H5N1

Multiomic characterisation of the long-term sequelae of SARS survivors: A clinical observational study

Thanks to @OmegaMom for providing the link to this February report in eClinicalMedicine: Multiomic characterisation of the long-term sequelae of SARS survivors: a clinical observational study. SARS affected far fewer people than COVID-19, but survivors were very much at risk of long SARS. The summary:

Background  

We aimed to characterise the long-term health outcomes of survivors of severe acute respiratory syndrome (SARS) and determine their recovery status and possible immunological basis.  

Methods  

We performed a clinical observational study on 14 health workers who survived SARS coronavirus infection between Apr 20, 2003 and Jun 6, 2003 in Haihe Hospital (Tianjin, China). Eighteen years after discharge, SARS survivors were interviewed using questionnaires on symptoms and quality of life, and received physical examination, laboratory tests, pulmonary function tests, arterial blood gas analysis, and chest imaging. Plasma samples were collected for metabolomic, proteomic, and single-cell transcriptomic analyses. The health outcomes were compared 18 and 12 years after discharge. Control individuals were also health workers from the same hospital but did not infect with SARS coronavirus.  

Findings  

Fatigue was the most common symptom in SARS survivors 18 years after discharge, with osteoporosis and necrosis of the femoral head being the main sequelae. The respiratory function and hip function scores of the SARS survivors were significantly lower than those of the controls. Physical and social functioning at 18 years was improved compared to that after 12 years but still worse than the controls. Emotional and mental health were fully recovered.  

Lung lesions on CT scans remained consistent at 18 years, especially in the right upper lobe and left lower lobe lesions. Plasma multiomics analysis indicated an abnormal metabolism of amino acids and lipids, promoted host defense immune responses to bacteria and external stimuli, B-cell activation, and enhanced cytotoxicity of CD8+ T cells but impaired antigen presentation capacity of CD4+ T cells.  

Interpretation  

Although health outcomes continued to improve, our study suggested that SARS survivors still suffered from physical fatigue, osteoporosis, and necrosis of the femoral head 18 years after discharge, possibly related to plasma metabolic disorders and immunological alterations.

China beat COVID-19 with science and strong public health measures, not just with authoritarianism

Via The Conversation, an article by Elanah Uretsky, an associate professor of international and global studies at Brandeis: China beat the coronavirus with science and strong public health measures, not just with authoritarianism. Excerpt:

I live in a democracy. But as Thanksgiving approached, I found myself longing for the type of freedom I am seeing in China.  

People in China are able to move around freely right now. Many Americans may believe that the Chinese are able to enjoy this freedom because of China’s authoritarian regime. As a scholar of public health in China, I think the answers go beyond that.  

My research suggests that the control of the virus in China is not the result of authoritarian policy, but of a national prioritization of health. China learned a tough lesson with SARS, the first coronavirus pandemic of the 21st century. 

How China flattened its curve 

Barely less than a year ago, a novel coronavirus emerged in Wuhan, China, with 80,000 cases identified within three months, killing 3,000 people. 

In late January 2020, the Chinese government decided to lock down this city of 11 million people. All transportation to and from the city was stopped. Officials further locked down several other cities in Hubei Province, eventually quarantining over 50 million people. 

By the beginning of April, the Chinese government limited the spread of the virus to the point where they felt comfortable opening up Wuhan once again. 

Seven months later, China has confirmed 9,100 additional cases and recorded 1,407 more deaths due to the coronavirus. People in China travel, eat in restaurants and go into theaters, and kids go to school without much concern for their health. Juxtapose that to what we are experiencing in the U.S. To date, we have confirmed over 11 million cases, with the last 1 million recorded in just the last one week alone. 

In September and October, friends from China sent me pictures of food from all over the country as they traveled around to visit friends and family for the mid-autumn festival and then the seven-day National Day vacation week. I envied them then and envy them even more now as Americans prepare and wonder how we will celebrate the holidays this year. 

