French scientists wary about preparedness for coronavirus variant

French public officials say laboratories have detected only a handful of cases of the potentially more contagious coronavirus variant, but scientists warn time is of the essence if the country wants to anticipate a spike in cases of the sort that has led to a tough new lockdown in Britain.

Can France avoid a lockdown of the kind declared in Britain, which has imposed its most restrictive measures since last spring due to widespread cases of an apparently more virulent strain of the new coronavirus?

Officials said Tuesday there were only a handful of cases in France and that they were carefully monitoring the new variant.

French scientists though have warned about the variant in Le Monde newspaper, whose Wednesday edition ran a headline saying the country was in a race against time.

“It will be very difficult to block its spread and it's crucial to protect the most vulnerable people as quickly as possible, starting with those over the age of 75,” epidemiologist Arnaud Fontanet told Le Monde.  

“We have to hope for inertia when it comes to the spread of this clone in France,” said Fontanet, a Pasteur Institute epidemiologist and member of a panel advising the government on the epidemic. adding France “will not have the three months that England had: we have to go faster.”

Low intensity early spread

The new variant was identified in England for the first time in September of last year and spread at low intensity until becoming dominant in several regions in December. At that time, Public Health England designated the variant VoC 202012/01, for Variant of Concern.

The British government rang alarm bells on 19 December on the wide reach of the potentially more virulent strain of the new coronavirus, prompting dozens of countries to impose travel restrictions from the UK.

France's restrictions disrupted one of Europe's busiest trade routes for several days before Paris and London agreed on testing rules, and France now says travellers from the UK are closely monitored.

But VoC 202012/01 is already present in France, with a first case detected on 21 December in a French person who had travelled from London to the city of Tours.

A work-around for tracking the variant

Le Monde reports that while France does not have the same genome sequencing capacity for tracking viral strains as Britain, scientists at the national research centre in Lyon have found some variants respond abnormally to the classic PCR nasal cotton-swab tests in widespread use for detecting Covid-19.

For some variants, the tests do not picking up two amino acids from the protein spikes the virus uses to infect cells. The researchers found VoC 202012/01 exhibits this spike deletion and called on laboratories to forward results of tests that showed the anomaly and who came from the UK.

This method was used to identify the first French case of the variant in Tours, and researchers in Lyon and Paris say they have been inundated with enough samples to start tracking VoC 202012/01.

“It is still a bit early to have a clear idea of the spread of this variant,” Sylvie van Der Werf, head of a research group at the Pasteur Institute in Paris told the newspaper, adding the centre was looking to set up a nationwide sampling system.

“The goal is to assess the evolution of the variant compared with all others to discern trends,” she said. For example, a spike in cases whose tests display the anomaly might signal a spike in infection by the VoC 202012/01 variant.

“Its spread is surely limited on [French] territory, but a cartography has to be established as soon as possible,” Fontanet remarked.

"There is a real sense of urgency in tracking this variant on our territory," Fontanet told French television on Monday, adding that there were probably around a dozen examples detected so far.

Predicting virulence

A VoC 202012/01 map would help scientists elaborate different scenarios as research also unpacks the variant's properties, namely how it affects the R number that indicates how many people would be expected to be infected by someone who tests positive.

In France, the R number fell to 0.7 to 0.8 during the second confinement in November, below the threshold of 1 beyond which, in theory, disease will eventually reach epidemic proportions.

British Prime Minister Boris Johnson said in December the new variant was 70 percent more contagious than average, while UK researchers estimate the difference to range from 50 to 70 percent. Even 50 percent would mean an R number 1.5 times larger, and therefore superior to 1 even under current conditions in France, Le Monde notes.

“This variant does not change the strategies and tools in our arsenal, but makes them a bit less effective,” epidemiologist Pascal Crépey of the EHESP School of Public Health told the paper.

“From an epidemiological point of view, a nationwide confinement makes sense to avoid restarting the epidemic, but we can see that it's complicated to push for this strategy when, in most departments, the epidemic is under control. The population is starting to be wary.”