Coronavirus challenge

Virus challenge

Print edition : April 10, 2020

Health workers spray disinfectant as a precautionary measure against COVID-19 in a residential area in Jammu on March 14. Photo: CHANNI ANAND/AP

A woman watches from a waiting area as a nurse administers a novel coronavirus test at a testing booth outside Yangji Hospital in Seoul on March 17. The hospital has introduced phone booth-style coronavirus testing facilities that avoid medical staff having to touch patients directly. Photo: Ed JONES/AFP

The deceptively small number of COVID-19 cases (and deaths) in India should not drive the nation into complacency: it needs to be prepared for a massive spread of the pandemic disease.

ON December 31, 2019, China reported to the World Health Organisation (WHO) the detection of a number of cases of an atypical pneumonia from an unknown cause in the city of Wuhan in Hubei province, ground zero of what has now spread worldwide to be a true pandemic. Eleven weeks afterwards, this previously unknown infection (“Evolving epidemic”, Frontline, February 28), now called COVID-19 (for novel coronavirus disease 2019), has afflicted over two lakh individuals and consumed over 8,500 lives across 168 countries spanning five continents. China alone accounts for over 81,000 of these cases, followed by Italy with over 35,000 cases. (As on March 19, the number of cases and deaths stood at 2,09,839 and 8,778 respectively.)

Scientists are still searching for the exact epidemiological reason for this unprecedented rapid escalation in the number of cases across the globe, particularly in Italy where cases have mounted at an alarming rate.

The case log in Italy has jumped from a single-digit figure to this five-figure mark in just under a month beginning February 20, overwhelming the country’s resources so much that doctors and hospitals are having to make the morally difficult ethical choice of prioritising who should be extended intensive care and who should be denied.

Even as the WHO assessed the situation on March 11 (when there were 1,18,319 cases and 3,162 deaths spread over 114 countries) and declared COVID-19, caused by a previously unknown virus belonging to the coronovirus family (which has now been renamed SARS-CoV-2 from its earlier 2019-nCoV), to be a pandemic, the daily increase in the number of cases in China had dropped from over 3,000 to one-hundredth that figure in just one month. “[M]ore than 90 per cent of cases are in just four countries [China, Italy, Iran and South Korea] and two of those—China and South Korea—have significantly declining epidemics,” WHO Director-General Dr Tedros Adhanom Ghebreyesus said while declaring the pandemic. The epicentre of the continually growing global epidemic has now moved from China to Europe, with Italy and Spain emerging as the new hotspots.

Unprecedented measures in China

Extraordinary situations call for extraordinary steps. On January 23, with China accounting for 571 of the 581 worldwide cases of COVID-19 (66 per cent from Hubei province alone) and with the epidemic threatening to become huge, the Chinese authorities imposed unprecedented measures to curb the spread of the novel viral infection, some of which like those on travel restrictions could be even viewed as going against the WHO’s advisories. Not surprisingly, China’s strategies gave rise to controversy, with some steps even being termed draconian.

Movement in and out of ground zero, Wuhan and 15 other cities in Hubei province, was blocked. Travel by all modes was severely curtailed. People in many Chinese cities were advised to stay home. According to The New York Times, nearly half of the people of the country were confined to their homes. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases of the United States’ National Institutes of Health, noted at that time that China’s extreme approach could work in the given context of rapidly escalating spread of infection.

Two months after such extensive lockdowns, some of which are still in place, the daily increase in the number of cases has now drastically reduced. So the question is whether these extraordinary but controversial measures were key to containing the epidemic and what lessons they offer to countries that are still on the upward slope of the epidemic and which of China’s non-pharmaceutical interventions were really instrumental in flattening the curve and taking the country on a downward slope.

Assuming that each infected person would infect two others (a reproduction number, or R0, of 2), early models of the disease’s spread that did not take into account such drastic measures estimated that the virus would infect nearly 40 per cent of the country’s population. But, according to Adam Kucharski of the London School of Hygiene & Tropical Medicine, who has been quoted in Nature online, the R0 had an amazing drop to 1.05 between January 16 and 30, a period that included the first week of lockdowns.

