issues and experts

Limits of COVID-19 contract tracing - SFU researchers available

December 22, 2020

SFU researchers Caroline Colijn and Paul Tupper are available to discuss new preprint research about the limits of contact tracing in containing the spread of COVID-19 and the need for broadened and proactive testing.

The researchers say contact tracing alone is insufficient to prevent exponential growth in the number of cases, without other measures in place. It is most effective when contacts are informed before they have entered their own infectious period, because this can prevent further infections. 

Contact tracing is made far less effective by delays in testing, calling and isolating – these mean that contacts may already have infected others by the time they know they have been exposed. 

The researchers say rises in cases or contacts risk overwhelming contact tracing systems, increasing delays and further undermining COVID-19 control. 

They also make that case that much anticipated jurisdictional reopenings, to avoid the high costs of shutdown, cannot happen if primary COVID-19 controls are based on symptomatic testing and contact tracing.

The solution they propose is to broaden testing considerably, and to include individuals without symptoms (who may be infected, but either asymptomatic or in that period of time between being infected and symptom onset).

Proactive testing can help manage case counts and avoid the use of strong widespread distancing measures. They suggest using fast cheap tests that can be deployed widely, pooled testing, or screening judiciously chosen groups of high-risk individuals. 

The preprint research is published in MedRxiv. 


CAROLINE COLIJN, Canada 150 Research Chair in Mathematics for Evolution, Infection and Public Health                            

PAUL TUPPER, professor, mathematics             


MELISSA SHAW, SFU  Communications & Marketing 
236.880.3297 |

Simon Fraser University 
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