What China learned from SARS 

We Americans are told that the freedoms Chinese now enjoy come at the expense of being subject to a set of draconian public health policies that can be instituted only by an authoritarian government. But they also have the experience of living through a similar epidemic. 

SARS broke out in November of 2002 and ended in May of 2003, and China was anything but prepared for its emergence. It didn’t have the public health infrastructure in place to detect or control such a disease, and initially decided to prioritize politics and economy over health by covering up the epidemic. This didn’t work with such a virulent disease that started spreading around the world. 

After being forced to come to terms with SARS, China’s leaders eventually did enforce quarantine in Beijing and canceled the week-long May Day holiday of 2003. This helped to end the pandemic within a few short months, with minimal impact. SARS infected approximately 8,000 worldwide and killed about 800, 65% of which occurred in China and Hong Kong. 

The Chinese government learned from SARS the important role public health plays in protecting the nation. Following SARS, the government improved training of public health professionals and developed one of the most sophisticated disease surveillance systems in the world. While caught off guard for this next big coronavirus outbreak in December 2019, the country quickly mobilized its resources to bring the epidemic almost to a halt inside its borders within three months.

Comparing SARS-CoV-2 with SARS-CoV and influenza pandemics

Via The Lancet Infectious Diseases, a personal view: Comparing SARS-CoV-2 with SARS-CoV and influenza pandemics. The summary:

The objective of this Personal View is to compare transmissibility, hospitalisation, and mortality rates for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with those of other epidemic coronaviruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), and pandemic influenza viruses. 

The basic reproductive rate (R0) for SARS-CoV-2 is estimated to be 2·5 (range 1·8–3·6) compared with 2·0–3·0 for SARS-CoV and the 1918 influenza pandemic, 0·9 for MERS-CoV, and 1·5 for the 2009 influenza pandemic. SARS-CoV-2 causes mild or asymptomatic disease in most cases; however, severe to critical illness occurs in a small proportion of infected individuals, with the highest rate seen in people older than 70 years. 

The measured case fatality rate varies between countries, probably because of differences in testing strategies. Population-based mortality estimates vary widely across Europe, ranging from zero to high. Numbers from the first affected region in Italy, Lombardy, show an all age mortality rate of 154 per 100 000 population. Differences are most likely due to varying demographic structures, among other factors. 

However, this new virus has a focal dissemination; therefore, some areas have a higher disease burden and are affected more than others for reasons that are still not understood. Nevertheless, early introduction of strict physical distancing and hygiene measures have proven effective in sharply reducing R0 and associated mortality and could in part explain the geographical differences.

COVID-19 origin research hit by political agendas: Zhong Nanshan

Via the South China Morning Post: Coronavirus origin research hit by political agendas, China’s ‘Sars hero’ says. Excerpt:

In an exclusive, wide-ranging interview with the Post, veteran Chinese infectious disease expert Zhong Nanshan shares his insights into the global battle to control the Covid-19 pandemic. In this third part of a four-part series, Zhong says the blame game between the US and China is putting important research at risk at a time when the world’s scientific community needs to join hands and work together.

 

The politicisation of the Covid-19 pandemic could stall vital global scientific cooperation into an investigation of its origins, according to China’s most respected respiratory expert. 

 

Zhong Nanshan, 83, known as a “Sars hero” for his role in fighting the 2002-03 severe acute respiratory syndrome epidemic, said scientists around the world needed to team up to establish where the new coronavirus, which causes Covid-19, had come from. 

 

Zhong, from the Chinese Academy of Engineering and a senior adviser to the government in its drive against Covid-19, said he had been approached by Ian Lipkin, the US epidemiologist, to use molecular tools to establish how the virus jumped to humans but the endeavour could be stalled for fear it would be distorted by political agendas.

 

Lipkin, professor of epidemiology at Columbia University, was an adviser on the film Contagion and himself contracted Covid-19. His association with Zhong dates back 17 years when they worked together on the Sars outbreak in China.  

