Doubts About Contact Tracing

by Edward Peter Stringham – AIER

In the movies, it all seems easy. There is a pandemic. You discover the sick person and trace where he or she has been and with whom. You notify and test those people. Find the positive cases and trace further. 

In the 2011 movie Contagion, they find the original carrier and trace her steps back to a restaurant in China, and the chef who made her food, and the pig the chef slaughtered and then to the bat that fell into the trough. 

It’s science! 

In real life, it’s a different matter. Somehow during this pandemic, the idea of contact tracing has been held out as some sort of panacea. Your new smartphone software probably has the technology which is set to alert you if you come near someone previously seen as COVID positive or enter into some hot zone. Or if you get the virus, others will be notified of your presence – perhaps like a leper bell from the Middle Ages. 

I have my doubts that most people want that on their phones but most won’t know how to turn it off

Regarding these apps, Brookings writes:

The lure of automating the painstaking process of contact tracing is apparent. But to date, no one has demonstrated that it’s possible to do so reliably despite numerous concurrent attempts. Apps that notify participants of disclosure could, on the margins and in the right conditions, help direct testing resources to those at higher risk. Anything else strikes us as implausible at best, and dangerous at worst.

Sheridan Prasso of Bloomberg offers additional insight:

Of the 47 contact-tracing apps already in use in 28 countries as of mid-May, 23% of them had no privacy policy, 53% don’t disclose how long they plan to keep user data, and 60% had no publicly stated anonymity measures, Top10VPN’s Woodhams found. None has reached the 60% download level needed to be effective. An April white paper by the American Civil Liberties Union also said that most location-tracking methods used by apps are too inaccurate to be useful for automated tracking.

A poll by Axios and Ipsos Group found 66% of respondents said they would reject an app developed by tech companies, and even more wouldn’t download one from the U.S. government. “The whole concept of American democracy is about local control and civil liberties,” Cliff Young, president of Ipsos U.S. Public Affairs, said in a statement with the poll results.

In addition to contact tracing apps, right now governments are hiring thousands of people to work for government as detectives through widespread contact tracing. Many officials say the government must hire 300,000 (that would be one out of every thousand people in the country) to work as contact tracers. 

It works as follows. Someone tests positive for COVID-19. The contact tracer then investigates where the person lives, his family and friends, and compiles a list of everyone with whom the COVID-19 patient has had contact. The contact tracer then knows everyone who has potentially been exposed and can be in touch with them. 

But tracing the source and all possible people exposed to this airborne virus is easier said than done. Consider the typical New Yorker who may have in the last week been to the store twice, took delivery of packages from two UPS employees, ridden the elevator with 20 other people, and been on the subway ten times. If you touch a surface in Penn Station it may have been touched by any of the other 600,000 passengers who historically go through Penn Station, each day. Just count up all of the thousand surfaces you have touched in the past week and all the people you see. 

Then what does the investigator do? The investigator makes a list, investigates for phone numbers and addresses, and taps a case worker to start making calls. “You have been in contact with someone who is COVID positive, and we would like you to come in for a test.” 

The contact tracer then requires that everyone potentially exposed to the virus stay home for two weeks. 

Talk about a way to panic the public! Just the prospect of kicking off this incredibly invasive process might deter people from ever going to the hospital in the first place. 

But let’s say that you can somehow develop a map of the travels of a virus from here to there and there, and you can watch this visualization. What precisely can you do with this information? There is zero hope that you can somehow freeze all these people in place, and, even if you could, nothing about mapping and tracing causes the virus to go away. 

A Yale graduate student was recently working as a contact tracer and is alerting the public about some of the downsides of how contact tracing in Connecticut is working. 

She found the job frustrating and didn’t like poking into peoples’ lives. All she was able to do was warn people and offer vague guidance. Imagine getting routine calls from government officials who “work like a detective, asking about co-workers met, errands run, shops visited, events attended” and queries like, “What did you have for breakfast, for lunch, did you go shopping, did you go to the barber shop?” And then imagine getting calls each time you were at a place that had a COVID-19 carrier. I personally like to keep my interaction with the other 4.3 million daily subway riders in New York to a minimum. What will people even be able to do with such information? 

One must wonder too about the coercive aspects to this. 

Q&A from Washington State offers some not very comforting assurances

Q: What happens if I don’t comply?

A: If health officials think you’re at risk and are worried about you not complying, they’ll ask you to sign a form which says you will voluntarily self-isolate. If you still don’t comply, you could face a fine or jail time.

Q: Will I or my kids be placed in isolation centers?

A: No. The state has some isolation centers available for foster kids or people with no safe place to go. At no point, will anyone drag you or your kids out of your home.

