20th February 2024

Blood-borne viruses (BBV)

Initial management 

This topic will not cover the clinical presentation, investigation or management of hepatitis B, C or HIV. This section aims to ensure candidates know the steps and advice that should be provided when a patient has been accidentally exposed to the body fluids of a suspected carrier of BBVs.  

It is crucial to determine the type of exposure ( Skin vs. mucous membrane vs. percutaneous) along with the type of body fluid the recipient was exposed to. The nature of exposure ( type of needle, the purpose of the needle, how soon the event occurred after contamination of the needle, whether the blood was fresh or dried) should be clarified. 

Following exposure, basic wound care should be undertaken with irrigation of skin, mucous membranes and wounds with soap and water. Antiseptic may be used to clean the wounds, which should be allowed to bleed freely. It is not encouraged to express blood or to suck blood from the wound. Eyes should be irrigated with water. 

It is essential to be aware of the risk of transmission. The risks are reduced for skin and mucous membrane exposure.

Table 1: Risk of infection transmission following a needlestick injury. Information extracted from Health and Safety Executive UK (Health and Safety Executive. (No date). Management of an exposure incident. Accessed on 2022 Mar 26. Available from: https://www.hse.gov.uk/biosafety/blood-borne-viruses/management-exposure-incident.htm. )

A baseline serology sample should be taken from the recipient for all individuals. If the source is not known to have any BBVs, they should be consented to a BBV screen and a serology sample. If the source is positive for any BBV, the stored baseline sample from the recipient will be tested. 

Hepatitis B 

Recipients exposed towards hepatitis B should be assessed for their vaccination status and previous hepatitis B status. It is also essential to know if the recipient is known to have responded to their hepatitis B vaccine if this had been taken. 

The timings and exact blood tests needed may vary between health boards, but NICE recommends blood to be taken at four intervals: baseline, 4-6 weeks, three months and six months post-exposure. HBsAg, anti-HBs and anti-HBc have been used to monitor the development of hepatitis B in this group.

Treatment can be provided using passive immunisation. Recipients known to have developed immunity towards hepatitis B via previous infection or successful vaccination do not require immunoglobulin treatment. NICE recommends administering a booster dose following significant exposure unless the patient has received a booster dose within four weeks of exposure. 

In recipients without proven hepatitis B immunity, post-exposure prophylaxis is indicated, provided with the hepatitis B vaccination and immunoglobulin. For most cases, the accelerated hepatitis B schedule is given with vaccines given at 0,1- and two months post-exposure. Their antibody titres should be checked within 1-4 months following completion of their vaccine course. NICE recommends the administration of immunoglobulin in this group of patients, but this should be discussed with the microbiologist before administration. 

Hepatitis C 

Recipients should be asked about any previous exposure towards hepatitis C. Blood tests should be taken from the recipient at baseline. If the source is positive for hepatitis C, further blood tests are required at weeks 6,12 and 24. Hepatitis C RNA levels are checked at weeks 6,12, and 14, while hepatitis C antibody tests are performed at weeks 12 and 24. 

No effective medications can be used as post-exposure prophylaxis against hepatitis C. If the recipient is found to have an active hepatitis C infection, a referral to a hepatologist should be made.  

HIV  

It is crucial to be sure of the source’s HIV status prior to commencing treatment. Post-exposure prophylaxis (PEP) and blood test monitoring are considered post-exposure. The combined HIV Ag/Ab test is used to monitor the development of HIV, and this is performed at baseline and three months post-exposure. The source’s serology should also be obtained to confirm/exclude the presence of HIV or other BBVs. PEP is often commenced prior to the results of the source’s HIV status if it is unknown. 

The British HIV Association (BHIVA) recommends against the use of post-exposure prophylaxis in cases where the needlestick injury has occurred from a discarded needle in the community. This is due to the difficulty in determining the index cases’ HIV status and the needle use, making the risk of acquiring HIV through this scenario negligible. 

If the index case’s HIV status is unknown or unobtainable, the likelihood of the index case being positive should be estimated based on the patient’s demographics and location. In cases where the probability of HIV transmission is felt to be low, PEP is not indicated. If the source is from a high-prevalence country or a high-risk population, this usually requires a discussion between the clinician and patient about the risks and benefits of PEP. This is because even in this population, the risk of transmission remains low. 

If the index case is positive, it is essential to know if the patient’s viral load is known. Index cases established on antiretroviral therapy with an undetectable viral load within the last six months are felt to be of low risk of transmission. PEP is not recommended in this case. 

If the viral load is elevated or unknown, PEP is recommended in most cases of occupational exposure. However, if the exposure has occurred on intact skin, PEP is not recommended. HIV transmission via human bites is variable, and PEP is usually not recommended in this case unless the following are fulfilled:

• Biter’s saliva was visibly contaminated with blood
• Biter is known or suspected to have an HIV viral load >3.0 log copies/ml
• Bite has resulted in severe/deep structure injuries. 

PEP is usually commenced within the first 72 hours but should be commenced as soon as possible following the exposure. PEP is not recommended beyond 72 hours post-exposure and should be taken for 28 days. A standard PEP regime includes two nucleoside reverse transcriptase inhibitors and an integrase inhibitor. Protease inhibitors may also be used as an alternative. Examples include tenofovir disoproxil/emtricitabine with raltegravir. Patients should be warned of potential side effects and drug interactions while on PEP. 

References

• Health and Safety Executive. (No date). Management of an exposure incident. Accessed on 2022 Mar 26. Available from: https://www.hse.gov.uk/biosafety/blood-borne-viruses/management-exposure-incident.htm. 
• National Institute for Health and Care Excellence clinical Knowledge Summary. (2022). Scenario: Prevention of infection with Hepatitis B. Accessed on 2022 Mar 26. Available from: https://cks.nice.org.uk/topics/hepatitis-b/management/prevention-of-infection-with-hepatitis-b/. 
• Public Health England. (2019). Guidance on management of potential exposure to blood-borne viruses in emergency workers. Accessed on 2022 Mar 27. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/835888/Guidance_on_management_of_potential_exposure_to_blood__2_.pdf. 
• Siedner, M. J., Tumarkin, E., & Bogoch, I. I. (2018). HIV post-exposure prophylaxis (PEP). BMJ, 363, k4928. doi:10.1136/bmj.k4928
• National Institute for Health and Care Excellence Clinical Knowledge Summary. (2020). How should I test for hepatitis C?. Accessed on 2022 Mar 26. Available from: https://cks.nice.org.uk/topics/hepatitis-c/diagnosis/how-to-test/ 
• Weber, D. (2020). Prevention of hepatitis B virus and hepatitis C virus infection among health care providers. Accessed on 2022 Mar 26. Available from: https://www.uptodate.com/contents/prevention-of-hepatitis-b-virus-and-hepatitis-c-virus-infection-among-health-care-providers?search=hepatitis%20b%20exposure&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H2957890262. 
• Cresswell, F., Asanati, K., Bhagani, S., Boffito, M., Delpech, V., Ellis, J., . . . Gupta, N. (2022). UK guideline for the use of HIV post-exposure prophylaxis 2021. HIV Med. doi:10.1111/hiv.13208