Covid: Pfizer and Moderna vaccines against Omicron are allowed in the US

U.S. health authorities on Wednesday approved a new version of Pfizer and Moderna’s Covid-19 vaccine specifically for the Omicron variant in hopes of better containing a dangerous new wave of infections this winter.

Two updated vaccines are approved for the booster dose: from 12 years of age for the Pfizer vaccine and from 18 years of age for the Moderna vaccine, according to a press release from the American Medicines Agency (FDA).

This next-generation Covid vaccine, called bivalent, targets both the original coronavirus strain and the BA.4 and BA.5 lines of the Omicron variant. This last line currently represents almost 90% of infections in the United States.

“A new wave is expected as we spend more time indoors this fall and winter,” Robert Kaliff, head of the FDA, warned during a press conference, pointing out that it was “expectation” for this increase in pollution.

Even if the virus has largely disappeared from American daily life, there are still about 80,000 new cases and 400 deaths from Covid-19 in the United States every day.

Earlier this summer, the US Department of Health announced that it had purchased 105 million of these new doses from Pfizer and 66 million from Moderna.

These updated vaccines have not yet been recommended by the Centers for Disease Control and Prevention (CDC) prior to injection. The CDC is to convene a committee of independent experts to discuss this on Thursday. The agency’s director, Rochelle Walensky, will then be in charge of giving the final green light.

Both companies have indicated that the new doses are ready to ship, potentially being available as early as next week in the country.

It remains to convince the Americans to administer these new injections when only about half of the eligible people have already taken their first booster dose.

– “Restore” immunity –

For now, the initial vaccination will be offered alongside earlier vaccines to provide a “baseline” of immunity, Kaliff said.

Renewal boosters can be given two months after the previous dose (booster or initial vaccination). The dosage is 30 mcg for Pfizer and 50 mcg for Moderna.

The vaccines currently in circulation are currently only based on the original strain of the virus that emerged in Wuhan in China, but have gradually proven less effective against variants that have emerged over time due to the rapid evolution of the virus.

For its approval, the FDA relies, in part, on clinical trials conducted to evaluate another updated version of the vaccine using the BA.1 line. This version of the Moderna vaccine was licensed in the UK in mid-August.

Vaccines specifically using BA.4 and BA.5 have so far only been evaluated in preclinical animal studies.

But health authorities insist that this strain change does not in any way threaten the safety of the vaccines. “What we do here is what we do every year for the flu vaccine,” said Peter Marks of the FDA.

However, some US experts have raised questions about the degree of improvement in the effectiveness of these updated vaccines, which can only be measured through clinical trials.

The “hope” is to “restore” a level of immunity similar to that given by the vaccines when they were launched, and provide “a longer duration of protection” so that reminders don’t have to be repeated too often, Peter said. Tags.

Studies will be conducted to evaluate the real effectiveness.

Asked about the need to involve the young population in this massive recall campaign, Mr Marks stressed that these vaccines can help protect against the “long Covid” that affects all ages, in particular.

Pfizer and Moderna have also submitted an authorization request for an updated version of their vaccine to the European Medicines Agency (EMA).

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