Researchers have developed a mathematical model to examine the potential of contact tracing to reduce the spread of the coronavirus.
There is plenty of evidence that one of the keys to stopping the spread of COVID-19 is contact tracing: identifying people who may have come into contact with an infected person and alerting them to that fact.
The United States is the global leader in deaths from the virus, yet there is no national effort to adopt a cohesive contact-tracing plan. As a result, public health departments in most states have established their own plans, hiring contact tracers to fan out in their communities and build maps to show who has come into contact with people who have tested positive for the virus. The data lets public health officials know where transmissions are happening and when it’s safe to ease up on lockdowns and quarantines.
Most importantly, contact tracing can lead to earlier identification of people who may be infected, and they can be encouraged to quarantine and isolate.
Stanford Health Policy’s Joshua Salomon, PhD, professor of medicine and senior fellow at the Freeman Spogli Institute for International Studies, and his colleagues have developed a mathematical model to examine the potential of contact tracing to reduce the spread of the coronavirus. They modeled contact-tracing programs in the context of relaxed physical distancing, varying the percentage of hypothetical symptomatic infections detected in a community from 10% to 90% compared with scenarios without contact tracing.
They found that detection of cases in the community and successful outreach to contacts both need to exceed 50% for contact tracing to reduce transmissions significantly. They also found that the most effective programs — those with high levels of testing, tracing, isolation and quarantine efficacy — could reduce overall transmission by almost half. Such a benefit would allow for considerable loosening of physical-distancing measures and public health restrictions while still helping control the spread of COVID-19.