In a letter published in the British Medical Journal (BMJ), virologists Jangu Banatvala and Deenan Pillay have called for more “caution” as the UK prepares to reopen its borders to international travel.
Under the new system, countries have been divided into three categories – red, amber and green – depending partly on their national infection rates alongside the success of their vaccine rollout.
From 17 May, people in England and Scotland can take holidays abroad in the green countries, which includes Portugal, Israel, Singapore and Iceland, without having to quarantine when they return. However, not all of these nations are currently accepting foreign visitors.
But both Prof Banatvala and Prof Pillay, along with Peter Muir, a consultant clinical scientist at Public Health England, argue that plans for foreign travel and summer holidays need to be reconsidered.
“Until our vaccination programme is complete, and while there are significant risks of immune-escape variants arising in countries with high transmission, it would be remiss to abandon all attempts to limit new variants being imported into the UK,” they write.
Variants originally detected in South Africa, Brazil and India have all been found in Britain. In Bolton, a recent uptick in cases across the town has been attributed to the India variant, which is thought to be highly transmissible. Experts also believe that it is circulating on a community level in parts of London.
“As local indigenous transmission decreases [in the UK], such imported infections will become the main source of new infections, and border controls will become increasingly important in limiting this risk,” the experts add.
They point out that the Lancet Covid-19 Commission Task Force identified risk of spread through air travel as a priority and emphasised that the entire door-to-door travel process should be evaluated to minimise the risk of transmission.
The All-Party Parliamentary Group (APPG) on coronavirus has meanwhile identified long queues at airports, failure to separate arrivals from red and amber countries, and fake Covid-19 test certificates as significant risks to biosecurity, the experts write.
“In the UK, border controls are porous,” they say. “This reflects the political unwillingness to impose stringent controls from early in the pandemic, as well as the inadequate public health measures which have been put in place.”
They also highlight the example of Chile, which, despite its successful vaccination programme, suffered a rise in cases after relaxing social distancing and travel restrictions.
“Public health experts say that this, combined with more infectious variants, has contributed to the surge in infections,” the BMJ letter reads.
And the authors warn that the aviation industry's current enthusiasm to resume international air travel and overseas holidays needs to be checked, saying "it flies in the face of the twin needs to control international virus transmission, and tackle the climate emergency and environmental degradation”.
“We must consider the urgent and serious global public health threat of climate change,” they add. “We should reduce the amount of air travel not only because of Covid-19, but also because of the detrimental impact that this has on our climate."
A Government spokesperson said: “The traffic light system cautiously balances the reopening of international travel with managing the risk of imported variants. This list is regularly reviewed using the most up-to-date, robust data to ensure we keep the general public safe.”