More than six in 10 people infected with the novel coronavirus generated neutralizing antibodies just two weeks after the onset of symptoms of the disease, but this neutralizing capacity decreases after six weeks, according to researchers at the Centre de recherche du Centre hospitalier de l’Université de Montréal, (CRCHUM).

Canada Research chair in retroviral entry and professor at Université de Montréal, Andrés Finzi, said in a statement that “a few booster shots of the vaccine may be necessary to protect the population in the long term.”

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In a non-peer-reviewed study posted on the bioRxiv prepublication server, Finzi’s team evaluated the capacity to neutralize plasma — the liquid component of blood containing antibodies — one, two, three and six weeks after the onset of symptoms of the disease.

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The team used plasma samples from 108 patients, healthy, infected or convalescent, provided by Héma-Québec and the Laboratoire de santé publique du Québec.

The researchers found that after three weeks,