash the affected area with soap and water.
Seek medical attention immediately.
If you are not comfortable with picking a discarded needle up, call 311, or your municipal waste and water department, for collection options.
Kung may tinanim, may aanihin; health starts at home. Alagaan ninyo ang katawan at kalusugan ninyo! Take care, and mind your health!

About Dr. Denise Koh

Dr. Denise Koh is Manitoba’s Chief Occupational Medical Officer and a Medical Officer of Health in Environmental Health and Emergency Preparedness. She is a Public Health specialist with additional training and experience in Family Medicine and Occupational Medicine. Follow her writing at: