COVID-19: Monoclonal antibodies ineffective against variants

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Monoclonal antibody treatments are proving ineffective against increasingly dominant new variants of COVID-19, the European Medicines Agency (EMA) warned on Friday.

• Read also: Call for a jump in vaccination against COVID-19 in France

Numerous monoclonal antibodies, given in hospitals by injection or infusion, targeting the spike protein of the virus, helped cope with the peak of the wave.

But, for the EMA, they “no longer seem to be effective against new strains” or variants.

Laboratory tests show that they prove to be “not very effective against the Omicron BA.4.6, BA.2.75.2 and XBB variants”, underlined in a press release the European agency based in The Hague.

“They also fail to significantly neutralize (variants) BQ.1 and BQ.1.1, which are expected to become the dominant strains within the EU over the next few weeks.”

The main antibody-based treatments are Evusheld from AstraZeneca, Ronapreve from Roche and Xevudy from GSK and Vir laboratories.

Antiviral treatments such as Paxlovid from Pfizer laboratories should however remain effective, according to the EMA.

Monoclonal antibodies initially managed to reduce the risk of hospitalization and death by 80%, but they became less effective as the virus mutated.

The WHO had recommended in September to stop using Xevudy and Ronapreve considering that they were no longer effective against new variants.

The EMA had in September and October approved the Pfizer/BioNTech and Moderna vaccines against types BA.4 and BA.5, in people who had already received their first dose.

The regulator had clarified on Tuesday that the two vaccines could now “be used for primary vaccination”.

While previous variants like Alpha and Delta eventually faded away, Omicron and its sub-lines dominated throughout 2022 and are expected to remain on top in 2023.

In particular, types BA.4 and BA.5 have contributed to an increase in the number of new cases of the disease in Europe and the United States in recent months.

All Omicron variants tend to result in slower disease progression, as they settle less in the lungs and more in the upper airways, causing symptoms such as fever, fatigue, and loss of smell.

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