Immunization of Health Care Workers:more than just the flu

Mary Vearncombe, MD, FRCPC

Medical Microbiologist, Hospital Epidemiologist

Sunnybrook and Women’s College Health Sciences Centre

phone: (416) 480-4243

FAX: (416) 480-6845

e-mail: mary.vearncombe@swchsc.on.ca

HCW Immunization: Background

• HCWs are at risk of exposure to and possible transmission of communicable diseases

- some vaccine preventable• establishing and maintaining immunity is an essential

component of Occupational Health and Infection Prevention and Control programs

• applies to all health care facilities– offices, clinics, acute care, LTC, labs, first responders

• applies to all health care personnel– employees, physicians, students, contract workers, volunteers

HCW Immunization: Background

• immunization protects HCWs, their families, colleagues and patients

• cost containment through prevention of infection

• furloughing susceptibles after exposure

• costs of prophylaxis

• costs of treatment

• absenteeism during acute illness

• disability following illness

• outbreak investigation and control

Disease Categories for HCW Immunization

• active immunization strongly recommended - specific risk for HCWs– i.e., hepatitis B, influenza, measles, mumps, rubella,

varicella

• active ± passive immunization may be indicated in certain circumstances– e.g., hepatitis A, meningococcal disease, TB, pertussis

• immunization recommended for all adults– i.e., tetanus, diphtheria

Occupational Health Assessment

• before placement (after employment)• health inventory:

– immunization status– history: predisposing conditions for

acquisition/transmission of infection– to guide: further immunizations,

post-exposure management– opportunity for adult immunization in

immigrant HCWs• education:

– importance of maintaining personal health– need for annual influenza vaccine

Personnel Immunization

• prevent transmission• prevent work restrictions after exposure• cost-effective compared to:

– treatment of cases– outbreak control

• mandatory vs voluntary programs• screening programs: HBV, MMR, varicella

– documentation of vaccine receipt or immune serology• document refusal

Hepatitis B Vaccine: Pre-ExposurePre-placement:• HB vaccine for all HCWs at risk of exposure to

hepatitis B, i.e., who may have contact with blood, body fluids or sharps

• risk often highest during training period– vaccination should be completed during

training, before clinical exposure• test for anti-HBs 1 month after vaccine series

complete • complete 2nd 3 dose series for primary series non-

responders, then re-test for anti-HBs• if anti-HBs positive, consider immune• if non-immune, counsel regarding exposure

Hepatitis B Vaccine: Pre-Exposure

Ongoing Surveillance:• periodic antibody testing not recommended• booster doses not recommended• HBV unimmunized or non-responders to vaccine

at risk for exposure should be offered annual screening

Hepatitis B Vaccine: Post-Exposure

HBV contact:• response dependent on the vaccination and

antibody status of the HCW• known anti-HBs positive: no further action required• non-responder: HBIG + repeat in 1 month• unvaccinated: HBIG + initiate vaccine• give HBIG ASAP and within 48 hours of exposure• risk for non-immune contact up to 30%

Influenza Vaccine:

NACI Recommended Recipients

“People capable of transmitting influenza to those at high risk for influenza- related complications”

– health care workers: acute care, long term care, home care and outpatient settings

Influenza Vaccine:Why should I be immunized?

You will protect yourself from acquiring “the flu”, or if you do get “the flu” it will be less severe. Influenza vaccine is effective in otherwise healthy adults.– NEJM 333:14 889-893, 1995– JAMA 281:10 908-913, 1999– JAMA 284:13 1655-1663, 2000

Influenza Vaccine:Why should I be immunized?

You will protect your patients from influenza. Vaccination of HCWs reduces illness and mortality of frail elderly patients more effectively than vaccination of patients.– JID 175:1-6, 1997– Lancet 355:8/1/ 2000, 93-97

Influenza Vaccine

Pre-placement:• counsel with regard to implications of transmission

of respiratory viruses (esp influenza) to high risk patients

• counsel with regard to expectation of annual influenza immunization

Ongoing Surveillance:• recommend influenza vaccine annually to all HCWs

before the beginning of the influenza season• utilize strategies to maximize vaccine coverage

– e.g., mobile carts, shift coverage, education, incentives

Influenza Vaccine

Influenza outbreaks:

