Hepatitis B Prevention in Singapore: Hepatitis B prevention Singapore: Methods to prevent Hepatitis B.
SEXUAL AND OTHER CONTACTS
Partner notification should be performed and documented and the outcome documented at subsequent follow-up. Contact tracing to include any sexual contact or needle sharing partners during the period in which the index case is thought to have been infectious.
The infectious period is from 2 weeks before the onset of jaundice until the patient becomes surface antigen negative. In cases of chronic infection trace contacts as far back as any episode of jaundice or to the time when the infection is thought to have been acquired, this may be impractical for periods of longer than 2 or 3 years.
SCREENING AND PRIMARY PREVENTION
Hepatitis B testing in asymptomatic patients should be considered in MSM, sex workers, injecting drug users, HIV-positive patients, sexual assault victims, needle-stick victims and sexual partners of positive or high-risk patients. If non-immune, consider vaccination. If found to be chronic carriers consider referral for therapy.
With the exception of newborns, serological screening provides a basis for vaccination of an individual without giving an infected individual a false sense of security. Prophylactic vaccination is of no benefit to an individual who already has chronic hepatitis B virus infection; he/she should instead be followed up regularly and treated when indicated. Serological screening for HBsAg and Ab should be done within 6 months pre-vaccination for all except newborn babies [IV, D].
Based on the results of an individual’s serological screening for HBs Ag and Ab, clinicians should the act according to the table below [II, B].
| HBsAg | Anti-HBs | Interpretation | Action to take |
| Non reactive | <10 IU/L | 1. If an individual did not have hepatitis B vaccination before,
• Not immune to hepatitis B Virus. |
1. Administer hepatitis B vaccination |
| 2. If an individual had hepatitis B
vaccinations before Either:
or
did not develop immunity against hepatitis B virus after the primary course of hepatitis B vaccination. NB* |
2. Offer a booster dose of hepatitis B vaccination and check anti-HBs within 3 months
or (to discuss options with patient) Give them another course of (3 injections) of hepatitis B vaccination & recheck anti-HBs within 3 months |
||
| Non Reactive | > 10 IU/L | Immune to hepatitis B | Immunisation is not required |
| Reactive | < 10 IU/L | Presence of hepatitis B virus infection | Clinically assess the patient for liver disease.
To repeat the HBsAg test 6 months later. If HBsAg positive 2 times, 6 months apart, chronic hepatitis B infection confirmed. |
*Under rare circumstances, the emergence of hepatitis B surface mutant (‘s’ mutant) virus can be associated with the absence of HBsAg and a negative or low titre of anti-HBs antibody. For individuals previously vaccinated and with anti-HBs levels < 10 IU/L, consider repeat booster of HBV vaccination or give a second course of HBV vaccination before rechecking the anti-HBs antibody titre [II, C].
For immuno-competent people:
Anti-HBc total should be checked if an otherwise immunocompetent individual fails to seroconvert after 2 courses of HBV vaccinations.
Algorithm for Hepatitis B screening & vaccination – Refer to Annex I
POST VACCINATION TESTING FOR SEROLOGIC RESPONSE
Serologic testing for immunity is not necessary after routine vaccination of adolescents or adults. Testing after vaccination is recommended for persons whose subsequent clinical management depends on knowledge of their immune status e.g. health-care workers, HIV-infected persons and other immunocompromised persons, to determine the need for revaccination and the type of follow-up testing; and sex and needle-sharing partners of HBsAg positive persons to determine the need for revaccination and for other methods to protect themselves from HBV infection.
Persons determined to have anti-HBs levels of < 10 mIU/mL after the primary vaccine series should be revaccinated with a 3-dose series, followed by anti-HBs testing 1-2 months after the third dose.
POST EXPOSURE PROPHYLAXIS (PEP)