 

Lipkin has been working since 2018 with professor Lu Jiahai’s team at Sun Yat-sen University’s public health school in Guangzhou, southern China, on emerging infectious diseases. They have been trying to establish the origin of the new coronavirus since February. Zhong, Lu and Lipkin met in Guangzhou in January and are in regular contact. 

“Professor Lipkin has a very good technology, called molecular capture, which can capture and analyse the key gene to identify the source of the virus,” Zhong said. “It will be a large amount of work that involves not only drawing [human] blood but also blanket investigation into animals.”

 

But Zhong said US politicisation of the pandemic, which aimed to lay blame on China, was putting the project at risk. “[Origin tracing] should have been an important scientific issue that called for joint research and I am all for it but now, with the political labelling, it is very difficult to do so,” he said. 

 

US President Donald Trump and Secretary of State Mike Pompeo have claimed, without evidence, that the virus escaped from a laboratory in Wuhan — the central Chinese city where the first cases were reported — and called for an investigation into the outbreak. They have also blamed China’s initial handling of the outbreak for causing the spread of the disease around the world.

 

China has rejected the claims and accused the US of spreading unfounded conspiracy theories. Beijing has repeatedly said it opposes politically-driven investigations into the origin of the coronavirus and would accept objective and science-based probes within the framework of the World Health Organisation, when the epidemic has waned. 

 

Zhong said the Chinese government had investigated the claims about the Wuhan laboratory and found no improprieties. “After the US made the allegations, the Chinese Centre of Disease Control and Prevention and the National Health Commission sent a special team to investigate the Wuhan Institute of Virology for two weeks,” he said. “The investigators found nothing improper and there was nothing that could show [the coronavirus] was manufactured by the laboratory. We also know that, based on their manpower, technological capability, and finance, it is just impossible for them to have manufactured it (the virus).”  

 

Available evidence suggests bats were the reservoir host for the new coronavirus which then possibly passed through an animal intermediary host to humans. Wuhan’s Huanan Seafood Wholesale Market – where wild animals were traded and which was linked to 27 of the 41 early cases – was initially believed to be the source of infection. However, epidemiologists had found only traces of the virus in samples taken at the market.

 

In addition, Zhong said, the first known case of the coronavirus in Wuhan, as well as most of 1,099 cases nationwide with links to Wuhan that were studied in January, had no connection to the market at all. Zhong said investigations into the origins of the coronavirus were important for preparing for the next outbreak, as there had already been three this century – Sars in 2002, Middle East respiratory syndrome (Mers) in 2015 and now Covid-19. But, he said, investigations should cover other countries as well as China. 

 

“We need to find out exactly how the virus transmitted,” he said. “It’s a process of evolution and that can happen anywhere. Data showed it happened in China, France and the United States. We really need to find out how this happened.” Zhong said it was now established that the earliest cases had occurred in September and November.

 

“It occurred in November in the US and also in France and Italy, so it’s a world problem that the virus might have existed long before [it was reported in China],” he said.

China’s top virus warrior ‘shocked’ by US COVID-19 death toll

Via the South China Morning Post, the second in a four-part interview with Dr. Zhong Nanshan: China’s top virus warrior ‘shocked’ by US coronavirus death toll. Zhong pretty well bullied the Chinese Communist Party into admitting that SARS was a problem, and he hasn't mellowed with age. Excerpt:

The US death toll from the coronavirus pandemic has shocked the scientist leading the fight against the disease in China, with the respiratory disease expert attributing the magnitude of American fatalities to a failure by policymakers to heed scientists’ advice. 

More than 1.66 million Covid-19 infections have been reported in the US, with 98,226 people dying from the disease – the highest number of deaths for any country. In all, 5.49 million people have been infected globally and more than 340,000 have died, according to Johns Hopkins University. 

“Seventeen years ago, the Sars epidemic was handled so well in the US, completely differently from the situation now,” said Zhong Nanshan, 83, director of the National Clinical Research Centre for Respiratory Disease and the leader of a team of scientists advising the government. 

“You can say that [the US] carried out very extensive screening or more screening than other countries … But the heavy casualties still shocked me,” he said in an exclusive interview with the South China Morning Post. 

