Post-exposure Prophylaxis Hepatitis B

Post-exposure prophylaxis (PEP) is treatment that can be used after possible exposure to the hepatitis B virus through sex, drug injecting equipment or injury such as needle stick injury. PEP is given to decrease the risk of infection with the hepatitis B virus. It does not reduce the risk of other sexually transmissible infections or infection with other blood-borne viruses such as hepatitis C.

The exposed person can be treated with a single dose of hepatitis B immunoglobulin and three doses of hepatitis B vaccine over six months. However, if the exposed person has previously been vaccinated for hepatitis B, and had a blood test documenting a response to the vaccine, then no treatment is necessary.

Post-exposure prophylaxis can be used in emergency situations where there has been a failure in usual precautions and there may be a risk of exposure to hepatitis B. Examples are:

  • occupational exposure for health care workers
  • broken condom
  • sexual assault
  • unprotected sex
  • sharing injecting equipment with a person infected with hepatitis B
  • needle
  • stick injury in a public place (although this risk is extremely low).

What to do

The best ways to avoid infection with the hepatitis B virus and other blood-borne and sexually transmissible infections include:

  • safe sex, including consistent and correct use of condoms
  • not injecting drugs
  • if you do inject drugs, always use sterile equipment and don't share any equipment
  • get vaccinated - hepatitis B vaccination provides long term protection.

If there has been an incident in which a person may have been exposed to the hepatitis B virus, they should go to their local doctor, family planning clinic, sexual health clinic or local public hospital as soon as possible, preferably within 24 hours. The longer a person waits to be treated, the less effective PEP may become.

It is natural for people in this situation to be very anxious. The treating doctor will provide information and support.

The doctor will also assess the risk of exposure. This depends on what is known about the person or persons who are the source of possible infection. The doctor will want to determine:

  • is the person known to be infected with hepatitis B?
  • is the person in a high risk group for infection with hepatitis B?
  • can the person be contacted?
  • will the person consent to testing?

At the first visit to the doctor or clinic, blood tests may be done. There are no tests which can show whether a person has been infected with hepatitis B or any other infection from an exposure within the past couple of days. These first blood tests are done to check whether that person has any sign of previous infection with hepatitis B, or prior immunity to hepatitis B virus.

Tests will be repeated at six weeks, three months and six months. After infection with hepatitis B, it may take some time for the infection to show up in blood tests. This is called the window period, which is up to six months for hepatitis B. A person cannot be sure there is no infection until the test at six months is negative.

If there is a risk of exposure to hepatitis B virus, PEP for hepatitis B would be recommended.

The risk of infection with hepatitis C virus and sexually transmissible infections should also be considered. Tests can be done if necessary.

Until tests and follow-up are completed:

  • do not donate blood, breast milk or semen
  • have safe sex
  • do not share injecting drug equipment
  • seek advice from the doctor about pregnancy and breast feeding.

If there is a risk of pregnancy, women should ask the doctor or health worker about emergency contraception.

Hepatitis B Vaccination

Blood tests can show whether a person has prior immunity to hepatitis B virus. This could be from past infection or from an earlier vaccination. If there is no immunity, an injection of immunoglobulin can be given. This provides protection against recent exposure to hepatitis B virus. Hepatitis B immunoglobulin does not provide long term protection against hepatitis B virus.

Hepatitis B vaccination is recommended as safe and effective long term protection against hepatitis B virus. It is given as three injections over six months.

Other resources: 
Help and assistance: 

For more information about post-exposure prophylaxis, people can talk to: