Needlestick injuries and post-exposure prophylaxis

Assess Exposure Risk

Many factors contribute to the risk of transmission of a blood borne pathogen, including the type of body fluid involved, the type of injury that occurred, the size of the inoculum, and the attributes of the source and exposed patient. All of the following information should be obtained and recorded.

Body fluid

• body fluids considered potentially infectious for hepatitis B, hepatitis C and HIV include blood, serum, plasma, visibly bloody fluids, semen, vaginal secretions, rectal secretions, cerebrospinal, synovial, pleural, peritoneal, pericardial and amniotic fluid
• body fluids NOT considered potentially infectious for a blood borne pathogen include feces, nasal secretions, saliva, sputum, sweat, tears, urine and vomitus, unless they are visibly bloody

Type of Injury/Exposure

• Occupational exposure:
  • percutaneous - skin puncture or laceration by needle or sharp object
  • mucosal - splash to mucous membranes (e.g. eyes, nose, mouth)
  • cutaneous - contact through nonintact skin (e.g. cuts, dermatitis)
• Non-occupational exposure:
  • sexual activity (eg. insertive or receptive, anal or vaginal intercourse)
  • needle sharing

Inoculum size

• volume of infectious fluid involved (e.g. hollow bore vs. solid needle; large volume vs. small volume splash)
• viral titre in the infectious fluid if known (e.g. well controlled disease vs. poorly controlled)

Source patient

• unknown for hepatitis B, hepatitis C, or HIV
• positive for hepatitis B, hepatitis C, or HIV
• stage of disease – risk of HIV transmission is 8-12X higher during the acute stage of HIV (first 6 months)
  • most recent viral load
  • current and past antiretroviral/antiviral use
  • known or suspected drug resistance
  • negative with no risk factors
  • negative with risk factors (e.g. men who have sex with men, multiple sexual partners, people who inject drugs)

Presence of sexually transmitted infections (in cases of sexual exposures)

• in both the source and exposed patient

Estimated risk of transmission

Following percutaneous exposure to blood or potentially infectious fluid:

• Hepatitis B: 6-30%
• Hepatitis C: 3-10%
• HIV: 0.23% (0.1% for mucous membrane exposure)

Exposure	Prob. per act (95% CI)
Parenteral
Blood transfusion	92.5% (89-96%)
Needle-sharing IDU	0.63% (0.41-0.92%)
Percutaneous needle stick	0.23% (0-0.46%)
Sexual Exposure
Receptive anal intercourse	1.38% (1.02-1.86%)
Insertive anal intercourse	0.11% (0.04-0.28%)
Receptive vaginal intercourse	0.08% (0.06-0.11%)
Insertive vaginal intercourse	0.04% (0.01-0.14%)
Receptive oral intercourse	very low (<0.05%)
insertive oral intercourse	very low (<0.05%)

The risk of transmission to receptive partner increases with ejaculation, presence of ulcers and sexually transmitted infections in the mucous membrane (oral, genital, rectal), and high viral load in the source (e.g. acute or late-stage disease).

Perform Baseline Testing

Since serologic testing of the source patient is the most reliable method to assess the risk of exposure, this is strongly recommended. Ascertain if the exposed individual is willing to be tested for antibody to hepatitis B, hepatitis C, and HIV. If the exposed individual is not willing to be tested, do not test the source patient unless they have a separate indication for testing.

Source patient, if available

• The source patient should be informed of the incident, and asked to undergo testing. Informed consent must be obtained (and for source patients admitted within the hospital, this must be documented in the chart by the attending medical staff or alternate medical delegate). If the source patient is a neonate, testing should be done on the mother.
• If the source patient does not consent to testing, an application can be made to the medical officer of health requiring mandatory blood testing to protect victims of crime, emergency service workers, and other persons. The application process can be found at: http://www.health.gov.on.ca/en/common/legislation/bill105/
• Tests:
  • HIV antibody using a fourth-generation combination p24-antigen-HIV antibody assay or rapid HIV test; if suspecting acute HIV, consider HIV RNA
  • Hepatitis B surgace antigen (HBsAg)
  • Hepatitis C antibody (HCV Ab); if positive, test hepatitis C RNA

Source patient, if not available

If the source patient is unknown or cannot be tested, consider their likelihood of having a blood-borne pathogen based on local epidemiology. e.g. what is the prevalence of infection in this population? Does the source have risk factors for infection?