Q: Why is the National Guard involved?

A: They are only acting as volunteers, not law enforcement. They will help like they are doing at the food banks in town.

Q: Will my privacy be violated?

A: No. Your information is confidential just like it is at a doctor’s office.

Imagine being assured of the same privacy as a visit to the doctor’s office, except the contact tracer tracks down and interviews everyone with whom you interacted.

Contact tracing might make sense for certain diseases. But it turns out that there is no evidence that this novel coronavirus can be contained by contact tracing. 

Let us consider some of the articles on this topic. 

Non-pharmaceutical public health measures for mitigating the risk and impact of epidemic and pandemic influenza. World Health Organization (2019) 

Active contact tracing is not recommended in general because there is no obvious rationale for it in most Member States.

Feasibility of controlling COVID-19 outbreaks by isolation of cases and contacts. Authors: Joel Hellewell, PhD, Sam Abbott, PhD, Amy Gimma, MSc, Nikos Bosse, BSc Christopher Jarvis, PhD, Timothy W Russell, PhD, James D Munday, MSc, Adam J Kucharski, PhD, Prof W John Edmunds, PhD, Centre for the Mathematical Modelling of Infectious Diseases COVID-19 Working Group, Sebastian Funk, PhD, Rosalind M Eggo, PhD 

“Isolation of confirmed and suspected cases, and identification of contacts are a crucial part of these control efforts; however, whether these efforts will achieve control of transmission of COVID-19 is unclear…Isolation of cases and contact tracing becomes less effective if infectiousness begins before the onset of symptoms.”

“Outbreak control was defined as no new infections between 12 and 16 weeks after the initial cases. Outbreaks that reached 5,000 cumulative cases were assumed to be too large to control within 12–16 weeks, and were categorised as uncontrolled outbreaks. Based on this definition, we reported the probability that an outbreak of a severe acute respiratory syndrome coronavirus 2-like pathogen would be controlled within 12 weeks for each scenario, assuming that the basic reproduction number remained constant and no other interventions were implemented.”

“These outbreaks required a large number of cases to be contact traced and isolated each week, which is of concern when assessing the feasibility of this strategy. Subclinical infection markedly decreased the probability of controlling outbreaks within 3 months.”

Factors that make an infectious disease outbreak controllable. Authors: Christophe Fraser, Steven Riley, Roy M. Anderson, and Neil M. Ferguson

“We show that the success of these control measures is determined as much by the proportion of transmission occurring prior to the onset of overt clinical symptoms (or via asymptomatic infection) as the inherent transmissibility of the etiological agent (measured by the reproductive number R 0).From published studies, we estimate these quantities for two moderately transmissible viruses, severe acute respiratory syndrome coronavirus and HIV, and for two highly transmissible viruses, smallpox and pandemic influenza. We conclude that severe acute respiratory syndrome and smallpox are easier to control using these simple public health measures. Direct estimation of the proportion of asymptomatic and presymptomatic infections is achievable by contact tracing and should be a priority during an outbreak of a novel infectious agent.”

Comparing nonpharmaceutical interventions for containing emerging epidemics. Authors: Corey M. Peak, Lauren M. Childs, Yonatan H. Grad, and Caroline O. Buckee

“The comparative effectiveness of symptom monitoring and quarantine depends critically on the natural history of the infectious disease, its inherent transmissibility, and the intervention feasibility in the particular healthcare setting.”

Disease contact tracing in random and clustered networks. Authors: Istvan Z Kiss,* Darren M Green, and Rowland R Kao

“The efficacy of contact tracing, be it between individuals (e.g. sexually transmitted diseases or severe acute respiratory syndrome) or between groups of individuals (e.g. foot-and-mouth disease; FMD), is difficult to evaluate without precise knowledge of the underlying contact structure; i.e. who is connected to whom? Motivated by the 2001 FMD epidemic in the UK, we determine, using stochastic simulations and deterministic ‘moment closure’ models of disease transmission on networks of premises (nodes), network and disease properties that are important for contact tracing efficiency. For random networks with a high average number of connections per node, little clustering of connections and short latency periods, contact tracing is typically ineffective. In this case, isolation of infected nodes is the dominant factor in determining disease epidemic size and duration. If the latency period is longer and the average number of connections per node small, or if the network is spatially clustered, then the contact tracing performs better and an overall reduction in the proportion of nodes that are removed during an epidemic is observed.”

