Exposure needs to be digitally traced Aggressive testing, tracing those infected is key: Korean envoy
Paradigm shift in who needs to be tested and traced and how need of the hour, as traditional methods might be too slow
nNEWDELHI: The spread of the coronavirus disease (Covid) is too rapid to be contained by the traditional manual contact tracing of infected people, a new study has concluded, calling for digital and phone-based methods to control the contagion at scale.
The study, conducted by professors at the University of Oxford and published in the journal Science, also flagged significant concerns around privacy and ethics and urged governments to be transparent and constitute an independent board to oversee the use of such invasive techniques.
“Our analysis suggests that almost half of coronavirus transmissions occur in the very early phase of infection, before symptoms appear, so we need a fast and effective mobile app for alerting people who have been exposed. Our mathematical modelling suggests that traditional public health contact tracing methods are too slow to keep up with this virus,” said Christophe Fraser of Oxford University’s Big Data Institute, Nuffield Department of Medicine, and one of the authors of the study.
The paper has been published at a time when India is experiencing a surge in infections – the number has almost tripled in five days – and governments have pressed the local police, district administrations and even antiterror squads to trace people who attended or have come into contact with those who attended an Islamic congregation in March in New Delhi’s Nizamuddin, which has emerged as the biggest hotspot of Covid-19 in the country.
In the study, scientists use a mathematical model of infectiousness through four routes of transmission: symptomatic (known contact with someone exhibiting Covid-19 symptoms), pre-symptomatic (contact with someone before symptoms showed up), asymptomatic (direct transmission from individuals who never experienced symptoms), and environmental (when direct close contact is not known).
In the model, the scientists assume that the threshold for stopping the spread of the epidemic is to reduce the reproduction number (R) – the number of people one patient can infect – to below one. This would mean that each Covid-19 patient would infect less than one person, and the disease would eventually die out. The model of infection spread is assumed to be exponential – as has been witnessed in several countries.
They found that instantaneous contact tracing significantly improved chances of containing epidemic and reducing R to below 1, while a delay of 3 days – typically associated with manual contact tracing – led to probability nearing zero. To be sure, this assumed that no other parameters – such as weather or medical intervention – were involved.
“At current stage of epidemic, contact tracing can no longer be performed effectively by public health officials in UK, and many countries across Europe, as coronavirus is spreading too rapidly. Our research of early data from other countries shows patient histories are incomplete - we don’t know who we sat next to on the bus,” said David Bonsall from Oxford’s Nuffield Department of Medicine and one of the authors.
The scientists suggested use of a mobile phone app that keeps a temporary record of proximity between individuals so that it can immediately alert close contacts of diagnosed cases and prompt them to self-isolate. The paper also proposed an algorithm by which instantaneous signals, carrying details of proximity and location, are transmitted to and from a central server, which also receives coronavirus diagnoses.
This enables recommendation of risk-stratified quarantine and physical distancing measures in those known to be possible contacts.
“To work, this approach needs to be integrated into a national programme, not taken on by independent app developers. If we can securely deploy this technology, the more people that opt-in, the faster the epidemic will stop, and the more lives can be saved,” Bonsall said.
But it flags significant ethical and privacy concerns and stresses need to avoid coercive surveillance. It calls for oversight by an independent board, a transparent algorithm, data protection and sharing of knowledge.
“People should be democratically entitled to decide whether to adopt this. The intention is not to impose technology as a permanent change to society, but we believe under these pandemic circumstances it is necessary and justified to protect public health,” the study said.
nNEW DELHI: Aggressive testing among those at high risk, tracing people infected by the Coronavirus and quarantining them is key to preventing the mass spread of Covid-19, South Korean ambassador Shin Bong-kil said.
South Korea’s 3T or “test, trace and treat” policy figured in Prime Minister Narendra Modi’s video conference with 130 Indian envoys on Monday as one of few successful approaches to tackle spread of the virus. Shin said the situation is his country had stabilised, with the number of new confirmed cases showing a steady decline and fluctuating around 100 a day. “The Korean government’s Covid-19 control strategy consists of robust testing to identify confirmed cases, tracing their contacts, and treating the infected at earliest possible stage,” Shin said in an interview with HT.
South Korea’s current diagnostic testing capacity is up to 15,000 tests per day. While it has done more than 400,000 tests, it continues to test at near-full capacity, he said. Identifying, isolating and treatment in early stages is only viable method as no vaccine is available, he said.
Asked if the 3T can be applied in India, which has a much larger population, he replied: “The lockdown of entire nation was necessary considering India’s sheer size and demographic. However, to prevent mass spread, it is important to identify those at high risk, carry out aggressive testing, then trace those infected and quarantine them.”
More than half of South Korea’s 9,600 cases were traced to the Shincheonji Church of Jesus, and Shin said his country had faced a mass outbreak in the initial stage “due to a gathering of a religious congregation” in a province. “The Korean government acquired the list of all members of and aggressively tested and quarantined. We were thus successful in controlling it early,” he said.
Shin said Korean government was prepared to share all information and insights with India. “President Moon Jae-in and PM Modi exchanged ideas through virtual G20 Summit,” he added.
In the long run, South Korea and India, with their advanced IT, bio and pharmaceutical industries, can cooperate in research and development in fight against virus-related diseases, he said.
Shin also hoped the Indian government takes speedy steps to address concerns of Korean firms once lockdown ends. “As you are well aware, Korean companies such as Samsung, LG, Hyundai and Kia closed their plants due to the lockdown…well aligned with the ‘Make in India’ policy, our companies have invested heavily here and a shutdown incurs massive losses for them,” he said.
“Once it is lifted, new personnel will have to be dispatched for handling new equipment and installing new facilities. I hope authorities expedite the visas.”
With hundreds of South Korean nationals stranded in India, Shin said a special Korean Air flight is expected to fly out those who wish, in first weekend of April. “Further evacuation will depend on future situation and status of shutdoww,” he said.