A new Centers for Disease Control and Prevention study says booster shots of Pfizer's and Moderna's COVID-19 vaccines proved vital in keeping additional Americans out of the hospital as the omicron variant spread this month.

The real-world study says that the mRNA booster shots were 90% effective in preventing hospitalization as a result of the omicron variant.

Additional data released Thursday shows that Americans 50 and older who were not vaccinated were 17 times more likely to be hospitalized than fully vaccinated people.

Omicron, a highly contagious strain of COVID-19, has led to record-breaking case levels across the country. Scientists say that the variant has been found to better evade the body's immune response compared to past variants.

However, scientists like Dr. Anthony Fauci have said that omicron likely causes less severe cases of disease because it does not affect the lungs the way past variants did.

The findings come just weeks after the CDC changed its guidance and said that Americans should seek mRNA boosters five months after their second dose of the vaccine. Previous guidance said that Americans should seek a booster six months after a second dose.