Needlestick Injuries and Post Exposure Prophylaxis

Phyu Min Thet, Kaung Myat Aye, Nay Htet

In this article, we will be covering risk assessments, baseline testing, follow up and post exposure prophylaxis (if indicated) for blood-borne viruses Hepatitis B, Hepatitis C and HIV.

Firstly, it would be prudent to understand some important key definitions.

• Blood, CSF, pleural, peritoneal, pericardial and amniotic fluid are considered as high- risk body fluids.
• Urine, vomitus, faeces, sputum, gastric secretions and saliva are considered as low-risk body fluids. Usually, these are not considered as a risk unless they are visibly stained with blood.
• “Inoculation incident” is defined as an occurrence during which exposure to blood or bodily fluid occurs.

There are two types of inoculation incident/injuries: percutaneous and mucocutaneous.

Percutaneous exposure occurs when the skin is penetrated and broken by a sharp object. Risk of infection with Hepatitis B virus in unvaccinated individuals following a sharp or plash injury from a Hepatitis B positive source patient, is approximately 1 in 50, but it can be increased to 1 in 3 if the source patient is also HBe antigen positive (HPA,2008). In terms of risk of infection following a needle stick injury from a patient living with untreated hepatitis C is 1 in 30 (DoH 2008).

The average risk of HIV transmission after percutaneous exposure from a needle stick injury, from a person living with uncontrolled HIV in health care settings is approximately 1 in 300 (Department of Health 2008). Again, risk of HIV transmission after a bite, from a person living with uncontrolled HIV is negligible. But risk may be increased if saliva is visibly contaminated with blood, severe and/or deep tissue injuries and even more so if the donor has a high viral load (BASHH 2021).

Mucocutaneous exposure occurs when the mucous membranes of the mouth, nose, eyes or non-intact skin become contaminated with bodily fluid. It carries a lower risk of blood borne virus infection in approximately 1 in 1000 for HIV. Currently there is no evidence on the risk of transmission of Hepatitis B or Hepatitis C from mucocutaneous exposure (DH, 2008).

Management of inoculation incident

The most important thing will be to perform first aid. For skin exposure, it is important to wash with soap and water. Small wounds and punctures should be cleansed with antiseptics i.e alcohol based hand hygiene solution. Alcohol is virucidal to HIV, HBV and HCV. For mucosal exposures, the exposed mucous membranes should be flushed with copious amount of water. Eyes should be irrigated with saline or water.

Once this is completed, risk assessment should take place as soon as possible. Ideally, risk assessment should be carried out by a dedicated and competent person who works in clinical area and involved in the care of source patient. In UK, the recipient should contact occupational health. And for out of hours, the recipient should attend emergency department for bloods and assessment. And there should be reporting actions for all inoculation incidents and recorded on Datix recording system. Injuries from a source patient known to have a blood borne viruse must be reported to the Health and Safety Executive (HSE) under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulation (RIDDOR) by the Health and Safety Team after discussion with the Clinical/Department managers and these will also require a mini RCA (root cause analysis) investigation.

Nature of action taken and prophylaxis offered following an inoculation incident/ needle stick injuries will depend on a number of factors (type of injury, donor known to have HIV, HBV and HCV, depth of injury, visible blood on the device, ..etc). Post exposure prophylaxis can be given up to 72 hours after the exposure but the earlier it can be given , the better the outlook.

Protection against Hepatitis B

As stated above, the risk of infection with Hepatitis B virus in unvaccinated individuals following a sharp or plash injury from a Hepatitis B positive source patient, is approximately 1 in 50, but it can be increased to 1 in 3 if the source patient is also HBe antigen positive (HPA,2008). And the immediate action in post exposure period will depend on 2 factors –

1. Vaccination status of recipient/healthcare worker
2. Hepatitis B surface antigen status of the donor/ source patient

Below is the algorithm guiding Hepatitis B baseline testing and follow up

Fig.1. Flowchart illustrating hepatitis B baseline testing and follow up

Protection against HIV –

Risk of HIV transmission from a percutaneous exposure (‘sharp injury’) from an HIV-positive index case NOT on suppressive ART (anti-retroviral therapy) is estimated to be 0.3% (i.e 1 in 333). And risk of HIV acquisition from a mucocutaneous ‘splash injury’ is estimated to being around 0.1% (1 in 1000 exposures) if the HIV-positive index case is not on ART. Risk of HIV transmission through non-intact skin (e.g abrasions, cut, sores) is considered negligible.

Regrading biting and spitting, a systematic review was conducted to review the risk of HIV transmission through biting or spitting in 2018. And there were no reported cases of HIV transmission relating to spitting, supporting the conclusion that there is no risk of HIV transmission from spitting. Overall risk of acquiring HIV from a bite by an HIV positive person is negligible. But the risk is increased by the presence of blood in the saliva along with a high viral load of the perpetrator and the depth of the inflicted wounds.