Zhong said his counterparts in the US told him that the American system was ill-prepared for the epidemic, despite the country’s high level of medical care, equipment and facilities. 

He said this was similar to the early response in Wuhan – the central Chinese city where the outbreak was first identified – when many medical personnel were infected and died. 

But the main problem in the US was the failure to listen to medical experts, he said. As a result, US President Donald Trump “underestimated the disease’s infectious power as well as its harmful nature. He thought it was a big flu.” 

US officials also did not listen to medical experts’ views concerning the reopening of the economy, he said. 

“Opening the economy quickly can be risky. I think they should follow the rules of science and reopen the economy step by step,” Zhong said. 

Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, has cautioned against businesses reopening too soon because of the threat of a second wave of infections. 

Fauci, who is the government’s top medical specialist, has said repeatedly that “the virus will decide when the country is to open back up”. Some Trump supporters have attacked Fauci for these comments, suggesting he should be removed from the White House’s coronavirus task force. 

“Of course, [the economy] is very important for any country, but this problem [of striking a balance] has not been handled well, and that’s another reason” for the pandemic’s impact in the US, said Zhong, who often has been compared to Fauci. 

He said the US had stumbled this time, while it successfully nipped severe acute respiratory syndrome (Sars) in the bud 17 years ago. 

Zhong said he was in touch with US experts who went on high alert after Sars broke out in early February 2003. 

“So they knew [what happened] in China. I told them that a contagious disease of unknown cause [is spreading] and they needed to watch out,” he said. 

“Because of the strong preventive actions taken, the US only had 27 [Sars] cases … that is completely different from what’s happening now.” 

The respiratory disease specialist also noted that Sars happened two years after the September 11, 2001 terrorist attacks in the US, which had driven the US to strengthen its public health and emergency systems. 

“After September 11, and as far as I know, investment in the US Centres for Disease Control and Prevention increased by 10 times,” he said. 

One thing Zhong said he was not surprised by was the spread of conspiracy theories related to the new coronavirus, recalling a visit to Seattle in 2003 where he saw a magazine with the headline: “Sars: China’s weapon for mass destruction”. 

“I don’t find them strange, because they were always there, and they have just resurfaced again 17 years later,” he said.

Coronavirus: China’s ‘SARS hero’ Zhong Nanshan urges Hong Kong to relax border controls with mainland and Macau

Via the South China Morning Post: Coronavirus: China’s ‘Sars hero’ Zhong Nanshan urges Hong Kong to relax border controls with mainland and Macau. Excerpt:

In an exclusive, wide-ranging interview with the Post, veteran Chinese infectious disease expert Zhong Nanshan discusses the origin of the new coronavirus, how Hong Kong has become a role model in containing Covid-19, why the United States has recorded a higher fatality rate than the city and how Asian countries should get prepared for a second wave of infections. In the first of a four-part series, Zhong urges the Hong Kong administration to revive the economy by easing border restrictions. 

A mutually recognised health system between Hong Kong and mainland China could enable cross-boundary travellers to skip mandatory Covid-19 quarantine and allow further relaxation of border restrictions, top Chinese infectious disease expert Zhong Nanshan says. 

In an exclusive interview with the Post, Zhong, dubbed a “Sars hero” by Chinese state media for his pivotal role in the country’s fight against the severe acute respiratory syndrome epidemic in 2002-03, also praised Hong Kong for its efforts to contain the new coronavirus and called for more cross-border interaction to reboot the city’s economy. 

Zhong said he would visit Hong Kong for further exchanges in August.

 “Hong Kong has done beautifully this time, totally different from how it did 17 years ago during Sars,” said Zhong, who now serves as director of the State Key Laboratory of Respiratory Disease. “[Relaxing quarantine] can be and should be done now.” 

His comments came after Secretary for Food and Health Sophia Chan Siu-chee told the Post earlier this month that officials were studying proposals on using an electronic health certificate to exempt residents from the 14-day quarantine when they visited Macau and Guangdong province in a bid to create a “travel bubble” to make it easier for people to move between regions.  

