Handling HIV Safely In The Laboratory

Safe laboratory handling of the human immunodeficiency virus (HIV) presents paradoxical extremes to lab chiefs: The odds that a lab worker will become infected with HIV on the job are extremely low, according to studies sponsored by the Centers for Disease Control and Prevention (CDC) in Atlanta; but experience indicates that the consequences of infection are almost always fatal. Even noting the minority scientific view that HIV is not the cause of the acquired immunodeficiency syndrome (AIDS), a better-safe-than-sorry attitude demands that researchers take thorough precautions. According to the concept of "universal precautions," all human blood and certain human body fluids are treated as if known to be infectious for HIV or other bloodborne pathogens. The following practices, compiled from materials published by the Johns Hopkins University School of Medicine and the Canadian Centre for Occupational Health and Safety, can help lab workers put universal precautions into practice: Wear a lab coat or gown. Wear gloves when processing human specimens, when handling contaminated articles, and during cleaning and decontamination procedures. Change gloves and wash hands when processing is finished. Wash hands when procedures are complete, after removing protective clothing, before leaving the lab, and whenever there is a tear in a glove. Use a mask, safety glasses, goggles, or a face shield to protect eyes, nose, and mouth during procedures in which splashing or aerosolization is expected. Remove protective equipment and lab coat before leaving the lab. Handle sharp items with safety awareness. Maintain eye contact with the item. Use needles only when there is no alternative. Do not recap, bend, break, or remove needles by hand from disposable syringes. Discard sharp objects in puncture-resistant, labeled containers. Place these containers as close as possible to where "sharps" are used. Decontaminate lab materials and surfaces after a spill of blood or body fluid, before reprocessing contaminated material in lab tests, and when work activities are complete. Disinfect with a 1 percent solution of sodium hypochlorite or a 1:100-1:10 dilution of household bleach in water. Choose a suitable specimen container, avoid contaminating the outside of the container or the requisition, and be sure the lid is on tight. Decontaminate the outside of the container before transporting. When collecting specimens, do not force liquid into a vacuum tube collector. Never pipette by mouth. Use biological safety cabinets for procedures that are likely to create aerosols, such as blending. Use capped tubes when vortexing or centrifuging specimens. Shield machines which splash or splatter. Wrap a cotton or gauze pad moistened with disinfectant around rubber stoppers or lyophilized (freeze-dried) containers while opening them. --C.P. The challenge in the laboratory, then, is to control an occupational risk that is serious--but unlikely to occur. As Chris Carlson, acting biosafety officer at the University of California, Berkeley, says, "You have to find a balance between following good lab techniques and not getting hysterical about what you are doing." This balance is not something an individual lab has to work out on its own. The federal government has stepped in with a regulation called the Occupational Safety and Health Administration (OSHA) Bloodborne Pathogen Standard. This is a federal law (Code of Federal Regulations 1910.1030) that went into effect in March 1992. The "OSHA standard," as it is often called, spells out ways in which an employer must protect employees from occupational exposure to bloodborne pathogens such as HIV and hepatitis B. The OSHA bloodborne pathogen standard covers a broad spectrum of lab practices--including personal protective gear, containment of "sharps" (that is, needles and other lab equipment that may produce a cut), handling of contaminated laundry, and much more. The highly detailed, comprehensive OSHA document is not something that can be leafed through in an evening, and, in many large organizations, a biosafety officer oversees its implementation. Probably the most time-consuming part of implementing the OSHA standard is the preparation of a required document called an exposure control plan. According to the law, each facility where workers may be at risk of occupational exposure to blood or blood products must prepare a written exposure control plan. This generally lengthy document must list those employees who are at risk of infection, describe procedures for protecting them from infection, and outline a plan for evaluating exposure incidents. Although it takes time to prepare, a thoughtful exposure control plan can form a strong foundation for safe handling of HIV and other bloodborne pathogens in the lab. There is no shortcut: Exposure control plans are most useful when they are specific to an individual lab and its research. "An exposure control plan is not supposed to be generic," says Kinley Karlsen, an environmental health and safety/regulatory compliance consultant based in