Immunizations aren't a shot in the dark; new CDC guidelines boost urgency

Hospitals urged to develop HCW immunization policies

In an effort to promote comprehensive and consistent immunization programs for health care workers nationwide, the U.S. Centers for Disease Control and Prevention has issued guidelines for the use of vaccines in three categories. The document also updates recommendations for hepatitis B postvaccination testing and postexposure prophylaxis for certain workers, as well as for determining measles immunity.1

HCWs, from physicians and nurses to laboratory technicians and hospital volunteers, are at risk for exposure to vaccine-preventable diseases from contact with patients or infective material from patients. Maintaining immunity is an "essential part" of infection prevention and control programs for HCWs. Immunization programs can substantially reduce both the numbers of susceptible hospital HCWs and the risks of disease transmission to patients, the guidelines note.

The CDC encourages all medical facilities that provide direct patient care to formulate a comprehensive immunization policy for HCWs based on the guidelines and previously published recommendations for optimal use of immunizing agents. (See Table 1, p. 42.) The document combines recommendations from the Advisory Committee on Immunization Practices (ACIP) previously published separately with the new hepatitis B information. It was prepared in consultation with the Hospital Infection Control Practices Advisory Committee (HICPAC) and is consistent with current HICPAC guidelines.

Vaccine-preventable diseases are grouped into three categories:

· those for which active immunization is strongly recommended because of special risks for HCWs - hepatitis B, influenza, measles, mumps, rubella, and varicella;

· those for which active and/or passive immunization may be indicated in certain circumstances - tuberculosis, hepatitis A, meningococcal disease, pertussis, typhoid fever, and vaccinia;

· those for which immunization of all adults is recommended - diphtheria, tetanus, and pneumococcal disease.

The guidelines also discuss recommendations for immunizing HCWs who are immune-compromised due to HIV infection (see related story, p. 43) or other conditions, or who are pregnant. (See Table 4, p. 45.) In addition, appropriate work restrictions for HCWs exposed to or infected with certain vaccine-preventable diseases are outlined. (See Table 5, inserted in this issue.)

While the CDC encourages employee health managers to vaccinate all susceptible employees, the agency has not determined levels of acceptable compliance. In 1993, the agency surveyed more than 800 hospitals and found poor compliance across the board with then-current recommendations for HCW vaccinations. (See related story in Hospital Employee Health, November 1994, pp. 146-148.) Results of the unpublished survey showed that about 80% of hospitals had written vaccination policies, but those policies differed widely regarding which vaccines were included in immunization programs. No hospital had a comprehensive vaccination program for HCWs.

"Good compliance is not defined, but there has been discussion that the year 2000 health objectives should include vaccination levels for health care workers," says Raymond A. Strikas, MD, a medical epidemiologist in the CDC's National Immunization Program and co-author of the immunization guidelines.

"In 1993, hospitals acknowledged that they weren't doing a real good job in terms of compliance with published guidelines from the Public Health Service. It means those guidelines have not been a priority for them, but we think they should be," Strikas says. "A reasonable level of success might be 60% [HCW compliance with some vaccinations], but perhaps 70% or better for hepatitis B due to Occupational Safety and Health Administration regulations" that mandate offering HBV vaccine.

While 60% to 70% may be considered an acceptable goal, 100% would be better, says Kathleen Van Doren, RN, BSN, COHN-S, executive president of the Reston, VA-based Association of Occupational Health Professionals in Healthcare. However, Van Doren says full compliance probably will never be achieved unless immunizations are tied to employment, either as a condition of being hired, getting paid, or continuing to work.

Requiring applicants to be vaccinated before they would be hired raises administrative concerns about costs associated with vaccinating people who aren't employees, and the idea of refusing to hand over a paycheck to an unvaccinated worker was foiled when direct bank deposit became popular, she notes.

"The only way to ensure compliance is to get cooperation from managers and the human resources department for suspensions of those who avoid vaccination," says Van Doren, who also is an employee health nurse at Good Samaritan Hospital and employee health coordinator at Children's Hospital Medical Center, both in Cincinnati. "That gets employees in your office very quickly."

