Tim Spector: the data explorer who uncovered vital clues to Covid

When Tim Spector tells me that I probably had Covid-19 last March when I was days away from having a baby, it’s hard to ignore him. That’s because Spector is the man who informed the nation about the most predictive (and strange) symptom of Covid-19 last year: the loss of smell and taste.

He breaks the rather alarming news to me with such affability that I forget to retroactively panic. “Maybe your pregnancy protected you from having very extreme symptoms because your immune system would have been working well already,” he says, reassuringly.

Nevertheless, he is confident because, as he explains, losing my sense of smell and taste as I did during the first wave of the pandemic was a textbook symptom at the time and 90 per cent predictive of a positive Covid-19 test.

Spector knows this because he is the epidemiologist behind the Covid Symptom Study app, a reporting tool that is arguably the world’s largest ever citizen science experiment. The software, which was designed and launched in five days at the start of the pandemic in April 2020, was masterminded by a handful of doctors and scientists at King’s College London as well as the health science company Zoe, which Spector co-founded. (Many people call it the Zoe app because the start-up’s logo briefly appears on the software’s home screen.)

A week after the app was released, a million people had downloaded it, spurred on by a tweet from Stephen Fry. By the second week, that number had doubled. More than a year on, 4.6 million Britons have logged their symptoms. About a quarter continue to diligently self-report their health via the app every day.

The remarkable dataset gleaned from this project has become an unofficial national Covid-19 registry. It is large enough to provide scientifically accurate insights about how the virus is spreading and how it affects different types of people. It is an epidemiologist’s playground.

In return, Spector fed users with information they were initially starved of: how the virus was spreading in their neighbourhoods, symptoms to watch for and infection trends in the rest of the country. “People really wanted to help, it was a two-way process. It was therapy,” he tells me. “In that initial surge, they felt so let down by the government. They weren’t allowed to ring 111. All the GPs were closed. No one gave a damn, they thought. It was that mood, plus amazing altruism from many people.”

Spector has consistently been the first to publicise new symptoms that have emerged from the data throughout the course of the pandemic, including anosmia (loss of smell), confusion in the elderly and digestive issues in children last year. Using data from the app, he has published studies about the prevalence of long Covid, showing that one in 20 people are likely to experience symptoms beyond eight weeks.

The app has also shown it is possible to predict who will go on to develop long Covid, particularly those with multiple early symptoms, asthma and a higher body-mass index. Last month, it uncovered the most recent new symptom in vaccinated people, showing that they are now sneezing when they become infected.

In every case, Spector has sounded the klaxon far sooner and more loudly than the UK government and Public Health England, which have at times struggled to keep the public informed about the virus’s evolution. But Spector isn’t some sun-starved scientist or battered public health administrator.

Even in a pandemic that has made quasi-celebrities of figures who would otherwise have remained obscure, Spector cuts a different figure. The 63-year-old has the tanned, energetic look of an athlete on vacation. And that pretty much sums up how he lives life: constantly sprinting from one topic to the next, with long restorative breaks in between to travel, meditate, write his books (he’s written four and is working on a fifth) and do extreme sports. What he turns his attention to next — what happens when your breakfast hits your gut, say, or as yet unknown early signs of dementia — could have major consequences.

Restlessness is the defining characteristic of Spector’s career. He trained as a consultant rheumatologist, quickly got bored and wanted to move on to studying other conditions. But he couldn’t pick just one. So in 1992 he turned his hand to genetic epidemiology, the study of the genetic roots of all diseases from autism to cancer.

Since then, he has repeatedly reinvented himself, first as an epigeneticist, studying how the environment affects gene function, and later as an expert in the gut microbiome — the population of microbes that live harmoniously in our bodies — and its role in health and obesity. Before coronavirus, his interest in obesity led to a 12-year stint studying nutrition and the science of food, resulting in dozens of published papers, two books and the Zoe start-up.

“I always joke with Tim that it’s been five years, what’s coming up next?” says Deborah Hart, executive director of Spector’s lab at King’s College, who has known him since 1986 when their research careers began. “He would fly out to meetings all over the world, and he’d call me one day from somewhere like San Diego, saying, ‘Deb, I’ve met this guy, he’s got a brand-new assay and we need to send him 5,000 serum samples.’ Before any new wave would start, Tim would be there and discover it. That’s what makes him exciting to work for.”

Even in a pandemic that has made quasi-celebrities of figures who would otherwise have remained obscure, Spector cuts a different figure

Born and raised in north London, Spector seems to crave excitement. For example, he tells me that he started his career as a junior doctor on a medical ward in Brussels, where he had to speak French to all his patients — having never spoken it before, he says.

