Removing Covid PCR Testing For UK Arrivals Will Put Us Dangerously At Risk Of New Variants
Grant Shapps, the secretary of transportation, announced changes to the rules on international travel. In addition to the simplification of the ‘traffic light’ system – the Amber List is removed and eight countries will be removed from the Red List – fully vaccinated people returning to the UK from a low risk country will no longer have to pass through a screen PCR test for Covid. Arrivals from Red List destinations will still need to be quarantined in a government approved hotel.
Consider the possible implications of this.
Vaccination has been the main success of this pandemic, with over 100,000 lives saved in the UK to date. However, while vaccinations are incredibly effective at preventing serious illnesses, only about three in four infections are prevented. Doubly vaccinated arrivals may produce slightly lower viral loads and infections may be of shorter duration, but it is entirely possible that they could still carry the virus with them.
In an attempt to avoid this, arrivals to the UK will instead need to undergo a supervised lateral flow test. While they are very good at detecting the virus when a person is infectious and has a high viral load – and detect about three-quarters of infections that can be identified by PCR – they can miss low levels of infection. When a person is first infected with Covid, their viral load will initially be low and then increase over the next few days. When people travel to international travel centers, they are in places with a high risk of getting infections, but if they are infected within about a day of their lateral flow test, it may not be. not be detected.
With high case rates in the UK, you might think another case doesn’t matter – until we look at importing new variants. PCR tests are used to determine the genetic sequence of imported viruses. We witnessed the importance of being able to understand which variants are imported into the UK when the Delta variant appeared. Leading sequencing efforts led by UK scientists have facilitated real-time tracking of Delta, allowing us to detect outbreaks and implement surge testing in parts of the country, including Bolton, and impose local restrictions in an attempt to delay the spread. The identification of viruses imported by PCR is of obvious public health interest.
Travel centers bring together people from different geographic locations, serving as a mix for the exchange of virus variants. International travel coupled with the extreme contagiousness of the Delta variant has ensured its current global dominance. However, it is quite possible that a new variant emerges, better able to escape the immunity provided by vaccinations. If that happens, we will have to react very quickly to minimize the threat posed by such a variant. Sequencing imported viruses via PCR tests gives us the best chance of doing this – so it is imperative that all positive lateral flow tests be followed by one.
Conversely, the elimination of PCR tests could increase the use of the vaccine. In France, where vaccinations were mandatory to access the hotel industry and certain public events, attendance has increased. The difference in cost – PCR tests cost travelers between £ 60 and £ 200 – may also encourage people who wish to travel but have reservations about vaccination to take the plunge, so to speak.
At present, the number of cases is high and is expected to increase due to the return of students to educational institutions. The NHS is under immense pressure as the military has recently been called in to help with emergency responses in Scotland. Outbreaks of other respiratory viruses are also expected. As we head into winter with these worsened issues, abandoning one of our primary surveillance strategies is now inappropriate. We all look forward to a future where such measures are no longer necessary, but we are not ready yet.
Dr Eleanor Gaunt is a research fellow at the Roslin Institute at the University of Edinburgh. She did her PhD on clinical correlates and epidemiology of respiratory viruses and is now studying the molecular biology of influenza A virus and SARS-CoV-2
This article has been updated to reflect the government’s announcement