The Advisory Committee on Immunization Practices (ACIP), in consultation with the Hospital Infection Control Practices Advisory Committee (HICPAC), has released recommendations concerning the use of certain immunizing agents in health care workers in the United States. These guidelines are intended to help hospital administrators, infection control practitioners, employee health physicians and health care workers optimize infection prevention and control programs. The recommendations were published in the Recommendations and Reports series of the Morbidity and Mortality Weekly Report (December 26, 1997, vol. 46 [RR-18]:1–42).

Because of their contact with patients or infective material from patients, many health care workers are at risk of exposure to and possible transmission of vaccine-preventable diseases. The recommendations apply not only to health care workers in hospitals and health departments but also to those in private physicians' offices, nursing homes, schools and laboratories, and to emergency personnel.

The recommendations for administration of vaccines and other immunobiologic agents to health care workers are divided into the following three disease categories (see table):

• Those for which active immunization is strongly recommended because of special risk for health care workers (i.e., hepatitis B, influenza, measles, mumps, rubella and varicella).

• Those for which active and/or passive immunization of health care workers may be indicated in certain circumstances (i.e., tuberculosis, hepatitis A, meningococcal disease, typhoid fever and vaccinia) or in the future (i.e., pertussis).

• Those for which immunization of all adults is recommended (i.e., tetanus, diphtheria and pneumococcal disease).

Immunization That Is Strongly Recommended

ACIP strongly recommends that all health care workers be vaccinated against (or have documented immunity to) hepatitis B, influenza, measles, mumps, rubella and varicella.

Hepatitis B

Any health care worker who performs tasks involving contact with blood, blood-contaminated body fluids, other body fluids or sharps should be vaccinated. Hepatitis B vaccine should be administered by the intramuscular route in the deltoid muscle with a needle 1.0 to 1.5 inches long.

One to two months after completion of the three-dose vaccination series, health care workers who have contact with patients or blood and are at ongoing risk for injuries with sharp instruments or needle sticks should be tested for antibody to hepatitis B surface antigen (anti-HBs). Persons who do not respond to the primary vaccine series should complete a second three-dose vaccine series or be evaluated to determine if they are positive to hepatitis B surface antigens (HBsAg). Revaccinated persons should be retested. Persons who prove to be HBsAg-positive should be counseled accordingly. Primary non-responders to vaccination who are HBsAg-negative should be considered susceptible to hepatitis B virus infection and should be counseled regarding precautions to prevent hepatitis B virus infection and the need to obtain hepatitis B immune globulin prophylaxis for any known or probable parenteral exposure to HBsAg-positive blood. Booster doses of hepatitis B vaccine are not considered necessary, and periodic serologic testing to monitor antibody concentrations after completion of the vaccine series is not recommended.

Influenza

The following health care workers should be vaccinated against influenza in the fall of each year:

• Persons who take care of patients at high risk for complications of influenza (whether the care is provided at home or in a health care facility).

• Persons 65 years of age and older.

• Persons with certain chronic medical conditions.

• Pregnant women who will be in the second or third trimester of pregnancy during the influenza season.

Measles, Mumps and Rubella

Because any health care worker who is susceptible can, if exposed, contract and transmit measles or rubella, all medical institutions should ensure that those who work within their facilities are immune to measles and rubella. Immunity to mumps is also very desirable. In addition, health care workers have a responsibility to avoid causing harm to patients by preventing transmission of these diseases.

Measles-mumps-rubella (MMR) trivalent vaccine is the vaccine of choice. MMR or its component vaccines should not be administered to women who are pregnant. Women should be counseled to avoid pregnancy for 30 days after administration of monovalent measles or mumps vaccines and for three months after administration of MMR or other rubella-containing vaccines. If a pregnant woman is vaccinated or if a woman becomes pregnant within three months after vaccination, she should be counseled about the theoretical basis of concern for the fetus, but MMR vaccination during pregnancy should not ordinarily be a reason to consider termination of pregnancy. Measles vaccine is not recommended for HIV-infected persons with evidence of severe immunosuppression.

Varicella

All health care workers should ensure that they are immune to varicella. Immunization is particularly recommended for susceptible health care workers who have close contact with persons at high risk for serious complications. Routine postvaccination testing of health care workers for antibodies to varicella is not recommended.

Hospitals should develop guidelines for management of vaccinated health care workers who are exposed to natural varicella. Seroconversion after varicella vaccination does not always result in full protection against disease. Therefore, the following measures should be considered: serologic testing for varicella antibody immediately after varicella zoster virus exposure, retesting five to six days later, and possible furlough or reassignment of personnel who do not have detectable varicella antibody. It is not known if postexposure vaccination protects adults.

Hospitals also should have guidelines for managing health care workers after varicella vaccination because of the risk for transmission of vaccine virus.

Recommendations are also discussed for hepatitis C and other parenterally transmitted non-A, non-B hepatitis viruses; tuberculosis, hepatitis A, meningococcal disease, pertussis, typhoid, vaccinia, tetanus and diphtheria, and pneumococcal disease. ACIP does not recommend routine immunization of health care workers against tuberculosis, hepatitis A, pertussis, meningococcal disease, typhoid fever or vaccinia. However, immunoprophylaxis for these diseases may be indicated for health care workers in certain circumstances. There is also a discussion on immunization of immunocompromised health care workers.

A section on other considerations in vaccination of health care workers includes immunization records, catchup vaccination programs, work restrictions for susceptible workers after exposure, outbreak control and vaccines indicated for foreign travel.