Why contact tracing may be a mess in America

High caseloads, low testing, and American attitudes toward government authority could pose serious challenges for successful efforts to track and contain coronavirus cases.

Alaska, California, Massachusetts, New York, and others are collectively hiring and training tens of thousands of people to interview infected patients, identify people they may have exposed, and convince everyone at risk to stay away from others for several weeks.

Contact tracing is a proven tool in containing outbreaks of highly infectious diseases. But this particular virus could pose significant challenges to tracing programs in the US, based on new studies and emerging evidence from initial efforts. Stubbornly high new infection levels in some areas, the continued shortage of tests, and American attitudes toward privacy could all hamstring the effectiveness of such programs.

The chief challenge with this coronavirus is its potential to spread exponentially: absent containment measures, every infected person on average will infect two or three others, according to most estimates (although some studies find it could be higher).

A team in any given region would have to detect at least half of new symptomatic cases, and reach at least half the people they were in close contact with and encourage them to stay away from others, in order to reduce the transmission rate by 10% or more, according to a new model.

If they successfully detected 90% of symptomatic cases and reached 90% of their contacts—and tested all of them regardless of whether they had symptoms—it could reduce transmissions by more than 45%, the researchers found.

In other words, if social distancing in a given region had reduced infections per person from 2.6 to 1, this level of contact tracing could push it down to .55. Or the region could ease distancing measures by about half and keep infection levels constant.

Will technology help? Smartphone apps are playing a role in many countries but not the U.S.A.

The American psyche

Successful contact tracing efforts also require people to accept calls and heed advice from complete strangers.

Unfortunately, years of robocalls and telemarketing have conditioned many Americans to ignore calls from numbers they don’t recognize. Jana De Brauwere, a program manager with the San Francisco Public Library who is working with the city’s contact tracing task force, says that at least half the people she calls simply don’t answer. Others hang up once she starts asking for personal information, like addresses and dates of birth.

Americans pride themselves on privacy and freedom, another hindrance to gathering public health information, as well as conspiracy theorists. In a Twitter thread earlier this week, Keith Humphreys, a professor of psychiatry and behavioral sciences at Stanford, argued that public health officials are underestimating how much US attitudes toward government authority could undermine national testing and tracing programs.

Americans have already defied the orders of health officials in several prominent incidents, including assaults on store workers who asked people to wear masks, armed demonstrators protesting stay-at-home restrictions, and businesses that have reopened before their local government gave the go-ahead.

Public health orders work only when there’s a public that will abide by them.

The US is amassing an army of contact tracers to contain the covid-19 outbreak. But they'll face major challenges. | MIT Technology Review