Zhong believed it could be done now. “I think Hong Kong and the mainland should also take this step and have a mutually recognised [system] … I don’t think it’s that essential to be isolated in Hong Kong for 14 days,” he said. “That’s because Hong Kong is facing a big economic problem.” 

The city’s economy slumped 8.9 per cent year on year in the first quarter, its worst contraction on record. 

The 83-year-old, who leads the National Health Commission task force investigating the coronavirus, in January visited the front line in Wuhan, where the virus was first reported. A regular voice of caution, he recently warned against a second wave of imported infections in mainland China as most people there did not have immunity. 

But in the interview, he argued the return to schools and workplaces in Guangdong and across the country had not caused huge problems, saying “it appears possible to cross the river by feeling the stones”.

Pulmonary fibrosis secondary to COVID-19: A call to arms?

Via The Lancet Respiratory Medicine, an alarming report: Pulmonary fibrosis secondary to COVID-19: a call to arms? Excerpt:

Other strains of the coronavirus family, namely severe acute respiratory syndrome coronavirus (SARS-CoV; known as SARS) and Middle East respiratory syndrome coronavirus (MERS-CoV; known as MERS), are genetically similar to SARS-CoV-2 and cause pulmonary syndromes similar to COVID-19. At the end of the SARS epidemic in June, 2003, 8422 individuals were affected and 916 died; whereas MERS, which was first identified in April, 2012, has infected 2519 individuals worldwide to date, including 866 deaths. 

The predominant CT abnormalities in patients with SARS included rapidly progressive ground glass opacities sometimes with consolidation. Reticular changes were evident approximately 2 weeks after symptom onset and persisted in half of patients beyond 4 weeks. However, a 15-year follow-up study of 71 patients with SARS showed that interstitial abnormalities and functional decline recovered over the first 2 years following infection and then remained stable. 

At 15 years, 4·6% (SD 6·4%) of the lungs showed interstitial abnormality in patients who had been infected with SARS. In patients with MERS, typical CT abnormalities included bilateral ground glass opacities, predominantly in the basal and peripheral lung zones. Follow-up outcomes are less well described in patients with MERS. In a study of 36 patients who had recovered from MERS, chest x-rays taken a median of 43 (range 32–320) days after hospital discharge showed abnormalities described as lung fibrosis in about a third of the patients. Longer-term follow-up of patients who recovered from MERS has not been reported. 

Pulmonary fibrosis can develop either following chronic inflammation or as a primary, genetically influenced, and age-related fibroproliferative process, as in idiopathic pulmonary fibrosis (IPF). Pulmonary fibrosis is a recognised sequel of ARDS. However, most follow-up studies—which have included both physiological measures and chest CT—have shown that persistent radiographic abnormalities after ARDS are of little clinical relevance and have become less common in the era of protective lung ventilation.

Available data indicate that about 40% of patients with COVID-19 develop ARDS, and 20% of ARDS cases are severe. Of note, the average age of patients hospitalised with severe COVID-19 appears to be older than that seen with MERS or SARS, which is perhaps a consequence of wider community spread. In inflammatory lung disorders, such as those associated with autoimmune disease, advancing age is a risk factor for the development of pulmonary fibrosis. Given these observations, the burden of pulmonary fibrosis after COVID-19 recovery could be substantial. 

Progressive, fibrotic irreversible interstitial lung disease, which is characterised by declining lung function, increasing extent of fibrosis on CT, worsening symptoms and quality of life, and early mortality,10 arises, with varying degrees of frequency, in the context of a number of conditions including IPF, hypersensitivity pneumonitis, autoimmune disease, and drug-induced interstitial lung disease. 

Although the virus is eradicated in patients who have recovered from COVID-19, the removal of the cause of lung damage does not, in itself, preclude the development of progressive, fibrotic irreversible interstitial lung disease. Furthermore, even a relatively small degree of residual but non-progressive fibrosis could result in considerable morbidity and mortality in an older population of patients who had COVID-19, many of whom will have pre-existing pulmonary conditions. 

