Special Report
Xenotransplant IC included in PHS draft guidelines
Draft xenotransplant guidelines issued by the Public Health Service include recommendations for hospital infection control and occupational health programs to protect patients receiving animal organs or tissues and the health care workers caring for them.1 Highlights of the recommendations are summarized as follows:
General measures: The xenotransplant team should include individuals such as the surgeon, infectious disease physician, veterinarian, transplant immunologist, infection control specialist, and clinical microbiologist. The clinical center should be associated with an accredited virology and microbiology laboratory. Protocols, which are subject to review and approval by the Food and Drug Administration, should describe the screening methods for known infectious agents before transplantation. Animals used should be procured from screened, closed herds or colonies that are well-characterized and as free as possible of infectious agents. They should have documented lineages and be bred and reared in captivity. Informed consent for patients should include disclosure of potential risks to the recipient, the family, or close contacts (especially sexual), and the need to archive pre-and post-transplant serum specimens for long-term follow-up.
Infection Control Practices. Standard precautions should be used for the care of all patients, including appropriate hand washing, use of barrier precautions, and care in the use and disposal of needles and other sharp instruments. Strict adherence to these recommended procedures will reduce the risk of transmission of xenogeneic infections and other bloodborne and nosocomial pathogens.
• Additional infection control or isolation precautions (e.g., airborne, droplet, contact) should be employed as indicated in the judgment of the hospital epidemiologist and the xenotransplant team infectious disease specialist. For example, appropriate isolation precautions for each hospitalized transplant recipient will depend upon the xenotransplant, the extent of immunosuppression, and the clinical condition of the recipient.
• The appropriateness of infection control measures should be considered at the time of transplant and re-evaluated during each readmission. Isolation precautions should be continued until a suspected xenogeneic infection has been proven and resolved or has been effectively ruled out in the recipient.
Acute Infectious Episodes. Most acute viral infectious episodes among the general population are never etiologically identified. Xenograft recipients remain at risk for these infections and other infections common among immunosuppressed allograft recipients. When the source of a significant illness in a recipient remains unidentified despite standard diagnostic procedures, more testing of body fluid and tissue samples may be appropriate. The infectious disease specialist, in consultation with the hospital epidemiologist, the veterinarian, the clinical microbiologist, and other members of the xenotransplant team should assess each clinical episode and make a judgment regarding the need and type of diagnostic testing and appropriate infection control precautions.
• Immunosuppressed transplant patients may be unable to mount a sufficient immunological response for serological assays to detect infections reliably. In this setting, appropriate validated culture systems, genomic detection methodologies and other techniques may detect diseases for which serologic testing is inadequate. Consequently, clinical centers where xenotransplantation is performed should have the capability to culture and to identify viral agents using in vitro and in vivo methodologies.
• Archiving of acute and convalescent sera obtained in association with acute unexplained illnesses should be performed when appropriate as judged by the infectious disease physician and/or the hospital epidemiologist. This would permit retrospective study and perhaps an etiologic diagnosis of the clinical episode.
Health care worker education and surveillance. A comprehensive occupational health services program should be designed to educate workers regarding the risks associated with xenotransplantation and to monitor for possible infections in workers. Health care workers, including laboratory personnel, who handle the animal tissues/organs prior to transplantation will have a definable risk of infection not exceeding that of veterinary workers exposed to the source animal species provided equivalent biosafety standards are employed. However, the risk to health care workers who provide direct/indirect post-transplantation care for xenograft recipients is undefined. Decisions regarding work restrictions or assignments for immunocompromised workers should be determined by each institution.
• All centers where xenotransplantation procedures are performed should develop appropriate educational materials for their staff tailored to each procedure. These materials should describe the xenotransplant procedure, and the known and potential risks of xenogeneic infections posed by the procedure. Those research or health care activities that are considered to be associated with the greatest risk of infection should be emphasized in order to minimize exposure and transmission of both zoonotic and nosocomial agents between the recipient and the health care workers. Use of standard precautions should be reviewed. Education programs should detail circumstances for use of personal protective equipment (e.g., gloves, gowns, masks, etc.) and the importance of hand washing before and after all patient contacts, even if gloves are worn. The potential for transmission of these agents to the general public should be discussed.
Collect, archive HCW sera
• Protocols should be developed for the collection and archiving of baseline sera (i.e., prior to exposure to xenografts or recipients) from health care workers either on the xenotransplant team or caring for xenograft recipients and any laboratory personnel who may handle the animal cells, tissues, and organs or future biologic specimens from transplant recipients. Archived sera serve as a baseline specimen for comparing sera collected following nosocomial exposures. In addition, these protocols should describe methods of recording, storing, and retrieving information related to health care workers and specific nosocomial exposures. The activities of the occupational health service should be coordinated with the infection control program to ensure appropriate surveillance of infections in personnel.
• Written protocols should be in place for the evaluation of health care workers who experience an exposure where there is a risk of transmission of an infectious agent, e.g., an accidental needlestick. Health care workers, including laboratory personnel, should be instructed to report exposures immediately to the occupational health service. The post-exposure protocol should describe the information to be recorded including the date and nature of exposure, the xenotransplantation procedure, recipient information, actions taken as a result of such exposures (e.g., counseling, post-exposure management and follow-up) and the outcome of the event. This information should be archived in a Xenotransplantation Nosocomial Health Exposure Log that documents the dates, involved persons, and nature of all nosocomial exposures associated with a xenotransplantation protocol and which potentially pose risk of transmission of xenogeneic infections. Health care and laboratory workers should be counseled to report and seek medical evaluation for unexplained clinical illnesses occurring after the exposure.
[Editor’s note: ICPs have until Dec. 22, 1996, to submit written comments on the draft guidelines to the Dockets Management Branch (HFA-305), Rockville, MD 20857. Requests and comments should be identified with docket number 96M-0311. The document may be obtained by mail or fax by calling the CBER Fax Information System at (888) CBER-FAX or (301) 827-3844.
People with access to the Internet may obtain the guidance document using FTP, the World Wide Web, or bounce-back e-mail. For FTP access, connect to CBER at ’ftp://ftp.fda.gov/cber/cberftp.html”. For bounce back e-mail send a message to ’[email protected]”.
For further information on the guidelines, contact Timothy Beth in the FDA Center for Biologics Evaluation and Research (HFM-630), Food and Drug Administration, 1401 Rockville Pike, Suite 200 North, Rockville, MD 20852-1448. Telephone: (301) 594-3074.]
Reference
1. Department of Health and Human Services. Draft Public Health Service guideline on infectious disease issues in xenotransplantation. Fed Reg Sept. 23, 1996; 49,919-49,932.
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