International travel should reopen slowly, with any traffic-light system having the potential to be “leaky” to Covid variants, a senior scientist has said.
Professor Robin Shattock, head of mucosal infection and immunity at Imperial College London’s department of medicine, said an ideal scenario would be for people to quarantine when they return from any country – though this was unlikely to be seen as a practical option.
In a wide-ranging interview, he said it was possible coronavirus will become “much more of a fairly trivial infection” for most people while it was still uncertain whether the entire population would need to be vaccinated again each winter.
The travel taskforce set up by Boris Johnson is due to report shortly, with many expecting it to propose a traffic-light approach.
This ranks countries red, amber or green depending on infection rates and the prevalence of Covid-19 variants in overseas destinations.
In an interview with the PA news agency, Prof Shattock said: “I suspect there will be pressure to start international travel again, probably still with self-isolation/quarantining when you come back to the UK.
“There may be some implementation of a scheme where if you’ve had the vaccine you’re allowed to travel.
“I don’t know that it will necessarily be mandated by governments, but it may well be mandated by different carriers.
“Or you may find that different governments around the world put in place requirements so it may not be that the UK says you can’t travel without a vaccine, but if you’re going to a holiday destination they might say, ‘well we’re opening it up to people who have been vaccinated’.
“It’s a very fluid picture. I’m sure that, over time, we will start to return to international travel.
“I think it’s going to be slow, I think it’s going to be cautious and I don’t think it’s likely to take off in a big way until at least the autumn when everybody has had hopefully one, if not two, doses of a vaccine.”
Prof Shattock said the traffic-light system is “one approach but it’s going to be leaky”, owing to the risk of importing variants of concern that may affect vaccines.
“There are always possibilities of getting around that type of system. It might be a way of starting to release some travel, but it will need to be monitored very carefully.”
He said the ideal scenario would be people quarantining when they fly in from any country.
“I think that would be the ideal scenario but whether that’s practical and whether people will accept that … because it requires the legislation to say ‘that’s what you’ve got to do’. But people have to adhere to it, otherwise it’s ineffective.”
However, he said border controls “do definitely make a difference”, adding: “If you completely opened up travel tomorrow and everyone could come in and out of the country, we’d be in a much worse situation.
“So, with everything it’s a fine balance. If you were purely being risk averse, you would keep everything very, very restricted. But that’s not necessarily acceptable or practical.”
On how coronavirus may evolve, Prof Shattock believes it is possible that it could eventually become “much more of a fairly trivial infection” for the majority of the population.
“Then it’s more about continuing to protect the vulnerable, but it’s not going to be such a large issue, ” he said.
“The variants are still a big question. But what is perhaps reassuring to some extent is we’re not seeing variants going off in all sorts of different directions.
“What we’re seeing with this current coronavirus is it’s popping up with the same mutations in different parts of the world so it seems to be converging, rather than diverging.
“As most viruses evolve, they tend to evolve to be transmitted more easily, but less pathogenic, so less likely to cause severe disease.
“So there are two possibilities – it could become less of a threat over time or it could be that there will be new variants that we need to catch up with and boost (with vaccines) in the future.
“We just have to see how it unfolds, but it’s definitely not a certainty that the whole population will need to be vaccinated year on year.
“I suspect that that’s less likely in coming years, although I think it’s likely that the elderly will need an annual vaccination.”
Prof Shattock is currently working on variants using self-amplifying RNA vaccine technology, which uses lower doses of RNA.
His technology means vaccines can be adapted in just a few weeks to take account of any variants, though Prof Shattock is keeping watch over what may happen with future pandemics.
“The technology can be very readily adapted for any variant that might come our way … but we very much have an eye on something completely new (that) may come out and we need to be prepared for every eventuality.”
On the risk of future pandemics, he said: “Certainly we recognise scientifically that this kind of effect is happening more frequently.
“Covid has been a big wake-up call to the world but in some ways making a vaccine against Covid-19 hasn’t been as challenging as people predicted it might be, which is a good thing.
“If something comes along that’s a harder challenge, what we call pandemic X, a completely unknown virus – we know a lot about coronaviruses – but something that we’ve never seen and there’s no scientific experience, that would be a much bigger threat and challenge to humanity.”
As for Covid, there is the possibility of combining the flu vaccine with one against the virus, though “it will take some time to put that together”, he said.
For now, he thinks the UK is prepared to give booster vaccines this autumn to deal with variants of concern, such as those originally identified in South Africa and Brazil.
“The unknowns are whether variants will be able to circulate once everybody is vaccinated,” he said. “We really don’t know whether that’s going to be a very small problem or a very major problem.
“Having a variant booster ready to go makes sense.
“The other thing we just have no idea about is the duration of protection that these vaccines will have – is it 12 months, is it 24 months? We’re collecting those data in real time.
“If the protection is short-term, we need to have vaccines ready at least this winter to boost.
“Now, it may be that we get them ready and they’re not necessarily needed.”
He said it was not yet known whether the entire population would needed to be vaccinated again, or whether doses would just be needed for the elderly and most vulnerable.
“I think right now we don’t know,” he said. “The reason we don’t know is some of these variants may not be protected against as well on an antibody-based level, but we would also have T cell immunity, which is much broader and the variants are less likely to get round that.
“One of the possibilities is that that back-up, that T cell immunity, might actually prevent you being seriously unwell and ending up in hospital.
“If that does, then you may not need to vaccinate the entire population, but it’s one of those difficult decisions because we won’t know whether it’s a problem until it’s a problem.”
Prof Shattock said more data was needed on how well existing vaccines work against variants but “the real issue right now is that we just need to get everybody vaccinated so that variants don’t become a problem”.
He added: “I think if we get everybody vaccinated, it’s going to be less of a worrying scenario.
“The real difficulty would be if we suddenly say, ‘oh, everything’s fine’ and we see the variants taking off in a big way.
“So we’re in a period right now where we need to get things done in order for the variants story not to be a major issue.”