Without that kind of leverage, obtaining compliance can be difficult. "When they come in for their preplacement physical exams, I tell them working in a hospital is hazardous to their health. I explain the importance of all the immunizations and tell them their compliance will help me do my job, will help keep them healthy, and will help prevent disease transmission to patients. They smile and nod and say they understand, and then I find myself writing them their second and third and fourth reminder notice," she says.

A national adult immunization expert agrees that more active efforts are needed to boost vaccination rates among HCWs. While compliance with immunization programs varies by hospital, Gregory A. Poland, MD, chair of the National Coalition for Adult Immunization in Bethesda, MD, says in general, it's "miserable."

Most hospitals make only "passive" attempts to vaccinate workers, while at the very least, they should offer all recommended immunizations in the same manner as they do hepatitis B vaccine, which OSHA requires to be offered to all employees who risk exposure, says Poland, who also is chief of the Mayo Vaccine Research Group and associate professor of medicine at the Mayo Clinic and Foundation in Rochester, MN. A "passive" vaccination program is one that does not enforce strict vaccination policies.

"If I had my way, the program I'd run would be like the one for hepatitis B. We would encourage and record for everybody that they get the vaccination or they sign a declination statement," he says.

Poland advocates active programs to immunize workers against varicella, measles, mumps, rubella, and influenza, as well as hepatitis B, and says he would support a federal regulation requiring HCW immunity against those diseases.

While CDC guidelines are voluntary, Strikas says he hopes bringing together previously published and new recommendations in the form of comprehensive, formal guidelines under the aegis of ACIP "will get more attention."

While many of the guidelines have been compiled from published sources, new information not released elsewhere is included in the hepatitis B section. (For specific guidelines related to HCW immunization for each vaccine-preventable disease, see Table 2, inserted in this issue.)

Although previous CDC recommendations allowed hepatitis B postvaccination testing up to six months postvaccination, the guidelines now state that HCWs who have contact with patients or blood and are at risk for sharps injuries should be tested for antibody to hepa titis B surface antigen (HBsAg) one to two months after completion of the three-dose vaccination series.

"Postvaccination testing applies to those health care workers who are likely to have exposures that would require evaluation for postexposure prophylaxis," says Miriam J. Alter, PhD, MPH, chief of the epidemiology section in the CDC's hepatitis branch and author of the guidelines' hepatitis portions.

People who do not respond to the primary vaccine series should complete a second three-dose series or be evaluated to determine if they are HBsAg-positive. Revaccinated workers should be retested following completion of the second vaccine series. Those who prove to be HBsAg-positive should be counseled appropriately. Primary nonresponders who are HBsAg-negative should be considered susceptible to HBV infection and counseled about precautions to prevent infection and the need for hepatitis B immune globulin (HBIG) prophylaxis for known or probable exposures to HBsAg-positive blood.

Postexposure prophylaxis should be considered for any percutaneous, mucous membrane, or ocular blood exposure and is determined by the source's HBsAg status and the vaccination and vaccine-response status of the exposed worker. (See Table 3, above.)

Another new recommendation is that health care workers who responded to the primary vaccine series and are exposed to an HBsAg-positive source do not need prophylaxis.

"They do not need to be tested, and they do not need any prophylaxis, even if they're anti-HBs and their antibody has waned below detectable levels," Alter says. "Previously, we recommended a booster dose. Now we have finally made that recommendation consistent with what we know to be true - that these individuals are protected."

The guidelines explain that while vaccine-induced antibodies to HBV decline gradually over time, with up to 60% of people who initially responded to vaccination losing detectable antibodies over 12 years, vaccine-induced immunity continues to prevent clinical disease or detectable viremic HBV infection. Therefore, booster doses are considered unnecessary. (For more information on booster doses, as well as on the declining risk of HBV infection among HCWs, see story, p. 51.)

Prevaccination serologic screening for previous infection also is not recommended for workers being vaccinated unless the hospital considers it cost-effective.

