Testing and contact tracing are the tip of the spear in the fight against COVID-19. While other strategies to check the spread, such as social distancing, hygiene and use of masks are generalized and require universal action, which is difficult to achieve, testing and contact tracing are targeted and action required is centralized and therefore easier. A key challenge for countries with community transmission has been to rapidly ramp up their testing capacities, and countries that have struggled with it have seen some of the steepest growth of infections. For example, USA, which currently has the most number of infected cases and deaths, had a shortage of test kits up until mid-March, due to supply side issues.
Contact tracing is the process of identification of persons who may have come into contact with an infected person, so that they can be quarantined and monitored for symptoms. It can be conducted manually i.e. by interviewing an infected person, or digitally, using data from mobile phones. Governments have developed contact tracing apps, which use GPS data and Bluetooth networks to record proximity events between two phones running the app. Upon an individual’s COVID-19 diagnosis, contacts are instantly, automatically, and anonymously notified of their risk and asked to self-isolate. Contact tracing apps have proven to be the most effective method accomplishing the task.
Some key barriers and limitations impede the efficacy of testing and contact tracing
Shortage of testing kits have forced governments to restrict tests to highly likely cases, to be identified by doctors. Therefore, tests often require a medical referral, creating a significant barrier.
Access barriers such as cost, distance and timing continue to exist, excluding a large population from testing.
Testing and tracing is most feasible as an effective strategy at the start of an outbreak when there are just a few chains of transmission of the disease. But if this does not keep the epidemic under control, and there is widespread community transmission, there will quickly be many cases and contacts.
There are higher transmission risks around the time of symptom onset, followed by a lower transmission risk at the later stage of disease. Given the nonspecific and mostly mild symptoms of COVID-19 at presentation, patients are often identified and hospitalized at a later stage of disease when the transmissibility of infection has started to decrease.
Digital contact tracing requires both individuals in a proximity event to have the app on their phone for the event to be recorded. This means that for the contact tracing apps to have a meaningful impact, the rate of adoption of the app must be higher than the rate of spread of infection.
A large part of the population, especially in developing economies, do not have access to suitable smartphones and would not have access to these benefits through this route.
Another concern regarding contact tracing apps which require self reporting of symptoms and often even infection, is that of nefarious actors seeking to spread panic by falsely claiming to be infected.
What could be improved/is likely to work
Drive thru test centres and mobile test centres for outreach to marginalized areas can bridge the access gaps. A combination of telemedicine consultation and self-test kits that can be administered at home can further bridge the access gaps.
Free-of-cost tests or coverage under insurance plans can remove the cost barriers to testing.
Conditionality of medical referrals for tests should be removed, so that anyone with symptoms or exposure can get tested.
Equity concerns with regard to those who do not have access to suitable smartphones can be addressed by using manual interviews, text surveys and apps for basic phones as alternatives.
False reporting on contact tracing apps could be prevented by allowing only hospital workers to trigger the broadcast of infection status, though this trades away some of the privacy of diagnosed patients.
Strategies to increase the adoption of contact tracing apps:
App should be open source and audited by both security professionals and privacy advocates to build trust by assuring (i) privacy from snoopers, (ii) privacy from contacts, and (iii) privacy from the authorities.
Contact tracing app can be made a mandatory requirement for entering certain public places such as public transport, malls, airports, etc.
Incentives, such as a donation to a nominated charity, or free mobile phone credit, could be used to drive early adoptions.
Social proof can be leveraged to drive adoption. Contact-tracing apps, by design, know how many other people close by have the app installed. This number should be displayed prominently on the app so that a user may be incentivized and equipped to attempt to persuade others nearby to install the app, in the interest of public health.
Increase perceived relevance and value of the app by helping users/citizens assess the risk they are personally exposed to. While individuals are mindful of their strong ties (family and friends) well, there seem to be blind-spots when it comes to considering their weak ties interactions (strangers and acquaintances) in assessing the risk of being exposed to infection. The app might help to address this blindspot and reduce the optimism bias.
Communicate to public using mass media that effective contact tracing
a. would significantly reduce their personal risk, especially if they ensure that
their close contacts have the app.
b. would ultimately mean that they and everyone else will emerge from the
lockdown more quickly and safely.
c. would enable them to contribute to saving the lives of others, particularly
the vulnerable, and those in caring roles, both locally and globally. Appeals
to a sense of ‘we are all in this together’ of ‘solidarity’ may be effective.