At present, the long-term pulmonary consequences of COVID-19 remains speculative and should not be assumed without appropriate prospective study. Nonetheless, given the huge numbers of individuals affected by COVID-19, even rare complications will have major health effects at the population level. It is important that plans are made now to rapidly identify whether the development of pulmonary fibrosis occurs in the survivor population. By doing this, we can hope to deliver appropriate clinical care and urgently design interventional trials to prevent a second wave of late mortality associated with this devastating pandemic.

Coronavirus that causes COVID-19 can produce more than three times as many pathogens as SARS strain, HKU study reveals

The more we learn about this virus, the less there is to love. Via the South China Morning Post: Coronavirus that causes Covid-19 can produce more than three times as many pathogens than Sars strain, HKU study reveals. Excerpt:

The coronavirus that causes Covid-19 can produce more than three times the amount of pathogens than the strain that caused the severe acute respiratory syndrome (Sars) outbreak in 2003, although patients may display less inflammatory and immune responses, a study has found. 

The finding from the research, led by prominent Hong Kong microbiologist Yuen Kwok-yung, is the first of its kind based on tests conducted on lung tissue removed from Covid-19 patients. The results underlined the virality of the disease, as well as difficulties for health authorities worldwide to detect it compared to Sars. 

It took about six months to contain the Sars epidemic. 

But it is a much bigger challenge for the Covid-19 pandemic, which has infected more than 1.6 million people around the world and caused more than 100,000 deaths in four months. According to the World Health Organisation, some 8,098 people were infected by Sars and 774 died of it.

“There is almost no possibility of containing the virus before July,” said Yuen, of the University of Hong Kong (HKU), who led the study published in the scientific journal Clinical Infectious Diseases. 

By infecting lung tissues, donated by six patients, with both the viruses, Yuen and his team found the new coronavirus, officially known as Sars-CoV-2, generated 3.2-fold infectious viral particles than Sars within 48 hours. 

“In some cases, Sars-CoV-2 could replicate by about 100 times within 48 hours, while the Sars virus may have peaked at about 10 to 20 times of replications,” Dr Chu Hin, research assistant professor from HKU’s medical school, said. 

Despite reproducing more efficiently, the new virus induced slower immune and inflammatory responses, according to the study. Unlike the Sars virus, the Sars-CoV-2 almost did not induce any signalling protein interferons within 48 hours, which is key in triggering the immune system to counteract against the virus.

BC’s top doctor wrote a book about fighting viruses in 2009

The Tyee has published my article: BC’s Top Doctor Wrote a Book about Fighting Viruses in 2009. Excerpt:

Soap and Water & Common Sense: The Definitive Guide to Viruses, Bacteria, Parasites, and Disease By Dr. Bonnie Henry House of Anansi, 2009. 

Dr. Bonnie Henry’s news conferences have become a part of daily life in B.C. When they attend her briefings, Premier John Horgan, Health Minister Adrian Dix, and Public Safety Minister Mike Farnworth fade into the background, at a safe distance from her and one another. They speak chiefly to endorse what their chief medical officer says. The contrast with Trump’s press conferences is impossible to miss. 

It certainly helps that Dr. Henry can deliver alarming news in a calm tone of voice, without relying on technical jargon; we pay attention, we absorb the news, but we don’t freak out. Treated like adults, we respond like adults.  

Those same communication skills are evident throughout her 2009 book Soap and Water & Common Sense, written years before she became B.C.’s provincial health officer. The book is now available with a new introduction, written in March, and the content itself is still very timely: while our healthcare system is fighting COVID-19, other diseases are going to exploit their opportunity.

COVID-19 has the potential to become as severe as the Spanish flu

Via Maclean's: COVID-19 has the potential to become as severe as the Spanish flu.

Timothy Sly is an epidemiologist and professor at the school of Public Health at Ryerson University. In 2003, he was involved in the management of SARS in Toronto.   

