Why the delta variant threatens efforts against covid-19

Why the delta variant threatens efforts against covid-19
Why the delta variant threatens efforts against covid-19

The delta variant of covid-19, which engulfed the UK, has become dominant in Portugal and has appeared in various outbreaks in Germany, France and Spain, prompting European health officials to call for further action to slow its spread.

The variant, which first emerged in India, currently represents only a fraction of the total cases of covid-19 in continental Europe, but is gaining ground, according to an analysis of global genomic data from the tracking database. of the Gisaid virus.

This variant accounts for 96 percent of covid-19 infections sequenced in Portugal, more than 20 percent in Italy and about 16 percent in Belgium, according to Financial Times calculations. The small but growing number of cases has raised concerns that the delta variant may undermine the progress made by the EU over the past two months, and that they have brought new infections and deaths to their lowest level since at least last fall. “We are in the process of crushing the virus and the pandemic, and we absolutely must not allow the delta variant to take over,” French health minister Olivier Véran told journalists at a Paris vaccination center on 22 June.

Véran said that 2 to 4 per cent of the virus samples analyzed in France were found to be of the delta variant: “That might still seem like a low percentage, but it is similar to the situation in the UK a few weeks ago.” The Financial Times’ analysis of Gisaid’s data suggests that this percentage may be higher.

In Portugal, transmission of the variant has been detected in the population of the Lisbon metropolitan area, where more than 60 percent of new covid-19 cases have been identified in the country. Non-essential travel to and from the city was banned from June 18-20 in an effort to prevent the spike in cases from spreading to the rest of the country.

Scientists across the continent are now looking to the UK – where covid-19 cases have tripled in the past month and the delta variant accounts for around 98 per cent of all new infections – for clues as to what might be happening. in the future and what measures may be needed. After official data showed that the delta variant appears to increase the risk of hospital admission by 2.2 times compared to the alpha variant, the UK government postponed the end of the remaining restrictions against covid-19 by one month. “The decisions the UK makes to reopen everyday life and society will serve as a laboratory for us in Europe,” said Bruno Lina, a Lyon virologist and consultant to the French government who is committed to coordinating variant sequencing in the country.

Whether the various delta outbreaks in the EU will turn into major epidemics will depend in part on how many people have been fully vaccinated, the scientists said, and on people’s behavior now that many restrictions on daily activities have been lifted. and working. Recent research by the UK government has highlighted the need to complete vaccination programs as quickly as possible.

How much vaccines protect
According to data collected by Public Health England, the first dose of a covid-19 vaccine is generally less effective against the delta variant than the others. Two doses increase protection against symptomatic delta variant infection from 33 to 81 percent. While around 46 per cent of the population in the UK has been fully immunized, vaccination rates in most continental European countries are between 20 and 30 per cent. In France, around 26 per cent of the population has been fully vaccinated. The French authorities are currently trying to contain an epidemic in the Landes region, near the border with Spain, where 125 cases of the delta variant have been confirmed by genetic sequencing and another 130 are suspected to be attributable to the same variant, amounting to about 30 percent of recent infections in the area.

Some outbreaks of the delta variant have also been identified in recent weeks in the southern suburbs of Paris and in an art school in Strasbourg. In each of these cases, health authorities responded with the same formula: greater contact tracing and a renewed push to vaccinate people in affected areas. “If we keep vaccinating at a good pace, and stick to some non-drug measures like wearing face masks at home, we can still limit the circulation of the virus this summer,” said French virologist Lina. “This variant will replace the others – we must be aware of it – but it does not mean that it will lead to a new epidemic wave”.

Scientists fear that the delta variant may have already spread further but not been identified, given that in continental Europe the genetic sequencing work needed to identify the variants is a bit slow. The UK has sequenced more than five hundred thousand sars-cov-2 genomes, while Germany, France and Spain have sequenced around 130,000, 47,000 and 34,000 respectively. “It’s a costly, time-consuming and neglected operation,” said Antoine Flahault, director of the University of Geneva’s Institute of Global Health.

Differences in diffusion
Yet Denmark, which has sequenced a high percentage of cases, has nevertheless identified only a small number of delta-type infections, even though the arrival of the variant in the country occurred almost simultaneously with the United Kingdom. This could be partially explained, the experts said, by the demographic and movement differences, including the number of cases imported into the UK from regions with a high prevalence, such as India, and the living conditions in the communities where spreads.

The difference in the rate of diffusion of the delta variant in European countries remains “a bit of a mystery,” said Jeff Barrett, director of the Covid-19 genomics initiative at Cambridge’s Wellcome Sanger institute. However, many experts believe that the delta variant will become dominant wherever it spreads. The key, they say, will be to increase the percentage of fully vaccinated people by slowing transmission of the virus as much as possible. “We have to make sure that the message remains very clear,” said Lina from Lyon. “It’s not over here”.

(Translation by Federico Ferrone)

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delta variant threatens efforts covid19

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