Wkdxr 12. 1979 nr . Keith Hadley Carps BiosaEety Ccarmittee Dear Keith: As you know, I am initiating a mall project to study the behavior of hepatitis B virus, and our department has recently renovated a small room in the Science building for this purpe. sims with other investigators and officials at the Center for Disease Control (CDC), and a visit to Dr. W. Winson's labratory at Stanford, it appears that the cardinal safety features in such work involve careful techniques rather than exper.sive equipnent. We therefore planned to wrk in an isolated room, with sterile procedues (inculcling use of gloves, avoidance of muth pipetting, etc.), ma to decontaminate all materials prior to their ramval fxm the isolation facility. Concentratj.on of virus by centrifugation would k pxformed in capped centrifuge tubs in a machine in the isolatian roan. Based upon my readings of the literature, discus- The current guidelines issued by th ESF Biosafety Cornnittee indicate that such precautians are inadequate for work with this agent. that hepatitis B virus, along with a few other viruses, including herpesviruses, ccrsidered to bw Class I1 agents by the UX, must instead he worked with as tfmugh they were Class 111 agents. The shift in classification is of sane prae tical. importance, since it requires that rxqative pressure (not generally avail- able in laboratories in the Science building) md expensive cmd awkwzrd hiolclg- icai safety cabinets be employed in such work. A brief survey of laboratories cm this or other campuses reveals that such strictures are not adhered to for knrk with hepatitis B agent (or herpesviruses) ; furthemre, officials at the CDC do not remiend such restrictins. These widespread practices and CX recmendatisns do not reflect carelessness, but rather a recognition thst viruses such as hepatitis H are widespread in clinical materiais (making such strictures impractical) and not know to be transmitted by an airimrno route (making such strictures unnecessary). In m] conversations with safety officers at the a, I learned that the new CDC guidelines will emphasize that a indivi- dual investigators should use com~on sense in wrking with such agents. exanpie, ccmcentratim of virus by centrifugation stiould be performed using capped tScs CK using centrifuges in biolcqically mntclincc? facilities. er, hepatitis 13 will cmntinue to be classified as a Class I1 ager!t. The Camnittee has ruled Fbr Hawev- ocmhsr 12, 1979 1 therefore request that the Biosafety Cmittee remnsicler its exceptions to the CDC classifi.catisn m3 adjust its reromnendaticms in the light of current practice and kmd&gc. Since we wish to canform with the plieies of the can- mittee and yet, naturally, & not wish to delay our work, I woulA he please6 to receive aclvicu! from yau at the earliest psible time. Yours, Haroid E. Varmus, M.D. Professor of Microbiology and Imnwl~