We are very likely heading toward the pandemic of the century.   

We have been preparing for it since 2003, when SARS revealed both our non-existent, early-warning systems and the inadequacy of our initial responses to a novel infectious disease. But the battle was fought well and when the dust settled, Canada had recorded 438 probable and suspect SARS cases, of which 44 had not survived, a 10 per cent case-fatality rate (CFR), similar to other SARS-affected countries. And like those other countries, we learned a lot, planned a lot, and in September 2004 the Public Health Agency of Canada was established.     

Pandemic planning was accelerated later that same year, when another communicable disease threat emerged in Southeast Asia: a deadly avian influenza virus. Since 2003, 400 out of the approximate 800 humans who have became infected from poultry have died, a CFR of 50 per cent, similar to untreated bubonic plague, untreated cholera, and Ebola hemorrhagic fever. Yes, you read that correctly; it’s an avian influenza virus with the antigen code H5N1 otherwise known as “bird flu.” Fortunately, it still is not capable of sustained spread person-to-person.

But the pandemic disease which killed more people in little over a year than any other in history, was the 1918 H1N1 avian influenza, sometimes erroneously called the “Spanish flu.” With a global case fatality of two to 2.5 per cent, it is estimated to have harvested at least 50 million people, with possibly many more in areas that were not keeping records. 

In case you are reaching for the keyboard to point out that the “Black Death,” or bubonic plague, killed many more than that, it’s not true. The plague killed a greater proportion of the world’s population at that time, but it took nearly a century to kill the same number as the 1918 flu did in about 15 months. Although the 1918 flu case-fatality rate was less than SARS, its transmission was much more effective, enabling it to reach the entire globe.    

We must now face the reality that COVID-19 may have the potential to become as severe as the 1918 influenza. The CFR of around 2 per cent has appeared to increase over the last couple of weeks to about 3.5 per cent, due in all likelihood to the logistic impossibility of recording the actual case numbers on a daily basis from a population of more than a billion with anything even remotely resembling accuracy and validity. 

By comparison, the cases occurring outside of China, which we can assume to have been made under greater scrutiny, were around 0.3 per cent fatal (up until Feb. 19 that is, when Iran first announced some clearly dubious and understated claims). 

COVID-19’s rate of spread globally shows no sign of slowing and of course it’s moving far faster than the Spanish flu in 1918, when it took an ocean liner about six days to travel from Southampton, England to New York, longer than the one-to-three-day incubation period of influenza. Today, viruses travel in comfort at 600 kilometres per hour and at 39,000 feet; they can be anywhere on the planet in 24 hours. The incubation period of COVID-19 can be two to 11 days, but usually six to seven days, and certainly long enough to be at the destination for several days before the first signs of illness are noticed.   

We can certainly pay tribute to the pandemic planning of the early 2000s, without which we might not have been able to contain the few dozen cases of COVID-19 that have arrived in Canada thus far, or prevent onward transmission through the community. But the odds are stacked against this scenario remaining unblemished.  

During the earliest stages of controlling the spread of any infectious pathogen, containment is key, involving finding and isolating sick individuals who meet the case definition, and quarantining their contacts. Theoretically, if this is immediate and flawless, it can be 100 per cent effective. But inevitably, we must expect “leakage” due to time delays, “hidden” cases such as asymptomatic and pre-symptomatic cases, defective case-definitions, and errors in logistics and reporting. 

Sooner rather than later, we will find cases with no known connection to foreign sources or indeed to any other known case. That will imply the existence of unknown infectious cases—stepping stones, if you like—who will already have infected others. When that happens, the scenario will inevitably change from simple “containment” to “mitigation.”    

We will still try to contain and isolate all cases while searching for asymptomatic or missing infectious individuals, but an uncontained spread will be a very real possibility at that stage. Mitigation at the individual, family or group level becomes top priority. 

Essentially, it’s a reversal of the containment principle and involves drawing a “healthy containment” circle around yourself, in a sea of possible infection, and hoping to stop the virus entering by using hygiene and distancing.