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Prof François Balloux is director of the University College London Genetics Institute. His work focuses on the reconstruction of disease outbreaks and epidemics. Together with his colleague Dr Lucy van Dorp, he led the first large-scale Sars-CoV2 genome sequencing project. During the pandemic, he became a leading scientist on Twitter, where he describes himself as a “militant corona centrist”.
Would you say that a worrying new variant is still the main threat to our exit from this pandemic?
We haven’t had one for a while. The four worrisome variants all emerged in the second half of 2020, and it’s important to keep in mind that viruses are evolving at a fairly regular rate all the time.
However, with Alpha, something unexpected happened: there was a sudden build-up of mutations. A reasonable assumption is that Alpha emerged from an infection of an immunocompromised person or an infected person for a very long time. The three other worrisome variants (Beta, Gamma, Delta) emerged through gradual accumulation of mutations.
So it’s not always predictable?
It’s extraordinarily difficult to predict a shock like the Alpha variant. What is easy to predict is that mutations will continue to appear and the virus will gradually drift away as vaccines become less effective over time.
There was a suggestion in a sage paper that a very deadly variant could emerge, while other scientists suggest that the virus has reached its “maximum adjustment”, that if it evolves further it will lose the ability to coexist with its human hosts.
It is important to balance the fear of predictions with their reasonableness. The probability of the emergence of a 50 times more deadly line is extraordinarily implausible. I say this because we have 200 respiratory viruses circulating and most of us are infected regularly. We have never seen this kind of sudden change in mortality. I’m not saying it’s impossible, but you might have a better chance of winning the lottery jackpot multiple times.
Where is the emergence of the alpha and delta variants on your jackpot winning metric?
This is such a difficult question. It’s a bit like asking what the odds are of someone winning the jackpot, without having a clue how many numbers there are on the lottery ticket.
The Alpha and Delta variants emerged, and they were obviously winning combinations of mutations for the virus – although we also know that no other comparable transmissible viral line has emerged so far, despite millions of infections and a constant influx of mutations.
Another concern, a mutation that allows the virus to “escape” vaccines …
Over two million viral samples have been sequenced, and we’ve probably seen all of the technically possible mutations already. From our observations, we know that vaccine breakout will not occur after one or two mutations – it will require a build-up resulting in the right combination. We will not go from one day everyone protected to everyone vulnerable the next day. We will have time to update the vaccines.
In addition, while a vaccine variant would indeed be able to infect vaccinated people much more easily, it would not negate the protection against serious illness and death offered by the vaccine and previous infection.
Where are you on adolescent vaccination?
It is the mother of all questions. There are people who are very passionate on both sides. Given the data available – and few adolescents have been immunized – I think the JCVI was probably right to err on the side of caution in recommending the vaccine for healthy over 18s first, and as time goes on. that more and more data are available, for the healthiest. -16s. There is a problem with heart inflammation in young men who have been given mRNA vaccines. One possible solution might be to give adolescents a single dose – most side effects were seen after the second dose. However, a single dose regimen has yet to be tested or approved.
You said that a “not insignificant” number of long-Covid the cases are psychosomatic.
We know that infections such as Covid lead to post-viral syndromes. At the risk of being unresponsive, I would be surprised if there was no connection between the severity of the disease and the severity of the follow-up symptoms. Like tuberculosis or the flu, people with a severe case should expect to take a long time to fully recover. And sometimes the recovery is never complete.
The situation is more complicated with a mild infection. Post-viral symptoms can occur but it seems relatively implausible to me that this happens very frequently. In all likelihood, some cases are psychosomatic – although this does not make the suffering less real for those affected or reduce the cost to society. All disease is real, whatever its cause.
There is a mental component to health and illness. The simple fear that something bad is happening to us can make us feel bad. A remarkable example of this process can be seen in the way that over 30% of people who were recruited into the control arm of the Pfizer vaccine trial reported headaches and fatigue, although they did not. have not received a vaccine injection.
You had a bad Covid crisis – does this inform your point of view?
I try to ignore my own experience when thinking about public health issues. Having said that, I would probably be included as having a long Covid because six months later I haven’t fully recovered my sense of smell or taste. I think we need a meaningful definition that indicates whether you’ve returned to full physical shape. I want to stress: If you have a serious infection, you don’t necessarily expect to be fine again in three months.
Your Twitter bio indicates that you are a “centrist corona activist ”. Whyou mean ?
From the start, the pandemic has polarized. Some thought you had to “let it rip” or “take it on the chin” and others thought it was necessary to fight to eliminate it everywhere. These camps fought for 16 months and it’s pretty toxic. Both are quite extreme and unrealistic. I have always believed that very careful mitigation could keep the pandemic under control until the vaccines arrive. A few countries have come together, such as Singapore, Norway and Denmark.
The scientist is supposed to revise his conclusions as the evidence evolves. Do you think scientists on both sides of the debate retained their views despite the evidence?
It’s selfish to say “they don’t change their minds, I do” – despite the fact that I didn’t. Our brains work in a Bayesian way – we have priorities that influence how we view new information. As a scientist, it’s very important not to have an extremely strong track record – you need to be open to surprise and let your assumptions be updated with new data. It is important to engage with new evidence. Being dogmatic is problematic.
This problem is amplified when, as now, scientists speak directly to the public …
Before the pandemic, we rarely asked scientists anything, or we were listened to in a polite, somewhat bored manner. But now people are clinging to the words of scientists, which can make it harder for them to change their mind. Few scientists have changed their take on Covid, but when they do, it is often not well received – there is an element of group thinking and for more media savvy scientists, an expectation from their crowd. adoring that they’re not supposed to.
Neil Ferguson has been criticized for his predictions of 100,000 cases one day after the restrictions were relaxed on July 19.
I know Neil, he was my boss for five years. His predictions were quite pessimistic but he tends to be pessimistic – which is not a criticism. If you are in a position of authority to advise the government, you really want to err on the side of caution.
Can you explain what you mean by “scientific populism”?
As the pandemic progressed, the mood of the public grew darker and more fearful, which created a market for gloom and unhappiness. It’s as bad as the effects of super optimism at first – stay home for two weeks, it’s mild illness or wear a mask and you’ll be gone. So I kind of captured the market for corona centrism – not to be systematically optimistic or pessimistic and to clarify that there are major uncertainties. And that gives power, because understanding things is.
You have often said that the pandemic will be over by mid until the end of 2021. Do you agree?
It depends on how you quantify it. I would say the pandemic is over when Covid-19 does not cause much more death than other respiratory viruses in circulation. This will happen first in places like the UK which have had the privilege of getting immunization coverage – I anticipate early next year at the latest.
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