Studies have shown that there may be a window of opportunity to prevent acquisition of HIV infection following exposure by inhibiting viral replication or preventing dissemination of infection i.e if ART is started as soon as possible. Once HIV crosses a mucosal barrier, it may take up to 48 hours before it begins to replicate and up to five days before HIV can be detected in blood. Initiation of ART has been shown to reduce dissemination and replication of virus in tissues when initiated early (<72 hours) after inoculation in a macaque animal model, though HIV infection is not universally prevented even if PEP is initiated within 4 hours.

When it comes to data supporting use of post exposure prophylaxis (PEP) to prevent HIV transmission, animal studies have shown that PEP is most effective when administered within 24 hours of exposure, with possible efficacy up to 72 hours post-exposure, and with a duration of 28 days. It is not feasible to perform human studies due to the ethics of withholding a potentially efficacious treatment.

In terms of occupational exposure to HIV, retrospective case-control study among health care workers occupationally exposed to HIV between 1983 and 1994 demonstrated that a 28-day course of Zidovudine was highly protective, resulting in an 80% reduction in HIV seroconversions compared to those who did not receive post exposure prophylaxis.

When to prescribe post-exposure prophylaxis (PEP) following occupational exposure

HIV positive index case

• PEP is recommended following a high-risk injury (sharps or mucosal splash) if the index case is known to be HIV positive and is not on ART for > 6 months with a suppressed viral load within the last 6 months (1C)
• PEP is generally not indicated following a sharps injury if the index case has been on ART for at least 6 months with an undetectable HIV viral load (at the time if last measurement and within the previous 6 months) and reported good However, due to lack of direct evidence, a case by case decision can be made depending on the nature of injury (2C)
• PEP is not recommended following a splash injury if the index case is known to have sustained undetectable viral load (1C)
• PEP is not recommended where there is no or negligible risk of HIV transmission e.g through intact skin that comes into contact with HIV infected blood or other bodily fluid (1C)

Index case of unknown HIV status

• PEP is not recommended following a sharps or mucosal splash injury if the index case is untested but from a low risk group (1C)
• PEP is generally not recommended following a sharp or mucosal splash injury if the index case is untested and from a high-risk group (i.e man who have sex with man and people who inject drugs), unless there were other factors that increased likelihood of transmission (e.g a deep injury or blood bolus injected or sharp injury from people who inject drug in the context of a local outbreak (1C)
• All efforts should be made to seek prompt voluntary HIV testing of the index case (1C)
• Index case HIV testing should not delay PEP initiation where indicated(GPP)
• If the index case is unable to give informed consent for HIV testing (e.g unconscious, altered mental status) then HIV testing can be performed if it is the best medical interest of the index case (GPP)

When deciding whether post exposure prophylaxis (PEP) is indicated where HIV status of the index case is unknown and not obtainable or pending HIV test result, the probability of the index case being HIV-positive must be estimated from

Risk of HIV transmission = risk that source is HIV positive with a detectable HIV viral load x risk per exposure *

*1/333 for needle stick injury; *1/1000 for splash injury

For example, a female of British origin has a prevalence of detectable HIV viraemia of 0.1 in 1000 or 1/10,000 , which when multiplied by the risk of transmission from a needle stick injury (1/333) give a transmission risk from the incident of: 1/10,000 x 1/333 = 0.0000003 or 1/3,333,333. So, in the above example of a needlestick from a British female of unknown HIV status, PEP would not be recommended as the risk is negligible.

Needlestick injuries in the community

• PEP is not recommended following a community needlestick exposure (2D)

PEP is not recommended following a community needlestick exposure as the risk is extremely low and usually not possible to determine :

1. whether the needle has been used and for what purpose
2. the HIV status of the index case and
3. the interval between the needle use and the exposure.

Human bites

• In general PEP is not recommended following a bite as, although the precise risk of transmission is unknown, it is likely to be negligible (2D)
• However, PEP could be considered for patients who fulfil ALL of the three following criteria –
  a. The biter’s saliva was visibility contaminated with blood;
  b. The biter is known or suspected to have a plasma HIV viral load>3.0 log copies/ml; andc. The bite has resulted in severe and/or deep tissue injuries

 

What to prescribe for post-exposure prophylaxis

First-lines

• We recommend the use of tenofovir disoproxil 245mg/emtricitabine 200 mg and raltegravir 1200 mg once daily as the regimen of choice for PEP (1B)
• If there is evidence that the index case has a current or past history of ART failure, expert advice should be sought as to whether the PEP regimen should be modified in relation to ART history and/or resistance testing (1D)
• For women who are pregnant, raltegravir 400 mg twice daily is preferred (with tenofovir disoproxil 245mg/emtricitabine 200mg). Where accessing raltegravir 400mg might cause delay we recommend using raltegravir 600 twice daily and switching at the earliest opportunity (1D)

Alternatives Recommended combination

• Tenofovir disoproxil 245mg/emtricitabine 200 mg one tablet once daily PLUS raltegravir 1200 mg once daily.

