Ultrasound probes are a potential source of Human Papillomavirus (HPV) infection, posing a new challenge for infection prevention.
HPV – The facts
HPV is a serious sexually transmitted infection that can lead to cancer. It is associated with 5% of all cancers worldwide.1
As it becomes more prevalent, patients and clinical staff are increasingly at risk from HPV cross contamination infection.
HPV is extremely common. It is estimated that more than 70 per cent of sexually active Canadian men and women will have a sexually transmitted HPV infection at some point in their lives.2
High-risk HPV can cause cancer
High risk types of HPV (16 and 18) cause approximately 70% of anal and genital cancers.3
High-risk HPV can cause cervical cancer as well as cancer of the vulva, vagina, rectum and the penis. Intracavity ultrasound is commonly performed in these body sites and HPV can be spread by cross contamination.
Research shows that virtually all cervical cancers (more than 99%) are caused by high-risk HPV.4
An estimated 1,550 Canadian women were diagnosed with cervical cancer in 2017 with 400 deaths from it.5
The risk of HPV transmission from ultrasound probes
As well as being transmitted sexually, HPV can be passed from one person to another via intracavity or surface ultrasound probes, if probes are not adequately disinfected before use. This alarming reality is backed up by clinical evidence.
Studies show that common disinfection methods, even high level disinfection (HLD) methods, don’t kill the cancer-causing HPV on ultrasound probes.6 The HPV virus can survive and remain infectious on surfaces, including medical equipment, for days or weeks, when treated with common disinfectants.7 Research shows that up to 7% of intracavity probes used in ultrasound examinations remain contaminated with high-risk HPV DNA even after low or intermediate level disinfection.8,9,10
Learn more about HPV disinfection
Studies showing susceptibility of HPV to disinfectants1,2.
In 2014 a study was conducted in testing typical hospital disinfectants against real native HPV2.The testing concluded that the following disinfectants did not kill HPV16: Ethanol; Isopropanol, GTA, OPA; Phenol; 0.25% PAA-silver. Note: whilst 1.2% PAA-silver and 0.525% Hypochlorite were shown to produce a reduction in infectivity, they are not appropriate to use as chemical disinfectants for ultrasound probes.
In a further clinical study in 2015 surface carrier tests against HPV16 and HPV18 were carried out using trophon. The testing was conducted according to manufacturers’ instructions to simulate normal clinical use conditions (concentration, time, temperature)1. trophon was shown to successfully kill HPV 16 and HPV 18.
1. Ryndock E, Robison R, Meyers C. 2015. Susceptibility of HPV16 and 18 to high level disinfectants indicated for semi-critical ultrasound probes. J Med Virol. Published online 13 Nov 2015. DOI 10.1002/jmv.24421.
2. Meyers, J., et al., Susceptibility of high-risk human papillomavirus type 16 to clinical disinfectants. J Antimicrob Chemother, 2014.
The 2015 study – only trophon kills high-risk HPV16/18
- Parkin OM (2006). “The global health burden of infection-associated cancers in the year 2002”. Int. J. Cancer 118 (12): 3030-44.
- Watson M, Saraiya M, Ahmed F, et al. Using population-based cancer registry data to assess the burden of human papillomavirus-associated cancers in the United States: overview of methods. Cancer 2008; 113(10 Suppl):2841- 2854.
- Meyers, J., et al., Susceptibility of high-risk human papillomavirus type 16 to clinical disinfectants. J Antimicrob Chemother, 2014.
- Ryndock EJ, Meyers C., A risk for non-sexual transmission of human papilloma virus? Expert Rev. Anti Infect. Ther. 12(10), 1165-1170 (2014).
- Casalegno et. Al.: High Risk HPV Contamination of Endocavity Vaginal Ultrasound Probes: An Underestimated Route of Nosocomial Infection?, PLOS ONE, Oct 2012, Volume 7, Issue 10
- Ma et al.: Transvaginal ultrasound probe contamination by the human papillomavirus in the emergency department, Emerg Med J, 2012
- M’Zali et al. Persistence of microbial contamination on transvaginal ultrasound probes despite low-level disinfection procedure. PLoS One 2014;9:e93368.
- Ryndock E, Robison R, Meyers C. 2015. Susceptibility of HPV16 and 18 to high level disinfectants indicated for semi-critical ultrasound probes. J Med Virol. Published online 13 Nov 2015. DOI 10.1002/jmv.24421.