“I had to learn it very quickly. That’s part of my DNA. I like getting into something really new,” he says. He credits his genes again for his obsession with switching areas of research, saying it is part of an appetite for risk that he gets from his mother, an Australian physiotherapist.

It’s the same rush he gets from skiing, sailing, skydiving, white-water rafting and ocean swimming. Five years ago, he escaped death in a heli-skiing accident, running from a burning helicopter on the Georgia-Russia border. That hasn’t stopped him from returning to the sport. “I’m not crazy, but I take measured risks,” he says. His “measured risk” of the moment is microdosing on a diabetic drug which research has shown could have anti-ageing benefits. “I’m going to keep taking it. I’ll keep doing it as an experiment,” he says.

This appetite extends to his scientific interests. “As any academic will tell you, when you change subjects it’s really risky too. You have to learn a new language, and you have to get accepted by your peers and convince people to give you money without a track record,” Spector says. “But I like throwing myself in.”

When I ask if there is a moment when he recognises it’s time to move on, he pauses for the first time. “I find that when I’m reading the papers we’ve written, if I’m not very interested in the next step or the next stage any more — that’s when I’m going to look for something else.”

Spector has fed his compulsion for novelty through an unusual approach to studying epidemiology: a registry of 15,000 sets of identical twins in the UK that he has enrolled over the past 29 years. “You can’t mate humans in a lab so this is the next best thing,” he says. “The goal is to understand nature versus nurture.”

Spector’s team has published on the heritability of 200 diseases and disorders, everything from shortsightedness and cataracts to autism, back pain, arthritis and obesity. He has even studied the genetic origins of the twins’ political views, sense of humour and sexual orientation.

4.6m People in Britain who have logged on to the Covid Symptom Study app to report on their health since the start of the pandemic

His subjects have agreed to colonoscopies and skin and muscle biopsies, taken hair samples and collected their faeces in receptacles. During the pandemic, 14,000 twins have been filling little vials with blood samples and putting them in the post regularly, while also filling out questionnaires every three months about how the pandemic has affected their lives. “They feel an incredible loyalty to him,” says Spector’s colleague Hart. “We decided to get a life-size cardboard cut-out of him for when he travelled, and they would come to the clinic and get their pictures on either side of Cardboard Cutout Tim.”

His latest — and longest-lasting — obsession with diet and gut health came out of this remarkable data pool. It began when he was studying the genetics of obesity in twins. Some twin pairs differed in weight by 10 to 15kg, and he had been trying to figure out why.

“I had been looking for years to find the reasons that twins are different. To see radically different parts of their bodies is quite unusual,” he says. Two things struck him about these twin pairs: first, their gut microbes were very different. The other was diet. “It was then I started to say diet and gut health are probably the most important things to look at here.”

As a result, Spector published Spoon-Fed, a myth-buster of food fads such as calorie counting and vitamin supplements. He’s currently working on a related tome, a lexicon of food — everything you need to know to make the right choices about what to eat. Spector has himself experimented with dozens of diets. He went vegan but missed cheese too much, gave up meat, which he still avoids, fasted intermittently and ate an intensive unpasteurised French cheese diet.

He even spent three days as a hunter-gatherer with the Hadza tribe in Tanzania, eating a million-year-old diet of baobab porridge, Kongorobi berries, wild porcupine and hyrax (a squirrel-like relative of the elephant), which he said boosted his microbiome diversity like nothing else.

Spector’s current diet involves breakfast only on alternate days, including kefir and a “good black coffee”. For the remaining meals, he usually eats plant-based cuisine, and uses mail-order recipe boxes to teach himself to become a better vegetarian cook. “I have a fermented food every day, and am always making my own kombucha. It’s very visually pleasing,” he says. “And after 10 days you have a complex and interesting drink. It’s got more microbes than yoghurt.”

Zoe grew out of his obsession with diet. When coronavirus arrived in the UK, the team had been in the process of designing a service to send customers an at-home finger-prick and glucose-monitoring kit. Based on its analysis of how a user metabolises certain food groups, an accompanying app gives a personalised report on how their body may respond, including sensitivity to dietary inflammation.

Some people may experience a sugar crash after pasta, while others feel something ­similar after eating muffins. The same foods don’t fill everyone up in the same way. “[I’m] trying to fit in the whole idea of personalised nutrition. We need to be explorers of our own bodies more, and see what works for us, not believe in dogma,” ­Spector says. “I want people to educate themselves, and they can make choices helped by tech like with Zoe.”

