Canadian laboratory incidents with human pathogens and toxins: An overview of reports, 2016-2022.

Background: When the Public Health Agency of Canada's Human Pathogens and Toxins Act and Human Pathogens and Toxins Regulations came into force, the reporting of laboratory incidents to the Laboratory Incident Notification Canada (LINC) surveillance system became mandatory. This report summarizes the laboratory exposure and non-exposure data reported from 2016 to 2022, with a particular focus on factors that are not typically presented in LINC's annual report. Methods: Reported laboratory incidents from 2016 to 2022 were analyzed. Exposures were analyzed by severity, occurrence and root cause, and affected individuals were analyzed by disease outcome, role and applied interventions. Non-exposures were analyzed by incident type. Exposure and non-exposure incident rates were calculated. Results: Events reported to LINC totalled 928. Of those, 355 were confirmed non-exposures, 361 were confirmed exposures, and 111 were other events. Both exposure and non-exposure incident rates per 100 active licences peaked in 2018 (9.44 and 7.11, respectively). Most exposures were rated as minor or negligible severity. The most cited exposure occurrence types were sharps-related and procedure-related (23% each), and standard operating procedure-related root causes were most cited (24%). While 781 individuals were affected in the exposure incidents, most did not develop a laboratory-acquired infection (n=753; 96%) and received at least one form of treatment post-exposure (n=717; 92%). Inadvertent possession/production cases were the most common non-exposure incidents reported. Conclusion: Exposure and non-exposure incident rates have decreased since 2018. Among exposure incidents, sharps-related and procedure-related occurrences were the most common, and the root cause was usually a standard operating procedure. Non-exposure incidents were mostly inadvertent possession/production cases. Exposure and illness outcome severity was mostly minor.

Surveillance of laboratory exposures to human pathogens and toxins, Canada, 2022.

Background: The Laboratory Incident Notification Canada (LINC) surveillance system was launched in 2015 to monitor the mandated national reporting of laboratory incidents. This report describes the laboratory exposures reported in 2022. Methods: Exposure incidents were analyzed by activity, occurrence, sector, root cause and pathogens/toxins implicated, while affected individuals were analyzed by education, exposure route, role and years of laboratory experience. An analysis of the median number of exposures per month was conducted, and time between the exposure incident date and the date the incident was reported to LINC was examined. Results: Forty confirmed laboratory exposure incident reports were received, with two suspected laboratory-acquired infections. The exposure incident rate per 100 active licences was 3.8, and the number of exposure incidents was highest in September. The majority of exposure incidents involved risk group 2 pathogens (n=27; 63%) and non-security sensitive biological agents (n=36; 84%). Microbiology was the most cited activity occurring during the exposure event (n=20; 50%), and sharps and procedure-related issues were the most common occurrences (n=15; 24.2% each). Most incidents were reported by the academic sector (n=16; 40%). Human interaction was the most common root cause (n=20; 23.8%) and most affected individuals were technicians/technologists (n=68; 73.1%). The median time delay between the incident date and reporting date was 5.5 days. Conclusion: The exposure incident rate was lower in 2022 than in 2021. Incidents related to sharps and standard operating procedures remained the most common occurrence types. The most cited root cause of exposure incidents involved human interaction.

Surveillance of laboratory exposures to human pathogens and toxins, Canada, 2021.

Background: The Laboratory Incident Notification Canada surveillance system monitors laboratory incidents that are mandated to be reported under the Human Pathogens and Toxins Act and the Human Pathogens and Toxins Regulations. This article describes laboratory exposure incidents that occurred in Canada in 2021 and individuals affected in these incidents. Methods: We extracted all laboratory incidents occurring in licensed Canadian laboratories in 2021 from the Laboratory Incident Notification Canada system and analyzed them using the software R. We calculated the rate of exposure incidents and performed descriptive statistics by sector, root cause, activity, occurrence type and type of pathogen/toxin. Analysis of the education level, route of exposure, sector, role and laboratory experience of the affected persons was also conducted. We conducted seasonality analysis to compare the median monthly occurrence of exposure incidents between 2016 and 2020 to monthly incidents in 2021. Results: Forty-three exposure incidents involving 72 individuals were reported to Laboratory Incident Notification Canada in 2021. There were two confirmed laboratory-acquired infections and one suspected infection. The annual incident exposure rate was 4.2 incidents per 100 active licenses. Most exposure incidents involved non-Security Sensitive Biological Agents (n=38; 86.4%) and human risk group 2 (RG2) pathogens (n=27; 61.4%), with bacteria (n=20; 45.5%) and viruses (n=16; 36.4%) as the most implicated agent types. Microbiology was the most common activity associated with these incidents (n=18; 41.9%) and most incidents were reported by the academic sector (n=20; 46.5%). Sharps-related (n=12; 22.2%) incidents were the most common, while human interaction (e.g. workload constraints/pressures/demands, human error) (n=29, 28.2%) was the most common root cause. Most affected individuals were exposed through inhalation (n=38; 52.8%) and worked as technicians or technologists (n=51; 70.8%). Seasonality analyses revealed that the number of exposure incidents reported in 2021 were highest in September and May. Conclusion: The rate of laboratory incidents was slightly lower in 2021 than in 2020. The most common occurrence type was sharps-related while issues with human interaction was the most cited root cause.