Belmont, Calif. "There are books and software packages that let you fill in the blanks for a `do- it-yourself' kind of plan, but you lose sight of the unique hazards of your lab. Then you have no way of correcting them or making sure people are trained properly." Karlsen, who has been hired by biotech companies to prepare their exposure control plans, says: "I look at the specific kinds of research they do, the specific tools and instruments they handle, and the kinds of samples they get in, then write an exposure control plan that identifies hazards that are unique to their facility." In determining which lab employees are at risk of occupational HIV infection, one must consider everyone who has anything to do with the lab, whether administrators, bench scientists, or custodial staff. Although the HIV-related health risk to lab workers, in general, is quite low, the degree of risk varies from one job classification to another, and from lab to lab. In some labs that study HIV, for example, the health risk may be nearly nonexistent because researchers handle only a portion of the actual virus. "From a practical point of view, the hazard of working with HIV is tremendously reduced by working with only part of the genome," explains Edward L. Gershey, director of laboratory safety at Rockefeller University in New York. "The level of infectivity is a thousandfold-and-more lower in this situation than when working with the whole virus." Scott Purvis, a graduate student working in a lab at University Hospitals of Cleveland, currently is investigating the effects of one particular HIV protein on human cells. "We've taken some of the genome that codes for protein," he says. "That's harmless. It can be done on the benchtop." Safety Equipment Lab Safety Supply P.O. Box 1368 Janesville, Wis. 53547-1368 (800) 356-0722 The Baker Co. Inc. P.O. Drawer E Sanford Airport Sanford, Maine 04073 (207) 324-8773 Training Materials Canadian Centre for Occupational Health and Safety 250 Main St., East Hamilton, Ontario Canada L8N 1H6 (416) 572-2981 Fax: (416) 572-2206 National Safety Council 444 N. Michigan Ave. Chicago, Ill. 60611 (312) 527-4800 National Institutes of Health DS/HIV Video Bldg. 31, Rm. 1C02 Bethesda, Md. 20892 The safety precautions for this project differ significantly from work Purvis has done in the past involving HIV-contaminated blood. In labs where researchers handle contaminated blood, the degree of risk from HIV is much greater than in labs that work with only portions of the virus. And in labs where the HIV virus is actually grown, the degree of risk is greater still. "Fortunately, research is usually divided into projects, and people have clearly delineated tasks," says Karlsen. "It is generally easy to distinguish who is at risk." One caveat, suggested by Carlson of UC-Berkeley, concerns a situation common to many labs, especially those in a university setting. "Frequently, more than one experiment is going on in a lab," Carlson says. "If anyone is working with HIV, everyone needs to know that." Preventing Exposure While many researchers and biosafety officers cite "common sense" as the key to safe handling of HIV in a lab, formal employee training should not be overlooked. Says consultant Karlsen: "You'd be surprised at how many people have never received any training. In school, the focus is on science. Students are never required to take a course in research safety." The passage of the OSHA bloodborne pathogen standard has spawned a mini-flood of lab employee training materials. Booklets, videos, slide sets, and instructor's materials are available from organizations such as the National Safety Council, the National Institutes of Health, and the Canadian Centre for Occupational Health and Safety. For those working with blood and body fluids, the CDC concept of "universal precautions" forms the foundation for safety training. This concept suggests that lab workers handle every sample as if it were potentially hazardous or contaminated (see accompanying story). Yet even when lab workers practice universal precautions perfectly, accidental HIV exposure can occur. "Gloves will protect you from exposure, but a needle can go right through a glove," says Karlsen. "An accident is an accident." Where many formal exposure control plans fall short, according to UC-Berkeley's Carlson, is in planning for what to do in the moments immediately following accidental HIV exposure. "Most exposure control plans tell you who to contact in case of an emergency and what kind of medical care should be given," Carlson says. "But at our university, the health facility can be a 10-minute walk away. What's missing from most plans is what to do immediately." According to scientists and biosafety professionals, lab workers do understand the need for caution in their work. Says Carlson, "More written procedures contain safety considerations, and caution is becoming more and more part of the routine." Caren D. Potter is a freelance science writer based in McKinleyville, Calif.

Handling HIV Safely In The Laboratory

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