1. STDs
2. Hep B
3. Prevention

Hepatitis B Prevention Singapore | Shim Clinic

Hepatitis B prevention Singapore: Methods to prevent Hepatitis B.

• Before exposure – Hepatitis B vaccination
• During sex – Safe sex with condoms.
• After exposure – Hepatitis B immunoglobulin and Hepatitis B vaccination. Antivirals.

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].

*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:

• With low risk of acquiring HBV and
• Who have completed their HB vaccination and
• Who had previously demonstrated immunity to HBV after vaccination, there is no need to check for immunity again or receive booster injections if their anti-HBs is < 10 IU/L later on [II, C].

Anti-HBc total should be checked if an otherwise immunocompetent individual fails to seroconvert after 2 courses of HBV vaccinations.

1. HBsAg negative, anti-HBs < 10 IU/L, anti-HBc positive – These individuals may have HBV infection with low viral load and an undetectable level of HBsAg. Refer to specialists for further workup.
2. HBsAg negative, anti-HBs < 10 IU/L, anti-HBc negative – Consider repeat vaccination with pre-S vaccine or other 3rd generation vaccine, if available, especially if the individuals belong to the high-risk group. They should be advised against high risk behaviour, which may expose them to Hepatitis B infections, and counselled about PEP with HBIG if they do sustain high risk exposure [III, D].

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)

• Specific hepatitis B immunoglobulin 500 i.u. intramuscularly (HBIG) may be administered to a nonimmune contact after a single unprotected sexual exposure or parenteral exposure/needlestick injury if the donor is known to be infectious. This works best within 48 hours and is of no use after more than seven days [Ib, A]
• An accelerated course of recombinant vaccine should be offered to those given HBIG plus all sexual and household contacts (at 0, 7 and 21 days or 0, 1, 2 months with a booster at 12 months in either course) [Ib, A]. Vaccination theoretically will provide some protection from disease when started up to six weeks after exposure
• Avoid sexual contact, especially unprotected penetrative sex, until vaccination has been successful (antiHBs titres >10i.u./l.)

References

• Hepatitis B prevention @ Wikipedia