Pfizer, Moderna step up testing Omicron-specific vaccines

Pfizer and Moderna are stepping up trials of COVID-19 vaccines that specifically target the Omicron variant, as the highly contagious variant now accounts for 99.9 percent of new infections in the United States, reported Xinhua.

Pfizer and its partner BioNTech announced on Tuesday the initiation of a clinical study in up to 1,420 healthy adults aged 18 to 55, to evaluate the safety, tolerability and immunogenicity of an Omicron-based vaccine candidate.

The study will have three cohorts examining different regimens of the current Pfizer-BioNTech COVID-19 vaccine or an Omicron-based vaccine.

The Omicron-specific vaccine will be administered as a 30-microgram dose, the same as the current vaccine.

"While current research and real-world data show that boosters continue to provide a high level of protection against severe disease and hospitalization with Omicron, we recognize the need to be prepared in the event this protection wanes over time and to potentially help address Omicron and new variants in the future," said Kathrin U. Jansen, senior vice president and head of vaccine research and development at Pfizer.

A Pfizer spokesperson told CNN the company has already begun to manufacture this vaccine.

A day later, Moderna also announced it has begun dosing patients in a clinical trial testing its COVID-19 vaccine booster shot that is specific to the Omicron variant.