Coronavirus: What do we Know about the Colombian Variant, Which Killed Seven People in a Belgian Nursing Home?

General News
The variant that appeared in Colombia has infected several residents of a nursing home in Zaventem.

EPIDEMIC: This new variant first identified in Colombia claimed the lives of seven residents of a nursing home in Zaventem, Belgium.

  • Appeared in Colombia, the B.1.621 strain of the coronavirus claimed the lives of seven residents of a Belgian nursing home.
  • However, all had a complete vaccination schedule.
  • But this new variant carries the E484K mutation, associated with a risk of immune escape.

And one more variant. While France is currently undergoing an epidemic wave due to the Delta variant, the list of strains in circulation is growing with a newcomer, the Colombian variant, or “strain B.1.621”. Seven residents of a nursing home in Zaventem, near Brussels in Belgium, succumbed to this variant, even though they all had a complete vaccination schedule. A total of twenty-one residents and seven staff members were infected with this variant within the Ter Burg residence, reports RTBF. According to the Flemish Health Care Agency, it is a visitor who is at the origin of the source of contamination. “The person in question was asymptomatic. She had visited the nursing home a few days before taking a positive test, ”Ria Vandenreyt, spokesperson for the health agency, told the Belgian press.

The variant was placed under “enhanced surveillance” in May by the World Health Organization (WHO), which is monitoring its worldwide distribution. So, should we expect a spread of this strain? If it does not seem more virulent than the previous strains, the mutations it carries could on the other hand cause an immune escape.

Where does the Colombian variant circulate?

As his nickname suggests, he was first identified in Colombia in January 2021, according to data collected by the WHO . It first spread to the north of the country before moving up the American continent, causing contamination in Mexico and the United States, before crossing the Atlantic. To date, around thirty countries have identified this variant in samples, including Great Britain, Germany, Spain, Portugal and Italy. He was also spotted in France as early as April. But its presence is however very rare, and its “level of circulation remains overall very low”, reassures Public Health France.

Thus, according to data collected by Sante publicique France and the international virological database Gisaid (Global Initiative on Sharing Avian Influenza Data), as of July 27, 53 cases have been confirmed in France, including 21 in Île-de-France. 

Is it more transmissible than previous strains of the virus?

In Colombia, where the B.1.621 strain appeared, “it does not seem to be in the majority, and represents approximately 35% of the sequences deposited with a collection date equal to or after May 1st, 2021”, we learn in the latest risk analysis linked to emerging variants carried out by  Sante Publique France and the National Reference Center (CNR) for respiratory infection viruses at the Institut Pasteur.

“To date, there is no evidence that [the B.1.621 strain] competes with the Delta variant and it seems unlikely that it is more transmissible”, considers the health agency Public Health England , while only thirty-two contaminations by this variant have been identified in England in recent weeks. For the moment, across the Channel, like almost everywhere in the world, it is the Delta variant which dominates. In France, “according to GISAID, the VOC [ variant of concern , or variant of concern] Delta represented 97% of the sequences carrying the L452R mutation over the period from July 1 to 27,” observes Public Health France.

The Colombian variant has been classified as a “  variant of interest  ” by the European Center for Disease Prevention and Control, but not by the WHO, which for the moment is monitoring it closely, without deeming it worrying. This explains why it was not renamed by a letter of the Greek alphabet. It is “probably less transmissible than the Delta, which would mean that it would have little chance of supplanting it,” said Rémi Salomon, president of the APHP establishment medical commission.

Is this variant more virulent or resistant to vaccines?

The B.1.621 lineage “carries the three mutations of interest E484K, N501Y and P681H”, indicates Public Health France. However, E484K , which is also found in the Beta variant which appeared in South Africa, is associated with a risk of immune escape. This new variant could therefore “show similar immune escape properties”, advances Public Health England in a report on the risk assessment of this strain, published on August 6. “B.1.621 [is] a variant which could be more resistant to natural or vaccine immunity,” abounds Rémi Salomon on Twitter.

In practice, a person immunised by contamination by the coronavirus or by a complete vaccination schedule would be more likely to be infected with this variant if they were exposed to it. That is precisely what happened in the Zaventem retirement home. But “the very advanced age of the patients also played a role,” said virologist Marc Van Ranst to the Belgian press, the victims being between 80 and 93 years old.

To date, around twenty outbreaks of contamination by this new variant have been identified in Belgium.

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