Infection Risks Faced by Public Health Laboratory Services Teams When Handling Specimens Associated With Coronavirus Disease 2019 (COVID-19)

Infection risks of handling specimens associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by public health laboratory services teams were assessed to scrutinize the potential hazards arising from the work procedures. Through risk assessments of all work sequences, laboratory equipment, and workplace environments, no aerosol-generating procedures could be identified except the procedures (mixing and transfer steps) inside biological safety cabinets. Appropriate personal protective equipment (PPE) such as surgical masks, protective gowns, face shields/safety goggles, and disposable gloves, together with pertinent safety training, was provided for laboratory work. Proper disinfection and good hand hygiene practices could minimize the probability of SARS-CoV-2 infection at work. All residual risk levels of the potential hazards identified were within the acceptable level. Contamination by gloved hands was considered as a major exposure route for SARS-CoV-2 when compared with eye protection equipment. Competence in proper donning and doffing of PPE accompanied by hand washing techniques was of utmost importance for infection control.

Laboratory containment of SARS virus

Following the severe acute respiratory syndrome (SARS) outbreak in 2003, a large number of clinical and environmental samples containing/potentially containing SARS coronavirus (SARSCoV) as well as SARS-CoV stocks were retained in clinical and research laboratories. The importance of laboratory biosafety was demonstrated by the occurrence of laboratory incidents in Singapore, Taiwan and Beijing. It is imperative that safe practice and techniques, safety equipment and appropriate facility design should be in place to reduce or eliminate exposure of laboratory workers, other persons and the outside environment to SARS-CoV containing materials. Discussion on laboratory containment of SARS-CoV was initiated in Hong Kong in August 2003. It was agreed that an inventory of all specimens with the potential presence of SARS-CoV collected for any diagnostic or research purposes from November 2002 to July 2003 should be established in each laboratory. They should be stored in a secure place at the appropriate biosafety level with access control. Un-needed samples collected during the period should be destroyed. These laboratories should be audited to ensure inventories are updated. The audit should include safety and security measures to detect irregularities. Any laboratory accidents involving materials suspected of containing SARS-CoV should be reported to the authorities and all personnel exposed closely followed medically. A contingency plan should be in place in the laboratory and a drill conducted regularly to test its efficacy. By January 2004, all clinical laboratories performing SARS-CoV testing in Hong Kong set up inventories to document location and types of SARS-CoV containing materials retained in their laboratory. Audits of these laboratories in 2004 showed that laboratory safety and containment requirements as recommended were generally met.