The US pharmaceutical manufacturer Moderna has achieved promising results in a study with its further developed corona vaccine.

The bivalent booster vaccine, which targets both the beta variant and the original coronavirus, achieved a better immune response against a range of virus variants including omicron, Moderna said on Tuesday.

The vaccine produced higher neutralizing antibody titers against the omicron variant than the booster dose of the vaccine currently in use.

Bivalent vaccines immunize against two pathogens or two types of pathogens.

However, Moderna does not directly plan to apply for approval of the bivalent vaccine, including the beta variant, according to Jacqueline Miller, a leading Moderna scientist.

However, the data would be sent to the US Food and Drug Administration (FDA) to lay the groundwork for a future bivalent vaccine candidate that targets the omicron variant.

300 subjects took part in the study in the USA.

Moderna has also started testing another bivalent vaccine that combines an omicron-specific vaccine with its original.

The first data on this is to be published in the second quarter.

"To prepare for the fall, we had to start production at risk," Miller said.

"Our belief is that, based on the data we have already observed, the bivalent...offers the best hope for longer and more durable protection."