Ultrasound probes are a potential source of HPV infection, posing a new challenge for infection prevention.
HPV – The facts
HPV is a serious sexually transmitted infection that can lead to cancer. As it becomes more prevalent, patients and clinical staff are increasingly at risk from HPV cross contamination infection.
HPV is one of the most commonly transmitted sexually transmitted infections, so common that most sexually active men and women will have an infection at some point.1,2
High-risk HPV can cause cancer
HPV is an infectious cause of cancer, associated with 5% of all cancers worldwide.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 The high risk strains HPV16 and HPV18 together cause 70% of all cervical cancers.2
In 2016, it was estimated that 2,659 women were diagnosed with cervical cancer in the UK and 979 died from the disease.5
In Ireland, these numbers were estimated to be 357 and 101 respectively.6
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.7 The HPV virus can survive and remain infectious on surfaces, including medical equipment, for days or weeks, when treated with common disinfectants.8 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.9-11
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. At that time, only trophon was shown to successfully kill HPV 16 and HPV 18.
1. Meyers J, Ryndock E, Conway MJ, Meyers C, Robison R. Susceptibility of high-risk human papillomavirus type 16 to clinical disinfectants. J Antimicrob Chemother. 2014;69(6):1546-50.
2. Ryndock E, Robison R, Meyers C. Susceptibility of HPV16 and 18 to high level disinfectants indicated for semi-critical ultrasound probes. J Med Virol. 2016;88(6):1076-80.
The 2015 study – only trophon kills high-risk HPV16/18
1. Public Health England. Genital warts and human papillomavirus (HPV): guidance, data and analysis. Website updated 7 October 2016. https://www.gov.uk/government/collections/genital-warts-and-human-papillomavirus-hpv-guidance-data-and-analysis . Accessed 21 June 2017.
2. Taylor S, Bunge E, Bakker M, Castellsagué X. The incidence, clearance and persistence of non-cervical human papillomavirus infections: a systematic review of the literature. BMC Infectious Diseases. 2016;16:293.
3. Parkin DM. The global health burden of infection-associated cancers in the year 2002. International journal of cancer. 2006;118(12):3030-44.
4. Walboomers JM, Jacobs MV, Manos MM, Bosch FX, Kummer JA, Shah KV, et al. Human papillomavirus is a necessary cause of invasive cervical cancer worldwide. J Pathol. 1999;189(1):12-9.
5. ICO Information Centre on HPV and Cancer. United Kingdom – Human Papillomavirus and Related Cancers, Fact Sheet 2016. Available from: http://www.hpvcentre.net/statistics/reports/GBR_FS.pdf.
6. ICO Information Centre on HPV and Cancer. Ireland – Human Papillomavirus and Related Cancers, Fact Sheet 2016. Available from: http://www.hpvcentre.net/statistics/reports/IRL_FS.pdf.
7. Meyers J, Ryndock E, Conway MJ, Meyers C, Robison R. Susceptibility of high-risk human papillomavirus type 16 to clinical disinfectants. J Antimicrob Chemother. 2014;69(6):1546-50.
8. Ryndock EJ, Meyers C. A risk for non-sexual transmission of human papillomavirus? Expert review of anti-infective therapy. 2014;12(10):1165-70.
9. Casalegno JS, Le Bail Carval K, Eibach D, Valdeyron ML, Lamblin G, Jacquemoud H, et al. High risk HPV contamination of endocavity vaginal ultrasound probes: an underestimated route of nosocomial infection? PloS one. 2012;7(10):e48137.
10. Ma ST, Yeung AC, Chan PK, Graham CA. Transvaginal ultrasound probe contamination by the human papillomavirus in the emergency department. Emergency medicine journal. 2013;30(6):472-5.
11. M’Zali F, Bounizra C, Leroy S, Mekki Y, Quentin-Noury C, Kann M. Persistence of Microbial Contamination on Transvaginal Ultrasound Probes despite Low-Level Disinfection Procedure. PloS one. 2014;9(4):e93368.
12. Ryndock E, Robison R, Meyers C. Susceptibility of HPV16 and 18 to high level disinfectants indicated for semi-critical ultrasound probes. J Med Virol. 2016;88(6):1076-80.