SARS-Coronaviruses and Highly Pathogenic Influenza Viruses
An Appendix to SARS and HPI Laboratory Biosafety Protocols
Introduction
The international scientific community moved with remarkable speed to identify the causative agent of Severe Acute Respiratory Syndrome (SARS) and to develop assays to detect the SARS coronavirus (SARS-CoV). These steps, along with isolation and quarantine, helped limit transmission of the newly identified public health threat and contain the outbreaks to parts of Canada and the Far East. However, recent cases of laboratory-acquired SARS infections in Bejing, Singapore and Taipei, have raised concerns about laboratories becoming the sources of new outbreaks. The emergence of highly pathogenic avian influenza viruses that have been transmitted to humans has also increased the biocontainment burden on laboratories performing research with these agents.
Work with these agents presents unique challenges because biocontainment and exposure management is critical, not only for the health of laboratory personnel, but also to prevent escape and potential infection of the local human and animal populations. The severe consequences to public health and agriculture of accidental release of these agents make early detection and containment of laboratory infections critical. In parallel, the rapid discrimination of work-related infections from the inevitable commonplace respiratory infections that occur in laboratory staff is essential. Thus, the medical monitoring and event-response protocols must be designed so as to support valuable research and also protect public health.
While we cannot guarantee that a laboratory accident will never occur, we do have a responsibility to ensure that the work is performed at the highest appropriate biosafety level, that laboratory accidents are fully documented and that potentially exposed staff are monitored to minimize the risk that a work-related infection will go undetected and spread to family and community contacts. While laboratory safety protocols exist for working with SARS-CoV and highly pathogenic influenza (HPI) viruses, there is a need to expand the guidance on how to respond both to exposure events and to respiratory illness in laboratory workers. The situation is exacerbated by the limited information on routes of transmission and the viral dose required for infection. Because of the adverse public health consequences of a laboratory infection spreading to the community, the natural tendency will be to plan very conservatively and to err on the side of caution. While this is the appropriate approach given our current lack of knowledge we, nonetheless, do not want to place unnecessarily restrictive limitations on the scientists performing this important research. Given the pre-existence of comprehensive laboratory safety protocols, we therefore consider that the critical component of this plan is the formation of a Risk Assessment Group that is composed of individuals with the appropriate expertise to allow evaluation of the potential for infection. A detailed description of the Risk Assessment Group can be found in Section 7 of this protocol. It is the role of this group to review all factors leading up to the event or illness, and to determine the appropriate response. Because it is not possible to address every possible scenario in a written protocol, good practice will depend heavily upon the exercise of good judgment by the Risk Assessment Group. We believe that if this protocol is followed in a timely fashion, the risk of spread of infection will be greatly minimized.
This protocol is divided into sections that reflect the sequence of actions and outcomes that will occur following either a laboratory event creating a potential exposure or the development of respiratory illness in a laboratory worker.