Serum antibody response in COVID-19-recovered patients who retested positive.

BACKGROUND: Research studies comparing antibody response from coronavirus disease 2019 (COVID-19) cases that retested positive (RP) using reverse transcription polymerase chain reaction (RT-PCR) and those who did not retest positive (NRP) were used to investigate a possible relationship between antibody response and retesting status. METHODS: Seven data bases were searched. Research criteria included cohort and case-control studies, carried out worldwide and published before September 9, 2020, that compared the serum antibody levels of hospitalized COVID-19 cases that RP after discharge to those that did NRP. RESULTS: There is some evidence that immunoglobulin G (IgG) and immunoglobulin M (IgM) antibody levels in RP cases were lower compared with NRP cases. The hypothesis of incomplete clearance aligns with these findings. The possibility of false negative reverse transcription polymerase chain reaction (RT-PCR test results during viral clearance is also plausible, as concentration of the viral ribonucleic acid (RNA) in nasopharyngeal and fecal swabs fluctuate below the limits of RT-PCR detection during virus clearance. The probability of reinfection was less likely to be the cause of retesting positive because of the low risk of exposure where cases observed a 14 day-quarantine after discharge. CONCLUSION: More studies are needed to better explain the immune response of recovered COVID-19 cases retesting positive after discharge.

Assessing the progression of the COVID-19 pandemic in Canada using testing data and time-dependent reproduction numbers.

OBJECTIVES: To compare a mathematical tool and time-dependent reproduction number (Rt) estimates to assess the COVID-19 pandemic progression in a Canadian context. METHODS: Total number of reported cases were plotted against total number of tests for COVID-19 performed over time, with and without smoothing, for Canada and some Canadian provinces individually. Changes in curvature profile were identified as either convex or concave as indicators of pandemic acceleration or deceleration, respectively. Rt estimates were calculated on an exponential growth rate. RESULTS: For Canada as a whole, the testing graphs had a slightly concave profile and a coincident decrease in Rt estimates. Saskatchewan more recently had a convex profile with a gradual shift to a concave profile and also demonstrated a gradual decline in Rt estimates. Curves and Rt estimates for Alberta, British Columbia, Manitoba, Nova Scotia, Ontario and Quebec displayed a gradual shift towards concavity over time and an overall decrease in Rt estimates, which is suggestive of a positive impact of public health interventions implemented federally and provincially. CONCLUSION: The present analyses compared a mathematical tool to Rt estimates to ascertain the status of the pandemic in Canada. Caution should be taken when interpreting results due to factors such as varying testing protocols, available testing data unique to each province and limitations inherent to each method, which may generate different results using the two approaches. Analysis of testing data may complement metrics obtained from surveillance data to allow for a weight-of-evidence approach to assess the status of the COVID-19 pandemic.

RéSUMé: OBJECTIFS: Comparer un outil mathématique aux estimations du taux de reproduction en fonction du temps (Rt) pour évaluer la progression de la pandémie de la COVID-19 dans le contexte canadien. MéTHODES: Le nombre total de cas signalés a été comparé au nombre total de tests à la COVID-19 effectués au fil du temps, avec et sans lissage, pour le Canada et certaines provinces canadiennes individuellement. Les modifications du profil de courbure identifiées comme étant convexes ou concaves seraient des indicateurs respectivement d'une accélération ou d'une décélération de la pandémie. Le calcul des estimations du Rt a été réalisé en fonction du taux de croissance exponentiel. RéSULTATS: Pour l'ensemble du Canada, la légère concavité des graphiques relatifs aux tests coïncidait avec la diminution des estimations du Rt. Plus récemment, la Saskatchewan avait un profil convexe avec un passage progressif à un profil concave et a également démontré une baisse progressive des estimations du Rt. Les courbes et les estimations du Rt pour l'Alberta, la Colombie-Britannique, le Manitoba, la Nouvelle-Écosse, l'Ontario et le Québec ont montré un glissement progressif vers la concavité au fil du temps et une diminution globale des estimations du Rt, ce qui suggère un impact positif des interventions de santé publique mises en œuvre au niveau fédéral et provincial. CONCLUSION: Les présentes analyses ont comparé un outil mathématique aux estimations de Rt pour déterminer l'état de la pandémie au Canada. Les résultats doivent être interprétés avec prudence en raison de certains facteurs tels que les différences entre provinces en ce qui concerne les protocoles de réalisation des tests et la disponibilité des données relatives aux tests. De plus, une limite inhérente à la méthodologie de cette étude est la possibilité d'obtenir des résultats différents en fonction de l'approche utilisée. L'analyse des données des tests pourrait être complémentaire à celle des données de surveillance pour permettre une approche fondée sur le poids de la preuve dans le cadre de l'évaluation de l'état de la pandémie de la COVID-19.