On February 28, the report of a WHO-China Joint Mission on COVID-19, which comprised 25 national and international experts, made the following observation: “In the face of a previously unknown virus, China has rolled out perhaps the most ambitious, agile and aggressive disease containment effort in history. The strategy that underpinned this containment effort was initially a national approach that promoted universal temperature monitoring, masking, and hand washing. However, as the outbreak evolved, and knowledge was gained, a science and risk-based approach was taken to tailor implementation. Specific containment measures were adjusted to the provincial, county and even community context, the capacity of the setting, and the nature of novel coronavirus transmission there.”

It went on to say: “The remarkable speed with which Chinese scientists and public health experts isolated the causative virus, established diagnostic tools, and determined key transmission parameters, such as the route of spread and incubation period, provided the vital evidence base for China’s strategy, gaining invaluable time for the response…. China’s bold approach to contain the rapid spread of this new respiratory pathogen has changed the course of a rapidly escalating and deadly epidemic… China is already… working to bolster its economy… even as it works to contain the remaining chains of COVID-19 transmission.”

However, questions have been raised in epidemiological circles about the efficacy of such lockdowns in handling the situation when the likely second wave of the epidemic surfaces as restrictions are lifted. It has been argued that such lockdowns prevent large sections of the population from being exposed to the virus and building up “herd immunity” within the community. How China phases, both spatially and temporally, the easing of restrictions in the weeks to come will be critical.

In this context, however, the report reassuringly said: “Appropriately, a science-based, risk-informed and phased approach is being taken, with a clear recognition and readiness of the need to immediately react to any new COVID-19 cases or clusters as key elements of the containment strategy are lifted [emphasis added].” The mission endorsed the belief of the Chinese authorities that it should soon be possible for the country to manage a resurgence in COVID-19 cases if that should occur once the restrictions are lifted “using even more tailored and sustainable approaches that are anchored in very rapid case detection, instant activation of key containment activities, direct oversight by top leadership and broad community engagement”.

In an interview to The New York Times, Bruce Aylward of the WHO, who led this mission, said: “… hundreds of thousands of people in China did not get COVID-19 because of this aggressive response”. According to him, China’s counter-attack can be replicated, “but it will require money, imagination and political courage”. Added to this was nationwide people’s commitment. “There was tremendous sense of ‘We’ve got to help Wuhan’, [and] not ‘Wuhan got us into this’. Other provinces sent 40,000 medical workers, many of whom volunteered,” Aylward said.

But there is criticism that China’s slew of measures came only after an initial phase of opaqueness about the epidemic and authoritarian dealing with any attempt by individuals trying to speak out about cases of a mysterious infection and the real ground situation, which perhaps led to a delay of two to three weeks in taking steps to contain the growing epidemic. “The delay of China to act is probably responsible for this world event,” Nature.com quoted Howard Markel, a public health specialist at the University of Michigan in Ann Arbor.

Asymptomatic cases drove rapid spread

A study published in Science on March 16 suggests that undocumented mild and asymptomatic cases of infection during the early phase of the epidemic in China before travel restrictions and other isolation measures were put in place drove its rapid spread across the country. The study used data on people’s movement between 375 Chinese cities between January 10 and 23, focussing particularly on the time leading up to the Chinese lunar new year, to simulate how SARS-CoV-2 spread across China and has estimated that these account for 86 per cent of all infections.

According to the study, while these undetected cases were only half as infectious as the known cases, the large number of such cases out there became the source for over 80 per cent of the diagnosed infections across the country. It is thus the undocumented cases that drove the spread and growth of the outbreak, at least in the initial phase, as per the study. The researchers also found that the tide turned following the travel curbs, self-quarantine and physical distancing advisories and widespread testing implemented on January 23 and thereafter, and documented cases accounted for 65 per cent of all infections.