Another modification of familiar guidelines relates to recommendations for measles-mumps-rubella (MMR) vaccination. Being born before 1957 generally has been considered acceptable evidence of measles immunity; however, the new guidelines point to serologic studies of hospital workers that indicate 5% to 9% of those born before 1957 are not immune to measles. In addition, unpublished CDC data show that during the 1985-1992 period, 27% of all measles cases among HCWs occurred in people born before 1957.

Therefore, the CDC now advises health care facilities to consider recommending a dose of MMR vaccine to unvaccinated workers born before 1957 who are in either of the following categories:

· those who do not have a history of measles disease or laboratory evidence of measles immunity;

· those who lack laboratory evidence of rubella immunity.

However, Strikas suggests that the highest priority group to vaccinate at hospitals with "limited resources" is workers who were born in 1957 or later "because the later you were born, the more likely you are to be nonimmune if you haven't been vaccinated.

"But if at all possible, vaccinate the other people, too," he says. "You might find it beneficial to screen them because the majority may be immune, and you can save yourself some money."

Workers born in 1957 or later can be con sidered immune to measles, mumps, or rubella only if they have documentation of one of the following:

· physician-diagnosed measles or mumps disease;

· laboratory evidence of measles, mumps, or rubella immunity;

· appropriate vaccination against measles, mumps, and rubella.

"Rubella vaccination or laboratory evidence of rubella immunity is particularly important for female HCWs born before 1957 who can become pregnant," the guidelines note. Rubella can occur in unvaccinated people born before 1957, and congenital rubella syndrome can occur in offspring of women infected during pregnancy.

For other strongly recommended immunizations, the guidelines state the following:

· Influenza.

To reduce staff illnesses and absenteeism and to minimize transmission to patients, vaccinate these workers in the fall of each year:

- those who attend patients at high risk for influenza complications, whether care is provided at home or in a health care facility;

- those ages 65 or older;

- those with certain chronic medical conditions (e.g., chronic cardiovascular or pulmon- ary disorders, diabetes, renal dysfunction, hemoglobinopathies, or immunosuppression including HIV infection);

- pregnant women who will be in the second or third trimester during influenza season.

· Varicella.

Immunization is particularly recommended for susceptible HCWs who have close contact with patients at high risk for serious complications, such as:

- premature infants born to susceptible mothers;

- infants born at less than 28 weeks gestation or who weigh 1,000 grams or less at birth, regardless of maternal immune status;

- pregnant women;

- immunocompromised patients.

Serologic screening for varicella immunity need not be done unless it is considered cost-effective. Routine postvaccination testing for varicella antibodies is not recommended because at least 90% of vaccinees are seropositive after the second vaccine dose.

Hospitals should develop guidelines for managing vaccinated HCWs who are exposed to natural varicella. Seroconversion after vaccination does not always fully protect against disease. These measures should be considered for workers who are exposed to natural varicella:

- serological testing for varicella antibody immediately after exposure;

- retesting five to six days later to determine if an anamnestic response is present;

- possible furlough or reassignment of workers without detectable varicella antibody.

Hospitals also should develop guidelines for managing workers postvaccination due to the risk of vaccine virus transmission. Facilities might consider precautions for HCWs who develop a vaccination-related rash and for other vaccinated workers who will have contact with susceptible patients at high risk for serious complications. (For a story on hospitals' considerations in developing a varicella vaccination program, see Hospital Employee Health, October 1997, pp. 109-113.)

[Editor's note: For more information on recommendations in all three immunization categories, obtain a copy of the complete guidelines. Contact: Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402-9325. Telephone: (202) 512-1800. The document is also available on the World Wide Web at http://www. cdc.gov. Click on MMWR, then click on Recom-mendations and Reports.]

Reference

1. Centers for Disease Control and Prevention. Immunization of health-care workers: Recommendations of the Advisory Committee on Immunization Practices (ACIP) and the Hospital Infection Control Practices Advisory Committee (HICPAC). MMWR 1997; 46(No. RR-18):1-42.