Although the arrival of Covid-19 temporarily diverted Zoe’s business, Spector has, as a result of the dataset gathered over the past year, been able to bring his research back to nutrition. A study of app participants found that quality of diet is crucial for Covid-19 outcomes. Even adjusting for obesity and deprivation, researchers found that people eating a larger proportion of ultra-processed foods and fewer vegetables and fruits had higher levels of severe Covid-19. They are 20 per cent more likely to go to hospital.

20% Increased likelihood of needing hospital treatment among Covid-19 patients whose diets feature high levels of ultra-processed foods

“The link for me is the fact that gut microbes play this role in immunity and that’s been what is missing. The fact that the British are so unhealthy is in large proportion due to unhealthy diet, and the government is doing nothing about that,” Spector says. “You can see it in Covid, but also ­obesity, heart disease, diabetes, and it’s preventable. That’s why there is a 12-year difference in lifespan between those in Knightsbridge and those in Hammersmith.”

Spector’s strident views can occasionally be grating. “He is very, very honest and opinionated, sometimes too much,” his daughter Sophie says. “People who know him well, we know what he’s like. But there have been occasions that might rub up the wrong way with someone. He will never really hide what’s going on in his head.”

The UK government found this out to its cost in May 2020, when Spector began publicly criticising the glacial speed with which it was moving to track the virus. “It was extremely frustrating for the first three months. We had a lot of support from the Welsh and Scots governments [but] absolutely no support from NHSX [the health service’s innovation arm] or Public Health England or the English government,” he recalls. “Matt Hancock had set up NHSX as his personal toolkit and I think in retrospect he wasn’t keen on us succeeding because it would put NHSX in a bad light. We could have had a screening system up and running within weeks for the entire country, without needing tests if we had that co-operation from those people.” A friend of Hancock told the FT: “Matt was willing to listen to anyone who could help fight the pandemic. His whole approach is that fighting a pandemic is a team effort.”

Since then, Spector has managed to get £5m of funding from the Department of Health, but he wishes he could have done more. “Perhaps linking with people more politically astute than myself would have been helpful. My regret is that we had four million UK downloads but if we had got 20 million, we could have saved more lives.”

We need to be explorers of our own bodies more, and see what works for us, not believe in dogma

Spector is planning to use the latest tranche of money to expand the remit of his app, allowing people to log broader symptoms relating to their overall health. After surveying some of its users, Zoe found people wanted to use the app to monitor five of the most common adult illnesses: cancer, heart disease, arthritis, dementia and mental health. “No one else is collecting symptoms from a population in real time,” Spector says. “Reporting early symptoms could be incredibly valuable. These are all 10 times worse than before the pandemic, because they’ve been put off and not been helped in hospital.”

His dream, he tells me, is to make this the largest ever health study of its kind. The app would be more than a useful research tool to study chronic disease; it could also be a way to give back to users. If people continue logging their data at current levels, Spector’s app could list clusters of early symptoms shown by other groups of users, such as those recently diagnosed with breast cancer or dementia. The app would not attempt to diagnose patients, but to build up a large enough dataset over time to be able to spot early signs for various conditions and share that with users — something, Spector argues, the NHS should be doing as part of its prediction and prevention strategy.

Spector says he’s “not an expert” but doubts that the NHS in its current state is fit for the modern age. The system of having general practitioners as gatekeepers to specialist care is “failing badly”, he claims. “It’s already overloaded. We have the worst cancer survival rates in western Europe. It’s not acceptable. You need to cut out all these blockers of getting care, which is generally primary care. They aren’t doing it knowingly, but that’s the result of the system.”

In his view, an app backed by high-enough usage and a sufficiently large dataset could replace the UK’s current GP system, using the holistic picture of a person’s health built up over several months of data-logging, rather than the “eight minutes that a GP gets when someone is already ill”. Meanwhile, GPs could retrain to have two or three sub-specialties, rather than the dozens they currently need to triage every patient who comes into their examination room.

“With an app, you can get really accurate lifestyle data that you couldn’t get before,” Spector argues. “You know how people are eating, how they are sleeping, how much exercise they’re taking. On a fine-grained level, that allows us to work out impact on health and allows us to intervene.”

He continues, speaking passionately about the need for medical research to go entirely digital, about the future of healthcare in Britain and globally. One big idea after the next. It might all sound a little pie in the sky, if it weren’t Tim Spector talking.

Madhumita Murgia is the FT’s European technology correspondent

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