Exposed individual

• If the exposed individual is not willing to be tested for HIV, HIV PEP should not be initiated
• Tests
  • HIV antibody using a fourth-generation combination p24-antigen-HIV antibody test or rapid HIV test; if suspecting acute HIV, consider HIV RNA
  • Hepatitis B serologies: HBsAg, antiHBsAb, anti-HBcAb
  • Hepatitis C antibody; if positive, test HCV RNA
  • If starting HIV PEP, add CBC, creatinine, and ALT
  • Pregnancy test, if appropriate
  • STI testing if sexual exposure
    • Syphilis serology
    • Gonorrhea and chlamydia cultures/NAAT from throat, vagina, rectum, and urine, as indicated

Hepatitis B Exposure

• Depends on the vaccination and antibody status of the exposed individual as well as the serologic status of the source
• If the exposed individual is immune (i.e. has HBsAb >10 after vaccination or natural immunity), then no further action is required
• If the exposed individual is not immune (i.e. never vaccinated, HBsAb <10, or has not completed vaccination series), then hepatitis B prophylaxis and vaccination may be required
• If the exposed individual's status is unknown, then immediately draw blood for HBsAb prior to giving hepatitis B immune globulin (HBIg) or vaccine, and proceeding as non-immune without waiting for status

Management

• May include HBIG and vaccination for those who are not immune or are of unknown status

Status (exposed)	HBsAb (exposed)	HBsAg (source)	Action
Unvaccinated	≥10	any	no further action
Unvaccinated	<10	negative	vaccinate
Unvaccinated	<10	positive or unknown	HBIG x1 and vaccinate
Vaccinated	≥10	any	no further action
Vaccinated x1	<10	negative	vaccinate
Vaccinated x2+	<10	negative	no further action
Vaccinated x1	<10	positive or unknown	HBIG x1, vaccinate
Vaccinated x2+	<10	positive or unknown	HBIG x2 q1mo
Vaccinated	unknown	any	measure levels, treat before results
Undervaccinated	any	negative	vaccinate
Undervaccinated	any	positive or unknown	HBIG x1, vaccinate

Hepatitis B immune globulin (HBIG)

• When indicated, it should be given as soon as possible, ideally within 24 hours but up to 7 days (with decreasing efficacy)
• Dose is 0.06 mL/kg body weight IM, divided into two separate doses
  • Dose should be repeated in 1 months if they are a known non-responder with HBsAb <10 after completing a vaccination series

Hepatitis B vaccine series

• 3 dose series in all patients that have not been immunized
• Given at a site separate from the HBIg
• Can give a second 3-dose series if they are a non-responder after the first course

Counselling and follow-up

• Counselled on signs and symptoms of hepatitis within the next 6 weeks to 6 months
• Follow-up testing including
  • HBsAg at 6 months, for seroconversion in unimmunized patients
  • HBsAb 1-2 months after completing the vaccine series (or 6 months after, if they received HBIg)

Hepatitis C Exposure

• No prophylaxis
• Counsel on signs and symptoms of hepatitis
• Follow HCV antibody at 3 and 6 months if source is HCV positive or unknown

HIV exposure

Indications for PEP

Occupational exposures

• Percutaneous or mucous membrane exposure from an HIV-positive source with a detectable viral load, or an unknown status but with risk factors

Non-occupational exposures

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• PEP is not needed for:
  • Exposure to stool, urine, tears, saliva, nasal secretions, vomitus, sweat (unless bloody)
  • Oral to oral contact without mucosal damage
  • Contact with intact skin
  • If source was taking PrEP

Post-exposure prophylaxis regimens

Primary regimen

• Truvada (TDF 300 mg / emtricitabine 200 mg) 1 tablet po daily
  • CrCl ≥50
  • Side effects include nausea, headaches, diarrhea, fatigue, renal failure
• Dolutegravir 50 mg 1 tablet po daily
  • Side effects include headache, diarrhea, nausea, fatigue, insomnia
  • If pregnant, replace with raltegravir or darunavir+ritonavir
• Duration 28 days, but can stop early if source is confirmed to be HIV negative

Alternative regimens

• Truvada® 1 tablet daily + raltegravir 400mg twice daily x 28 days
• Truvada® 1 tablet daily + darunavir 800mg daily + ritonavir 100mg daily x 28 days
• Truvada® 1 tablet daily + Prezcobix® (darunavir/cobicistat 800/150mg) 1 tablet daily x 28 days
• Stribild® 1 tablet daily with food x 28 days
• Genvoya® 1 tablet daily with food x 28 days (expert opinion)

Further Reading

• Pocket PEP from St. Michael's Hospital