(Reuters). Moderna Inc stated Wednesday that it was in the middle of a study to determine if a booster dose from its COVID-19 vaccine is safe and effective against Omicron coronavirus. The test came a day following a similar announcement by rivals. Pfizer Inc (NYSE) initiated a similar trial.

According to the company, while the original coronavirus vaccine was effective in increasing neutralizing antibodies at lower doses of the variant, a third dose increased their level six months later.

But neutralizing antibodies were still detectable in every participant. Moderna (NASDAQ:) said.

Omicron has been shown to have a lower severity of COVID-19 in comparison with previous waves. However, it is quickly becoming a dominant variant in many countries around the globe, driving up infection rates and stressing the healthcare system.

The COVID-19 case in the Unites States currently includes 99.9% of this variant.

Pfizer started Tuesday a clinical trial with BioNTech as its partner to assess a vaccine version specifically designed to be used in Omicron.

Moderna announced that they would be studying the Omicron booster in adult 18-year-olds.

The company stated that it would be testing the booster on individuals who had received Moderna’s first vaccine in a two-dose series, as well as those who were given both the primary series and the booster.

Moderna expects 300 participants to each group.

The U.S. Centers for Disease Control and Prevention led three studies that showed that a third dose (such as the Moderna and Pfizer) of an mRNA vaccination is crucial for fighting the Omicron variant.

Some countries already offer booster doses. A recent Israeli study found that even though a fourth dose was effective in increasing antibodies, it wasn’t enough to stop an Omicron infection.