• immunized personnel may continue to work

• unimmunized personnel working in the affected unit must take antiviral chemoprophylaxis for 2 weeks if they also receive vaccine or until end of outbreak

• unimmunized personnel who refuse chemoprophylaxis should not provide patient care

Measles Vaccine

Pre-placement immunization:• acceptable evidence of immunity:

– positive serology– documented receipt of vaccine

(single vs double dose (NACI))– physician documented clinical measles– born before 1970

• offer vaccine to all non-immune HCWs (MMR)• immunity should be condition of employment

– HCW responsibility to avoid causing harm

Measles VaccinePost-Exposure:

• airborne transmission, highly contagious (masks may not provide protection)

• only immune HCWs should be assigned to patients with measles

• immune HCW: no restriction

• non-immune HCW: exclude from work day 5 to day 21

• immunization of susceptible persons within 72 hours of exposure usually prevents measles

Rubella Vaccine

Pre-placement immunization:• acceptable evidence of immunity:

– positive serology– documented receipt of vaccine

• offer vaccine to all non-immune HCWs (MMR)– goal: prevention of CRS– females and males

• immunity should be condition of employment– HCW responsibility to avoid causing harm

• vaccine contraindicated during pregnancy

Rubella Vaccine

Post-Exposure:• direct face-to-face contact (even if mask worn)• only immune HCWs should be assigned to

patients with rubella• immune HCW: no work restriction• non-immune HCW: exclude from work day 7 - 21

Mumps Vaccine

Pre-placement immunization:• acceptable evidence of immunity:

– positive serology– documented receipt of vaccine– physician documented clinical mumps– born before 1970

• offer vaccine to all non-immune HCWs (MMR)

Mumps Vaccine

Post-Exposure:• droplet transmission, saliva• only immune HCWs should be assigned to patients

with mumps• immune HCW: no restriction• non-immune HCW: exclude from work day 12 - 26• mumps immunization after exposure may not

prevent disease, but will confer protection against future exposures

Varicella Vaccine

Pre-placement:

• ascertain history of varicella /zoster– definite history: assume immune– negative or uncertain: antibody screen

• offer vaccine to HCWs who are non-immune– post-vaccine serology not recommended:

• high efficacy of vaccine• commercially available tests not sufficiently

sensitive

• assign only immune HCWs to patients with varicella / zoster

Varicella Vaccine

Adverse Events:• Post-vaccine rash:

– at injection site: cover and may continue to work– non-injection site: small number of papules/

vesicles and low grade fever - should not work with high-risk patients

• varicelliform rashes within 2 weeks of vaccine are usually due to wild-type virus

Varicella Vaccine

Post-Exposure:• airborne transmission for varicella or disseminated

zoster, or direct contact with lesions– masks may not be effective in preventing

transmission• report exposure to OHS

– immune status unknown: test for antibody– immune: may continue to work– non-immune: exclude from work from 10th day

after the first exposure to the 21st day after the last exposure

– pregnant and non-immune: offer VZIG, exclude until 28th day after last exposure

Varicella Vaccine

Post-Exposure:• management of vaccine recipients ???• vaccine offers 70 - 90% protection against varicella;

95% protection against severe varicella• consider:

– test for immunity; if negative, repeat in 5-6 days (serology insensitive - natural exposure may boost to detectable level), and/or

– observe daily at start of shift for signs/ symptoms of varicella

Varicella Vaccine

Post-exposure vaccine use:• vaccine may prevent or reduce severity of

varicella if given within 3 days (possibly up to 5 days) after exposure

• furlough still required• immunity for subsequent exposures• outbreak control

Meningococcal Disease: Occupational Risk in Clinical HCWs

• There is no risk to HCWs from casual contact with patients with meningococcal disease

• Transmission to HCWs from patients with invasive meningococcal disease may occur after intensive, direct contact where the patient’s respiratory secretions contaminate the HCW’s oral/nasal mucous membranes

Meningococcal Disease:Occupational Risk in Clinical HCWs

• retrospective survey 1982-1996: doctor, nurse, ambulance worker - prolonged contact, airway management Lancet 356:1654-1655, Nov 11, 2000

