“A new wave in Europe at the beginning of summer”?

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South Africa is currently experiencing a new wave of Covid-19 infections. Two new sub-variants of Omicron, BA.4 and BA.5, are the cause, and “they appear to be more transmissible” than those currently known, explains epidemiologist Antoine Flaholt. maintenance.

South Africa is once again the center of scientific attention on Covid-19. Last November, Omicron was first discovered there before it spread around the world. This time, it’s two new sub-strains of this same species that are causing the start of a new pandemic wave in South Africa, according to the warning issued at the end of April by the Center for Epidemic Innovation and Response.

On Wednesday 4 May, the Director-General of the World Health Organization, Tedros Adhanom Ghebreyesus, said.

At the same time, health indicators in Europe and France are improving: according to figures from Public Health France, 47,925 people tested positive on Wednesday (-29.2% within one week), 6,767 people were hospitalized and 723 people were hospitalized in critical care. The course of seven days. (-24% and -24.1% within one week), or 693 people died within seven days (-15.7% within one week).

The national public health agency also specifies, in its latest weekly update, that 99% of the tests carried out in France are the result of the Omicron BA.2 sub variant – which has dominated others for weeks. But, the novelty, one BA.4 case and two cases of BA.5 were identified at the end of April in France. Since these sub-variables “appear to be more transmissible than their predecessors”, according to epidemiologist Antoine Flaholt, the risk of Europe facing a new pandemic wave “at the beginning of summer” exists.

France 24 : Why is South Africa experiencing a new epidemic wave ?

Antoine Flaholt: South Africa is seeing the emergence of two new subtypes of Omicron BA.4 and BA.5 that appear to be more transmissible than its predecessors. These cause a new wave of pollution, but we do not know the expected magnitude, nor the effect on the serious forms (hospitalization and mortality, ND). So far, the South African authorities have not seen a significant increase in the severity of these new variants.

What is currently known about the new BA.4 and BA.5 sub variants ?

Omicron’s sub-variables are developing at a hitherto unprecedented speed. There are several elements that require special attention from the international scientific community: BA.2.12.1 – which is actively circulating in the United States – and the BA.4 and BA.5 sub-variables that are still not well understood.

Typically, these sub-variables are spread to young, active and mobile segments of the community and thus do not reach those who are expected to arrive at the hospital. It is therefore difficult to accurately assess the virulence of these new subvariants at this point, ie the percentage of dangerous forms that cause them. We know it’s more portable (than other variants, editor’s note) because it’s a necessity respectively in the United States and South Africa.

At the viral level, two mutations affecting the BA.4 and BA.5 sub variants indicate increased susceptibility to transmissibility and immune escape. All this is similar to the emergence conditions we experienced with BA.1 and BA.2 (prevalent in recent months in Europe, editor’s note).

BA.4 and BA.5 – Many cases detected in Europe – could they replace the current dominant sub-variables in the medium term? ?

If it is too early to make predictions even after a few weeks, we can go back to the history of the prevalence of BA.1 and BA.2: they were also initially identified in South Africa, and there was only a month and a half between the peak of the Omicron wave in South Africa (15) December) and those observed in France (end of January for wave BA.1).

So we can believe that if BA.4 and BA.5 spread in Europe and follow the same path as its predecessors, a new wave may appear in Western Europe between mid-June and the beginning of summer. I insist that this wave of pollution will not necessarily be associated with a significant increase in hospitalizations and deaths, but that we must follow the current development in South Africa closely and prepare.

What does this situation say about the development of the Covid-19 epidemic in the world?

From the start, this pandemic was unexpected. At the end of nearly every wave, politicians and many experts predict the end of the pandemic. It is clear that at the moment in Europe we have managed to contain the impact of the epidemic to some extent because we have vaccines and treatments available. In particular, we have managed to avoid new lockdowns and curfews during the recent waves of the pandemic.

But we have not yet managed to avoid a high death rate linked to Covid-19: in France, 65,000 deaths were reported in 2020, 60,000 in 2021 and another 22,000 during the first four months of 2022, a fairly similar pace. What since the beginning of 2022. Epidemic. Because of the high susceptibility to the transmissibility of delta and then omicron variables, we decried the high mortality figures in recent months, in absolute numbers. But when vaccination coverage of the elderly and the frail was imperfect as in Hong Kong, Omicron did a great deal of damage there, both in terms of hospital overcrowding and deaths.

In the face of a potential new wave, two challenges must be faced: The first is to at least maintain this “armed peace” that allows properly vaccinated people to avoid severe forms of Covid-19 as much as possible and the vulnerable to effectively benefit from available treatments. The second, in the long term, is to address the transmission mechanisms of this respiratory virus. We know that it is transmitted mainly by aerosols in enclosed and poorly ventilated spaces, so it is advisable to improve indoor air quality in all enclosed spaces open to the public: homes, public transport, bars, restaurants and clubs, schools, universities and shared offices.

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