Open Letter: Contact Tracking and NHSX signed by many dozens of health professionals and technologists in the UK

Contact tracking is unlikely to be effective in a country where not everyone has a mobile phone, and where many people live in shared accommodation — not everyone who carries the virus can or will be tracked, and cell recognition is not good enough to differentiate between people who, for instance, live in a single block of flats. Not only does this kind of surveillance risk contravening human rights, but it is not guaranteed to work — particularly at this stage of the Coronavirus outbreak.

In the UK, OFCOM figures show that 22% of UK adults do not have a smartphone, rising to 45% of adults over 55, and figures on device ownership for young children vary wildly. Relying on this data exclusively risks reinforcing existing inequalities, especially if it could be used to establish reasonable or reliable grounds for a person to be detained.

It is not yet clear how data will be collected, or used, within the legal framework. Nor what technical safeguards will be used. We are also concerned that data collected to fight Coronavirus could be stored indefinitely or for a disproportionate amount of time, or will be used for unrelated purposes.

These are testing times, but they do not call for untested new technologies. Ethical data-driven decision-making requires good governance, transparency and willingness to course correct.

In The Limits of Location Tracking in an Epidemic, Jay Stanley and Jennifer Stisa Granick of the ACLU write, 

At the same time, location data contains an enormously invasive and personal set of information about each of us, with the potential to reveal such things as people’s social, sexual, religious, and political associations. The potential for invasions of privacy, abuse, and stigmatization is enormous.

Data on individuals’ locations is not accurate enough for automated contact tracing.

We have spoken with engineers and executives at a number of the largest U.S. companies that hold location data on Americans’ movements and locations, and generally they have told us that their data is not suitable for determining who was in contact with whom for purposes of COVID-19 contact tracing.

The CDC warns against coming in “close contact” with a person who has tested positive for the virus, defining close contact as “being within approximately 6 feet (2 meters), of a person with COVID-19 for a prolonged period of time.” None of the data sources discussed above are accurate enough to identify close contact with sufficient reliability. None are reliably accurate to within 6 feet. Using the wrong technology to draw conclusions about who may have become infected might lead to expensive mistakes such as two week isolation from work, friends, and family for someone — perhaps even a health care worker or first responder — who was actually not exposed. Israel’s use of location data has already sparked complaints about accuracy.

The algorithms are not likely to be reliable.

Even if we were to imagine a set of location data that had pinpoint accuracy, there would still be problems translating that in any automated way into reliable guesses about whether two people were in danger of transmitting an infection. The Israeli system apparently acts on the basis of nothing more than an automated look at proximity. In Israel, one woman was identified as a “contact” simply because she waved at her infected boyfriend from outside his apartment building — and was issued a quarantine order based on that alone.

The data is fragmented and may be biased.

Complicating matters further, no single, centralized party holds the location data generated by Americans. Most location data with any level of precision is generated by an essentially corrupt ecosystem of shady, privacy-invading companies that engage in mass location tracking without individuals’ meaningful awareness or consent, typically by paying the developers of smartphone apps to hide tracking capabilities inside those apps. This location data is scattered among dozens of such companies most Americans have never heard of.

Proposed Use: Enforcement

Another possible use of location information is in the enforcement of quarantines, shelter-in-place orders, and travel restrictions. These uses contemplate turning people’s cell phones into ersatz ankle monitors.

Aggregate data could also be used to enforce compliance with stay-at-home orders. For example, companies could notify the authorities when cell phone data suggested that people were gathering in numbers prohibited by local public health measures, without sharing the identities of those who appear to have gathered, such as at a rogue bar that appeared in Los Angeles during a shelter-in-place regime. Such measures would have to be used with care lest multi-story apartment buildings or the like trigger alarms.

Public health experts caution, however, that a law enforcement approach to combatting disease is less effective than relying on voluntary measures and compliance. That is because an enforcement approach often sparks counterproductive resistance and evasion and tends to sour the relationship between citizens and their government at a time when trust is of paramount importance. Good public health measures leverage people’s own incentives to report disease and help stop its spread.

Edward Peter Stringham

Edward Peter Stringham is President of the American Institute for Economic Research,  Davis Professor of Economic Organizations and Innovation at Trinity College, and Editor of the Journal of Private Enterprise. He is editor of two books and author of more than 70 journal articles, book chapters, and policy studies. His work has been discussed in 15 of the top 20 newspapers in the United States and on more than 100 broadcast stations including MTV. Stringham is a frequent guest on BBC World, Bloomberg Television, CNBC, and Fox. Rise Global ranks Stringham as one of the top 100 most influential economists in the world. He earned his B.A. from College of the Holy Cross in 1997, his Ph.D. from George Mason University in 2002. His book, Private Governance: Creating Order in Economic and Social Life, is published by Oxford University Press.