Transcript Specific design for occupational health service in the
Specific design for occupational health service in the hospital
Immunization in HCW
Pitchaya Phakthongsuk, MD, Ph.D.
Occupational health unit, Community Medicine Dpt., Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
Factors considering for vaccination program design
• • • • • •
Efficacy and safety Epidemiology of selected preventable vaccine
–surveillance of seroprevalence, antigenic drift
Effective
–adequate vaccine coverage
Economic
–financially
Sustainable
– operating at funding levels that are realistically in long term
Attractive
–offering benefits to target populations, donors, and vaccine suppliers
Strongly recommended immunization
Hepatitis B MMR Varicella Influenza
The Advisory Committee on Immunization Practices -ACIP and the Hospital Infection Control Practices Advisory Committee –HICPAC
(MMWR 1997;46(RR-18):1-42)
HBV –high efficacy 90%
(vaccine 2002;20:3695-701
)
Prevalence of Non responder after immunization
(BMC Infect Dis 2007;7:120 doi: 10.1186/1471-2334-7-120)
Post-vaccination testing is indicated
• Non-responder 10%
( MMWR 2007:46;1-42)
– anti-HBs <10 mIU/mL after 3 doses vaccine series – and complete a 2 nd 3-dose vaccine series – or evaluated HBsAg-positive. .
• Persons who do not respond to an initial 3 dose => 30-50% chance in 2 nd 3-dose series
(Clin Infect Dis
1998
;26:566 –71)
Periodic screening and Booster –no need
immunological antibody last memory for at least immunocompetent individuals => 15 anamnestic years in
(lancet 2000:355;561-5)
–
periodic selorogic screening => no need; 60% lose anti-HBs in 12 yrs but still protective
(Pediatric 1992;90:170-3; vaccine 2007;25:6958-64)
–
booster of HB vaccine -no need in immunocompetent individuals who have responded to a primary course; evidence on persisting anti-HBs and /or in vitro B-cell stimulation /or an anamnestic response
(panel of expert in Lancet 2000; 355: 561 –65)
Carrier Natural immuned Isolated antiHBc Protective anti-HBs antiHBs <10 mIU None immune infection Infection?
Seroprevalence in HCW at Institute of Neurology
(J Med Assoc Thai 2007;90:1536-45)
Prevaccination testing for cost-effectiveness
Step 1. anti-HBc and anti-HBs Step 2. HBsAg antiHBc neg pos neg pos pos antiHBs pos pos neg neg neg HBsAg no need neg no need pos neg immuned due to vaccine immune due to natural infection HB vaccine 1 dose given and see anamnestic response ; if not ‘no immune’ continued 2 doses infection resolved infection or occult HB infection or false positive
HBV:
post exposure
(MMWR 2007;50:1-42)
MMR
• Nosocomial infection is common • Transmission period – Measles: 4 d before rash until 4 d after rash – Mump: 1-4 d before until 7 d after symptom start – Rubella: 5 d before rash until 6 d after rash; but in throat, 14 d after rash • Efficacy: 95%; Immune prolonged up to 15 years after 2 doses of MMR (
Vaccine 2000;18:3106-112)
Seroprevalence MMR in Thai population
•
1989 -43% pregnant women had Rubella Ab
•
1991 -67% of HCW in Srinagarind hospital had Rubella Ab => cost-benefit analysis limited laboratory facilities, repeat immunization without prior screening for antibody is cheaper
(Srinagarind Hosp Med J 1991;6:19-27)
•74.67% pregnant women had Rubella Ab •Cost of screening using ELISA technique was 350 baht/case so repeating rubella immunization for all high school females would be more cost effective and certain protection’
(J Med Assoc Thai 2005;88:457-9)
MMR
•
Prevac test: not cost effective (vaccine is safe for immuned person)
•
Postvac test: not need but cold chain should be guaranteed
•
Note: -contraindication in pregnancy and immunocompromized host -avoid pregnancy in 30 d after measles, 90 d after MMR -anaphylaxis after gelatin ingestion or neomycin
MMR
Persons considered immuned if 1. Physician diagnosed of measles or mump (not rubella) 2. Positive serology but not recommended serologic screening in HCW 3. Vaccination Hx: 2 doses of live measles and mumps separated by ≥ 28 days apart, and at least 1 dose of live rubella vaccine
Influenza virus
• Nosocomial transmission during outbreak; found year round, highest in rainy season • Influenza A (H1N1, H3N2 etc.) and B => antigenic drift • Administration: 0.5 ml IM once yearly with current virus • Efficacy: 70-90% when the vaccine and circulating viruses are well-matched (
MMWR 2006;55:1-15)
Influenza virus
•Recommendation in Thailand is not strong due to –cost –new influenza virus variants due to frequent antigenic drift from point mutations
(MMWR 2007;56 (RR-56):1-60)
•may consider immunize before rainy season for HCWs who work in chronic facilities; who with high risk medical conditions
Influenza virus
Personnel at risk during avian flu outbreak • All persons in contact with poultry or poultry farms suspected of H5N1 , esp. at mass slaughter of poultry; people living and working on poultry farms where H5N1 suspected or reported.