• pediatrician performed endotracheal intubation ICHE 20:564, Aug 1999

• 4 medical staff after mouth-to-mouth resuscitationJAMA 220:1107-1112, 1972

• ER nurse assisted in intubation, suctioningCDC, MMWR 27:358-363, 1978

• all no barriers (i.e., mask), no prophylaxis

Meningococcal Disease:Occupational Risk in Laboratory Technologists

• 2 technologists MMWR 40:46-47, 1991

• 1 technologist CCDR 20:12-14, 1994 (Quebec)

Biosafety Advisory, Health Canada, Jan, 1992• 3 technologists HIC 28:45-60, April 2001

– 33 cases retrospectively since 1965• 2 technologists MMWR 51:141-144, 2002

– electronic request: 14 cases worldwide in 15 years

Meningococcal Disease:Occupational Risk in Laboratory Technologists

• no identified breaches in laboratory technique

• many cases fatal

• at least one case from a non-invasive isolate

• rate of disease in lab workers dealing with N. meningitidis cultures elevated (US, UK)

Meningococcal Vaccine: NACILaboratory and Healthcare Workers

• routine vaccination of healthcare workers not currently recommended– antibiotic chemoprophylaxis sufficient in high risk

situation• research, industrial and clinical laboratory personnel who

are routinely exposed to N. meningitidis cultures: – MenACYW-Ps recommended– consider MenC-conjugate in addition– vaccine does not replace lab safety standards

Hepatitis A VaccinePre-placement:• routine use of vaccine not recommended

– HCWs not at increased risk

– routine infection control practices prevent transmission

• counsel re prevention of transmission, i.e., hand hygiene; no eating, drinking, in patient care areas

Post-Exposure/Outbreak Control:• give vaccine for post-exposure prophylaxis as soon

as possible and within 7 days of exposure

(not required for routine care of patients with hepatitis A)

Pertussis Vaccine

• pertussis is a frequent cause of cough illness in adolescents and adults; major reservoir of disease and source of transmission

• nosocomial transmission to both patients and HCWs occurs

• prevention of secondary cases difficult as symptoms are non-specific and diagnosis difficult during catarrhal stage

• role of acellular pertussis vaccine in previously immunized HCWs needs evaluation

BCG Vaccine• BCG vaccine does not provide permanent or absolute

protection against TB• loss of tuberculin skin test marker of infection• BCG vaccination of HCWs, including MLTs, may be

considered when all of the following exist:– there is a considerable risk of exposure/ transmission

of tubercle bacilli– a high percentage of strains are drug-resistant– infection control measures have been ineffective or

are not feasible

Tetanus / Diphtheria Vaccine

Pre-placement:

• immunization history

• maintain immunity with booster Td (tetanus/diphtheria toxoid) every 10 years

Polio Vaccine

Pre-placement:• immunization history• HCWs who may have close contact with patients

who may be excreting wild or vaccine poliovirus and laboratory workers handling specimens that may contain polioviruses should be immunized if previously unvaccinated; use inactivated polio vaccine

ROUTINE IMMUNIZING AGENTS STRONGLY RECOMMENDED FOR HEALTH CARE PROVIDERS

Hepatitis B vaccineInfluenza vaccineMeasles/Mumps/Rubella vaccine (MMR)Varicella vaccineTetanus/Diphtheria vaccine (Td)± Polio vaccine

DISEASES FOR WHICH POSTEXPOSUREPROPHYLAXIS MAY BE INDICATED:

Diphtheria RabiesHepatitis A ScabiesHepatitis B Varicella/ZosterMeningococcal disease HIVPertussis Influenza (outbreaks)

Essential References1. Chin, Control of Communicable Diseases Manual, 17th edition, 2000,

American Public Health Association

2. Canadian Immunization Guide, 6th edition, 2002, NACI Recommendations, Health Canada

3. Guide for Infection Control in Healthcare Personnel, 1998, Centers for Disease Control and Prevention, Public Health Service, US Department of Health and Human Services

4. Prevention and Control of Occupational Infections in Health Care, Health Canada, 2002

5. Immunization of Health-Care Workers, 1997 Recommendations of ACIP and HICPAC, Centers for Disease Control and Prevention, Public Health Service, US Department of Health and Human Services