American health authorities on Monday approved an updated version of the Pfizer and Moderna vaccine from Covid 19, better adapted to the variants currently in circulation, AFP reports.

Both companies said their new version of the vaccine would be available for booster shots in the coming days, at a time when the number of hospitalizations related to Covid-19 in the United States is rising.

This new version was developed starting with variant XBB.1.5 and should “provide good protection against currently circulating variants of Covid-19,” the US Food and Drug Administration (FDA) said in a statement.

The two most common variants currently in use in the United States are EG.5 and FL.1.5.1.

Moderna said in a press release that its new vaccine, tested in humans, did indeed elicit an immune response against the two variants.

While the FDA has approved new versions of the vaccine starting at 6 months of age, another federal health agency, the Centers for Disease Control and Prevention (CDC), is set to hold a meeting on Tuesday to determine which populations should receive the recommended dose for reminder.

American experts are divided on whether the entire population should receive the new dose, or whether the focus should instead be on susceptible people, as is the case in Europe.

“We strongly encourage eligible individuals to consider vaccination,” FDA spokesman Peter Marks said in a statement Monday. “Vaccination remains important for public health and continued protection against the serious consequences of Covid-19, including hospitalization and death.”

The United States plans to conduct an annual vaccination campaign against Covid-19, each time with an adapted vaccine, just like for the flu. But the success of the new formula is unknown: only 17% of the American population received the previous booster dose.