• Health care workers involved in the daily care or confirmed human cases of influenza H5N1 . of known • Given sufficient supplies of vaccine, health care workers in emergency care facilities in areas where there is confirmed occurrence of influenza H5N1 in birds.
Varicella-Zoster virus
• Very common nosocomial infection • High risk –pregnancy, immunodeficiency, premature, adults • Transmission period: 1 or 2 days before rash appears until all the blisters dried up, usually 4-5 d • Administration: SC, >13 yrs 2 dose (6-10 wk interval), 12 mo-12 yr 1 dose • Efficacy: 70-90%,> 95% for severe VZV (
Am J Infect Control
1989;17:26 –30)
Varicella-Zoster virus
• Prevac serologic screening –may cost effective – 70-90% of adults who do not remember having chickenpox actually have protection in their blood when tested – All HCW, medical and nurse students without evidence of immunity; 29% young adults were susceptible
(Southeast Asian J Trop Med Public Health 1985;16:414-20)
• Postvac testing is not recommended => 1 dose seroconversion 94.9% and 100% in 2 dose
(Southeast Asian J Trop Med Public Health 2004;35:697-701)
Varicella-Zoster virus
•
Postexposure:
– VZV vaccine within 3 days, and possibly up to 5 days
(MMWR 1999;48(RR06);1-5)
•
Precautions:
– Do not become pregnant for 3 receiving VZV months after – History of anaphylactic reaction of neomycin or gelatin
Other vaccines may be indicated/ not indicated
Hepatitis A Typhoid Meningoccoal Tdap, dT BCG Hib
Tuberculosis
• Uncontrolled infection in hospital • In 2006, Thailand ranked 18th on the list of high-burden countries; incidence 135:10 5 ; an explosive HIV epidemic in the 1990s => sudden increase in TB cases. 15% of all TB cases was HIV-associated ใ
(Bull World Health Org 2007;85:586 –592)
Tuberculosis
• No effective vaccine • Nearly all Thais => BCG and environmental exposed; BCG at birth can not prevent TB, but help prevent miliary and TB meningitis in children
Tuberculosis –How to control
•Early detection and prompt Tx •
source control:
Case isolation,Local ventilation with HEPA filter, mask for the patient •
Path control:
general ventilation, germicidal ultraviolet lamps •
Receiver control:
respirators for HCW, 2 step PPD test (to prevent Booster phenomenon), if +ve (wheal >10 mm) chest X-ray
Hepatitis A
• Minimal risk in general HCW • More than 80% of Thai adults ≥ 26 years were anti-HAV positive
(SEA J Trop Med Pub Health 2004;35:416-20)
=> not recommend for routine immunization • Considered in HCWs in microbiology lab.
Meningoccocal
• Vaccine only for gr.A C Y and W-135 but not gr.B (most common in Thailand) • Meningoccocal vaccine -Not recommend • Post exposure prophylaxis: Rifampicin (600) bid * 2 d, ciprofloxacin (500-750) OD, ceftriaxone 250 mg IM
( MMWR 2005;54(RR 7);16-7)
typhoid
• Uncommon in Thailand now • Considered in microbiology lab. Personnel who work with Samonella typhi • Efficacy: – Whole cell 73% (Subcuteneous 2 doses); oral Ty21a 51% (3 doses) every; Vi (intramuscular 1 dose) 55%
(BMJ 1998;316:110-116)
– Low efficacy – Now nontyphi, nonparatyphi samonella are emerging problem in Thailand
Tdap, dT
• For Diptheria, Pertussis -HCW as reservoir for infants (adults have mild symptoms) but infants are at risk for serious dz.
• Tetanus –seroprevalence 99.7% of Thai population
(Asia Pac J Allergy Immunol 2007;25:219-23)
• Postexposure prophylaxis for Diptheria, Pertussis with antibiotic is recommended • Tdap may be considered in area with epidemic outbreak of Diptheria and Pertussis, e.g., migrant workers area
HIB Haemophilus influenza type b
Clin Microb Rev 2000;13:302-17
Optimal vaccine in Asia due to very low prevalence compared to other part of the world
What should be the program for HCW?
Hepatitis B
MMR
Varicella
Influenza
Hepatitis A Typhoid Meningoccoal Tdap, dT BCG Hib