Other alternative combinations please see https://www.bashh.org/_userfiles/pages/ files /resources/pep2021_2023amendment.pdf

Side effects

• Where an individual reports significant current or previous intolerance to one or more PEP agents, an alternative agent(s) should be considered (2D)

Drug-drug interactions

• An accurate verified medication history should be obtained, including the use of over-the-counter medication, vitamins/minerals, herbal remedies and recreational drugs before PEP is prescribed to ensure no significant drug-drug interactions are present (1D)

Timing and duration of PEP –

• PEP should be initiated as soon as possible after exposure, preferably within 24 hours, but can be considered up to 72 hours (1D)
• We do not recommend initiating PEP beyond 72 hours after exposure (1D)
• The duration of PEP should be 28 days (1D)

• Individuals receiving PEP from an emergency or urgent care service should be seen as early as possible by their occupational health department.
• PEP should not be withheld until such expertise is available.
• For occupational exposures, the occupational health service has the responsibility for testing of the index case in conjunction with the attending practitioner and according to local policy which defines roles and responsibilities, advice to the PEP user during the course and the follow-up blood testing

Initiating PEP

• Routine blood test monitoring after initiation of integrase inhibitor-based PEP is not necessary unless clinically indicated or if baseline blood tests are abnormal (2C)
• Take a contraceptive history and perform pregnancy testing in all women of childbearing age considering PEP and offer emergency contraception where indicated (1D)
• Pregnancy and breastfeeding should not alter the decision to start PEP (2D)
• Women must be counselled that antiretroviral agents used for PEP are unlicensed in pregnancy and their risks/benefits must be carefully discussed (1D)
• An ultra-rapid course of Hepatitis B vaccination should be offered if clinically indicated in the absence of baseline immunity (1B)
• Use of starter packs can negatively impact the completion of PEP, therefore a full course of PEP should be provide at the fist attendance unless there are operational reasons why this is not possible (1C)

Baseline testing – baseline BBV testing of the index case

• Following occupational exposures informed consent for testing for blood borne viruses (fourth generation HIV test (HIV-1 Ag/Ab), hepatitis B surface antigen (HBsAg), Hepatitis C antibody (Hep C Ab) should be sought from the index case by another member of staff who is not the recipient of the occupational exposure (GPP)
• If the index case is a child then age appropriate HIV, HBV and HCV testing should be used -depending on age and developmental stage of child, consent from the parent or legal guardian of the child, and consent or assessment from the child. Discuss with a clinician with relevant expertise (e.g paediatric ID consultant, paediatric ID/microbiologist/virologist) if uncertain. (GPP)
• Where the index case is high risk of hepatitis C (eg. people who inject drug) then hepatitis C PCR or hepatitis C antigen can be done instead of Hepatitis C Ab. (GPP)
• Where it is not possible to seek consent from the index case (e.g patient comatose or lacks mental capacity then testing can be undertaken if it is in the best interests of the index case. (GPP)

Table 2 Follow-up testing

References

1. British HIV Association (BHIVA).PEP guidelines. Available at: https://bhiva.org/ clinical-guideline/pep-guidelines/
2. Ramsay, M. (ed.). (2021) Immunisation against infectious disease (Green Book). 2021 edn [PDF]. London: UK Health Security Agency. Available at: https:// assets. publishing.service.gov.uk/media/6196386dd3bf7f054f43e02d/Greenbook-cover Nov21.pdf
3. Bourry, O. et al. (2009) ‘Prevention of vaginal simian immunodeficiency virus transmission in macaques’, AIDS, 23(4), pp. 447–454. doi: 10.1097/QAD.0b013e 328321302d https://pubmed.ncbi.nlm.nih.gov/19240457/
4. Owusu, M.W., Wellington, E., Rice, B., Gill, O.N. and Ncube, F. (2014) Eye of the Needle: United Kingdom surveillance of significant occupational exposures to bloodborne viruses in healthcare workers [Online]. Available at: https://www. researchgate.net/publication/286876782_Eye_of_the_Needle_United_Kingdom_Surveillance_of_Significant_Occupational_Exposures_to_Bloodborne_Viruses_in_Healthcare_Workers

Author Information

Phyu Min Thet, Kaung Myat Aye, Nay Htet
Leeds Teaching Hospitals NHS Trust