Needlestick transmission of blood-borne viruses Flashcards
How to prevent Hep B infection from needlestick in HCW
Vaccination of non-responders or non-vaccinated
PEP - vaccination or HBIg
How to prevent Hep B infection from needlestick in HCW
Vaccination of non-responders or non-vaccinated
PEP - vaccination or HBIg
What type of Hep B positive patient is the most infectious?
HepB E Ag positive.
Reduced risk if Anti-E positive and low levels of HBV DNA
What does a HBV vaccination consist of?
Purified surface Ag
Requires x 3 doses
What is the definition of a non-response to HBV vaccination? What are its implications?
How many adults are HBV vaccination non-responders?
5-10%
What type of Hep B positive patient is the most infectious?
HepB E Ag positive.
Reduced risk if Anti-E positive and low levels of HBV DNA
What does a HBV vaccination consist of?
Purified surface Ag
Requires x 3 doses
What should the response be to Hep B vaccination?
Generation of anti- HBs
What is the definition of a non-response to HBV vaccination? What are its implications?
0-10 iu
No hep b protection
How many adults are HBV vaccination non-responders?
5-10%
What is the definition of a hypo-response/sub-optimal responders to HBV vaccination? What are its implications?
10-100 iu/l 6-10 weeks after completion of vaccination schedule.
? protected against HBV infection or not
USA and Europe consider protective.
‘Seroconversion’
How many adults are HBV vaccination sub-optimal responders?
5-10% adults
What is the definition of an optimal response to HBV vaccination? What are its implications?
> 100 iu/l 6-10 weeks after completion of 3-dose vaccination schedule
Protected against HBV infection
‘Seroprotection’
What can be done to increase protection of HBV vaccination non-responders?
Repeat course of vaccine and re-test anti-HBs (Complete course of 6)
What can be done to increase protection of HBV vaccination in poor responders
Booster dose (x 4 in total)
How are HCWs protected against HCV?
Treatment of acute infection within 3-6 months - very high clearance rates
Encourage reporting of needle stick exposures/mucosal splash
Monitor for evidence of HCV infection
Treat
Why is the policy for HBV vaccination in childhood?
Vaccine response linked to age - better response vaccination people at younger age.
Reduce the no. of sub-optimal/non-responders seen.
What is looked at to assess significance of exposure to HBV?
Route - percutaneous, mucocutaneous, sexual
Source material - blood > other bodily fluids
How is an exposure incident managed?
Seek advice
Routine testing of needle stick source - need consent from person giving blood
Risk assess source and recipient: - what type of needle? where was the stick?
- HBV consider post exposure management
- HCV monitoring
- HIV consider PEP
What intervention is taken for a HCW with exposure to HCV?
Monitoring and early diagnosis.
No HCV vaccine
What prevention methods can be taken for HCV
None, no vaccine = no passive immunisation
How are HCWs protected against HCV?
Treatment of acute infection within 3-6 months - very high clearance rates
Encourage reporting of needlestick exposures/mucosal splash
Monitor for evidence of HCV infection
Treat
What are the stages of HCV monitoring?
6 weeks = HCV PCR
12 weeks = HCV PCR + anti HCV serology
6 months = HCV PCR + anti-HCV serology again
What treatment is offered to prevent HIV infection post exposure?
PEP antiviral triple therapy offered if needle stick known HIV positive or not known but high risk.
NRTI, NNRTI and PI 4 weeks.
How is an exposure incident managed?
Seek advice
Routine testing of needle stick source - need consent from person giving blood
Risk assess source and recipient: - what type of needle? where was the stick?
- HBV consider post exposure management
HCV monitoring
HIV consider PEP
Exposure prone procedures are?
those where there is a risk that injury to the worker may result in the exposure of the patients open tissues to the blood of the worker.
Latest/current guidelines of HBV and HCWs
anti-HBe +ve HCWs measure viral load:
- >10^3 copies/ml = banned from EPPs
-
Examples of EPP
All surgery
All dentistry
Repair of episiotomy
instrumental delivery
Examples of non-EPP
Taking blood setting up IV lines Minor surface suturing Incision of abscesses Uncomplicated endoscopy Normal vaginal delivery
Can HBV carriers/HBsAg pos be anti-HBs?
Yes.
Usually of low tire eg. 10-100 iu/l and non-neutralising
What order of testing/vaccination for HCV is carried out on HCWs in order to catch HCV carriers before vaccination?
sAg testing
If neg:
Vaccine,
test anti-HBs response (confidence in protection)
Why can testing e markers (eAg +ve) be misleading in HCWs?
Assumed if HBeAg +ve = highly infectious
But can have virus with pre-core mutants = unable to synthesise e antigen (HBeAg -ve) but highly replicative virus? - misleading as may be highly infectious and at at high risk of chronic liver disease
Latest/current guidelines of HBV and HCWs
anti-HBe +ve HCWs measure viral load:
- >10^3 copies/ml = banned from EPPs
-
Which antivirals are used to reduce infectivity but licensed to reduce liver damage?
Tenefovir and Entecavir (dec risk of resistance vs lamivudine)
What actions are in place to protect patients from HCV from health care workers?
Known HCV RNA +ve workers = out
Current HCWs doing EPPs encouraged to be tested if risk factors i.e. needlestick
For HCWs entering EPP specialities test for HCV infection - doverts HCV pos trainees away from EPP specialities.
Standard health checks offered to new employees/HCWs returning to NHS/HCWs performing EPPs for the first time/students
HBV vaccine
testing for HCV
Testing for HIV
without affecting employment or training….
Additional health checks offered to new NHS HCWs doing EPPs
Test for HBsAg, then vaccinate and test for anti-hsb
Test for anti-HCV
Test for anti-HIV
Are you allowed to operate if you are HIV pos?
No