Clearly, asymptomatic transmission has indeed occurred in China and is presumably occurring in other parts of the world as well. “Depending on their contagiousness and numbers, undetected cases can expose a far greater portion of the population to the virus than would otherwise occur,” said Jeffrey Shaman, one of the authors of the study. “These stealth transmissions will continue to present a major challenge to the containment of the outbreak going forward,” he added, an observation that should hold good for other affected countries as well.

According to a model simulation carried out by scientists at the University of Southampton, which Nature.com reported, if China had implemented its control measures three weeks earlier than January 23, it could have prevented 67 per cent of all cases there and would have cut the global number of cases to 5 per cent of the total. A study on the containment measures used in 296 Chinese cities says that cities that suspended public transport and banned public gatherings and events before their first cases showed up had 37 per cent fewer cases than cities that did not implement such measures speedily.

Several studies on the travel bans suggest that these did slow down the disease spread initially but not for long. According to a study published in Science in early March, banning travel in and out of Wuhan on January 23 delayed its spread to the rest of China only by three to five days. But it had a larger immediate impact on the international spread of the virus; there were 77 per cent fewer cases imported from mainland China than would have been expected otherwise. However, this only delayed the international spread by a few weeks because by mid February importation from other places in China, like Shanghai and Beijing, where the virus had got established, resulted in a rise in the global spread.

According to the study, even blocking 90 per cent of travel slows down the spread only by a matter of weeks on its own unless other measures are implemented. Of course, many countries across the world, including India, have now imposed severe travel restrictions. Their success in containing the spread will depend on the attendant national measures, such as widespread diagnostic testing, detection and isolation of confirmed cases, effective advisories for self-quarantine in suspected cases, physical distancing among the asymptomatic and avoidance of gathering of people.

So, does China’s aggressive approach, and its apparent success at stemming the spread of COVID-19, provide any lessons for other countries? Are lockdowns and travel bans the answer? Even as Italy and Spain, confronted with massive surges in the number of cases and deaths—Italy, with over 4,000 deaths, has overtaken China’s death toll of 3,242—imposed partial or total lockdowns in their different regions, it would be difficult to implement China-like measures given the latter’s political system. Elsewhere, adherence to such measures can only be voluntary. The high fatality rate in Italy (8.3 per cent compared with China’s current average of 4 per cent) is perhaps attributable to the high fraction of people above 65 years of age, who, as has become clear, are more vulnerable to COVID-19 than younger age groups. According to another commentary, the familial setting one obtains in much of Italy, where the very young, who can be asymptomatic carriers of the virus and can unwittingly transmit the infection, mingle and interact with the aged could be another contributing factor to the high mortality rate in Italy.

“Much of the global community,” noted the WHO-China Joint Mission report, “is not yet ready, in mindset and materially, to implement the measures that have been employed to contain COVID-19 in China. These are the only measures that are currently proven to interrupt or minimise transmission chains in humans. Fundamental to these measures is extremely proactive surveillance to immediately detect cases, very rapid diagnosis and immediate case isolation, rigorous tracking and quarantine of close contacts, and an exceptionally high degree of population understanding and acceptance of these measures [emphasis added].”

Actually, the observation made by the report (in bold above) is somewhat off the mark. The successes in South Korea and Singapore, the sizes of these countries notwithstanding, offer excellent examples of how measures (in italics above) can be effectively and efficiently deployed to contain the outbreak in other settings. From the peak of 909 cases on February 29, South Korea, a country of 50 million people (very small compared with China or India), has brought the number of daily cases down to about a tenth, and it has done so without taking any authoritarian measures or locking down towns and cities.

