Week after week, reports published by the microbiology department of the National Health Laboratory (LNS) have confirmed that variants are taking precedence in Luxembourg (as elsewhere in Europe) over the original strain of Sars-CoV-2, the virus which causes covid-19. Variant strains which have one thing in common: they are more infectious than the original one. It could have therefore been expected in the grand duchy to have an explosion of infections, but this did not happen.

The latest weekly statement sent by the government last Wednesday instead showed a declining incidence rate for the week from 1-7 March, from 210 to 191 new cases per 100,000 population.

Nevertheless, the so-called British variant has settled in. As of 28 February, the date of the last data analysis published last week, it represented 65% of new cases of infection--therefore, the large majority, ahead of the so-called South African variant (responsible for 16% of new cases).

However, a study published on in the British Medical Journal on 10 March suggests that the British strain is 64% more deadly than the original Chinese strain. "This could explain a certain mortality among us in recent weeks ..." conceded Dr Thomas Dentzer of the health directorate last week, referring to the study in a Paperjam interview.

A study of 110,000 people

The study in question, carried out by researchers at the universities of Exeter and Bristol, is based on data collected from nearly 110,000 people who were diagnosed positive between 1 October 2020 and 29 January 2021 and who were not hospitalised. These individuals were followed for 28 days. Half of the patients were infected with the original strain of Sars-CoV-2, the other half with the English variant. The researchers then compared the death rates in these two groups, taking into account factors such as age, gender and ethnicity.

They found a much higher number of deaths (227) in people infected with the “British” variant compared to the ancestral strain (141), which represents an increase in mortality of 64%.

"These are figures, for now”

“This is a statistical study, reporting a correlation which is a good clue. But these are just figures, for now..." explained Dr Danielle Perez-Bercoff, virologist and researcher at the Luxembourg Institute of Health (LIH), earlier this week.

“What I mean is that we would have to dig into why there would be this increase in mortality with this strain. Is it just because the infection is higher at the population level (more people infected), or does the virus more easily infect cells in the body and therefore cause more damage to the organs and blood vessels? Among the mutations of this variant (there are 17 of them), are there some that give it a more pathogenic power? As of yet, we don't know. And this study does not help us at that level, it just makes us more alert…”

This article was originally published in French on Paperjam.lu and has been translated and edited for Delano.