The Covid turning point: when did the pandemic become unstoppable?

Pandemics, it has been said, are lived forwards but only understood backwards.

At the end of a year in which Covid-19 has claimed 1.7 million lives since it was first identified in the Chinese city of Wuhan last December, experts are now wondering if, and when, there was a turning point when the spread of the disease became globally unstoppable.

And about lessons for the future.

The stories they tell, sometimes conflicting, have one thing in common: a sudden realisation early in scientific circles that this was the long predicted “big one” and how they encountered feet of clay in policy circles geared primarily to respond to a flu pandemic, not a novel coronavirus.

While some have argued that the epidemic’s spread was, by its very nature, exponential and unpredictable in its dynamics, others point to missed opportunities at multiple points soon after Covid-19’s first emergence in China as it began to make incursions elsewhere.

William Hanage, associate professor of epidemiology at Harvard’s Chan school of public health, recalls his personal “gulp moment” at the beginning of the year.

“The first time I used the word pandemic was January 28, in a message to a friend. The World Health Organization had just declared a public health emergency of international concern, and I remember thinking if it had been H1N1 [influenza] it would already have been called a pandemic.

“The word itself doesn’t have a lot of practical force, but it has a lot of power to educate the public to take action. That delay wasn’t helpful.

“Even then we were seeing evidence of transmission outside China. Multiple transmissions. I knew when the first two cases were announced in Iran followed rapidly by news of deaths that we were in for a rollercoaster ride.

“I’d been in a meeting. People were talking about the severity. I was talking about people coughing on planes. Someone finished my sentence … ‘then people dropping dead’.”

Hanage adds: “The first rule of good pandemic management is that you have to be straight with people. Tell it quite bluntly. Those kind of statements were necessary but were pretty much ignored by public health officials who continued to play down the risks well into March.”

Looking back, Hanage is most surprised by the lack of concrete efforts in many countries, including the US and the UK, to grapple more effectively with the initial spread of infections at the earliest stage at a point when those efforts might have had the most practical impact.

For Hanage, however, the biggest missed opportunity was how other countries responded to the outbreak in northern Italy that rapidly took hold, the first serious outbreak in Europe.

“The breaking point as far as I can see was the failure of other countries to pay attention to what was happening in Italy.”

Even now Hanage still detects the same cognitive dissonance in policy circles and among individuals.

“Not much has changed. People still seem to find reasons why it doesn’t apply to them, why their country is different, or that they are different when they do need go home for Thanksgiving and spend a lot of time with people.”

If one thing is clear, it is that even if experts remain divided about the details of the early transmissions – a subject that has become the source of sometimes heated debate – scientists do agree that chances were missed.

A paper published in Science by Michael Worobey and colleagues in October tracking the virus’s evolution suggests that, contrary to some narratives, some early efforts in Europe and the US may have been far more effective at “extinguishing” the first emerging clusters than was understood at the time.

“Our results,” the paper said, “suggest that rapid early interventions successfully prevented early introductions of the virus from taking hold in Germany and the United States. Other, later introductions of the virus [fresh undetected infections coming in] from China to both Italy and Washington state, United States, founded the earliest sustained European and North American transmission networks.”

Among those later introductions – which had the effect of undercutting that early success – Worobey points to “several major travel events”, including the Trump administration’s decision to repatriate some 40,000 US residents from China, even as he ordered a ban on Chinese entry to the US in February.

That led, says Worobey, to one of the “serial, multiple introductions [of the virus that] triggered the major outbreaks in the United States and Europe that still hold us in the grip of control measures”.

Put another way, public health officials drew the wrong lessons about what was possible to counter the disease as they were blindsided by new infections coming into their countries.

While Peter Forster, at Cambridge University, who has done his own analysis of the spread of the virus through its history of mutation, disagrees with Worobey’s specific timeline, proposing a different route for infections, the conclusions that he draws are similar.

Like Hanage and Worobey, he believes much more effective action, particularly tracing at the very earliest stage, might have made a difference.

“I sent a message to Chris Whitty suggesting this very early on. But didn’t get an answer. A few weeks later it was all over the place.

“What made me believe it was serious in the middle of January was looking at the ratio of deaths to recoveries in China. Now we now know that there was underreporting of asymptomatic cases, but that should have been a warning.”

What has become clear to all is that both monitoring of respiratory diseases and a wider mindset that had been for too long focused on an influenza outbreak as the most likely source of “the next pandemic” needs to change.

“My expertise is tracking how viruses develop,” says Forster. “I would say you should have very regular monitoring of how the virus is mutating.”

Worobey and his colleagues came to a similar conclusion. “Our findings highlight the potential value of establishing intensive, community-level respiratory virus surveillance architectures, such as the Seattle Flu Study, during a pre-pandemic period.

“The value of detecting cases early, before they have bloomed into an outbreak, cannot be overstated in a pandemic situation.”

For Hanage the lesson is broader still. “People make mistakes,” he says, describing the missteps early in the response. “It’s not learning from them that’s unforgivable.”