The reason for the Korean success has been the world’s most expansive and meticulously planned and organised testing programme, followed by effective isolation of confirmed cases and tracing and quarantining their contacts. According to www.ourworldindata.org, which compiles data from official and other published sources, South Korea has tested more than 2,80,000 people, that is, nearly 5,700 tests per million population, which is more than any other country. In comparison, India (as of March 19) has carried out tests on 14,175 samples (from 13,285 individuals), which works out to a meagre 11.7 tests per million people. This is far fewer than what many other neighbouring countries, such as Thailand (about 120/million) and Vietnam (40/million), have managed to achieve.

This suggests that the number of confirmed cases in South Korea is closer to the total number of cases than in other countries, notes the website. South Korea’s experience shows that diagnostic capacity at scale, case isolation and contact tracing are key to epidemic control. After SARS-CoV-2 emerged in China, South Korea ramped up its manufacturing capacity quickly in collaboration with manufacturers after the first kit was approved on February 7. A similar strategy has been adopted by Singapore too, which has been in a state of advanced readiness, including availability of hospitals, beds and adequate intensive care and quarantine facilities, so that the situation does not become unmanageable at any point of time.

The Indian situation

The Indian situation, with just 256 cases (and four deaths) as per the Union Health Ministry data of March 21, might seem comforting, but as epidemiologists and health experts have pointed out, this could be a big illusion arising out of the abysmally low level of diagnostic testing based as it is on some minimalist criteria of testing individuals only if they develop COVID-19’s classic symptoms even if they have been identified by contact tracing or had a history of travel to countries with the epidemic and are, therefore, potential carriers of the virus even though currently asymptomatic. Increasingly, studies and modelling efforts by scientists point to a much greater role played by asymptomatic carriers of the virus in the spread of the epidemic around the world.

Ramanan Laxminarayan of the U.S.-based Centre for Disease Dynamics, Economics & Policy said in a piece he wrote for The Hindu: “Testing is the most important thing we could be doing right now…. We need to identify coronavirus-infected patients in a timely manner in order to increase our chance of preventing secondary infections. There is no shame in admitting that we have far more cases than what we have detected so far…. If widespread testing were to commence in India, the number of confirmed cases would likely climb to the thousands very quickly.”

“If the projections from Europe,” he wrote, “are applicable in India… the prevalence rate would be upwards of 20 per cent.” This amounts “to about 200-300 million cases of COVID-19 infections and about four and eight million severe cases of the kind that are flooding hospitals in Italy and Spain at the moment”. He also warned that the infrastructure of the country’s health care system, such as the number of intensive care unit beds and ventilators, was inadequate.

T. Sundararaman, former Director of the National Health Systems Resource Centre, New Delhi, made similar observations in an interview to HuffPost India recently. The narrow criteria for testing make it more or less mandatory to test only those who walk in feeling unwell or feverish. “It is a self-fulfilling prophecy. You are actually not being able to detect whether community spread is happening or not. There is no reason why India will not have community spread.” According to him, instead of the current 61 testing centres, there should at least be 10 times that number; there should be at least one testing centre for each district. “[It] is true that you cannot test every fever. But any fever with respiratory symptoms suggestive of early pneumonia, shortness of breath, should be tested. You should not wait for a contact relationship. You should be offering the test much more widely now,” he said.

So, the illusory small number of COVID-19 cases (and deaths) in India, and the comforting statistic that there were a lower number of cases and deaths in the country in the SARS-CoV-1 and H1N1 epidemics compared with other parts of the world, should not drive the nation into complacency. Historical comparisons are good when the arguments are compelling. In the present case, they are not. SARS-CoV-2, with its much higher contagiousness and infectivity even from asymptomatic carriers, seems to be a different beast compared with other coronaviruses. Moreover, scientists are yet to fully unravel the science of the virus and the disease.

The country, therefore, needs to be prepared for a rapidly mounting number of cases to the tens of thousands and more, which does not seem to be the case from available evidence. As Laxminarayan wrote: “This is how epidemics move and the real numbers should spur us into positive action.” The prognosis for India by these experts holds an important message for the health authorities. One hopes that someone is listening, and it is high time that health measures besides shutdowns and travel restrictions are put in place.

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