The World Health Organization (WHO) warned member nations earlier this week that the new Omicron variant is spreading faster than any previous COVID-19 strain.

"Omicron is spreading at a rate we have not seen with any previous variant," said WHO Director-General Dr. Tedros Adhanom Ghebreyesus during an agency press briefing on Tuesday. "Seventy-seven countries have now reported cases of Omicron. And the reality is that Omicron is probably in most countries, even if it hasn't been detected yet."

Tedros said the WHO is concerned that countries are not responding to Omicron as seriously as they should due to early reports concluding that the variant yields a mild infection, saying that the world has learned by now that "we underestimate this virus at our peril".

Tedros continued that even if Omicron, which has proven to be highly infectious, does cause less severe infections, "the sheer number of cases could once again overwhelm unprepared health systems", and bring the world right back to the early stages of the pandemic all over again.

Moreover, Tedros reiterated the agency's stance that COVID vaccines are being distributed inequitably around the world--with wealthier nations vaccinating most of their adult populations while poorer nations struggle to vaccinate even their high-risk citizens--highlighting that current COVID vaccine efficiency rates are hindered by Omicron.

"I need to be very clear: vaccines alone will not get any country out of this crisis," Tedros said. "Countries can--and must--prevent the spread of Omicron with measures that work today. It's not vaccines instead of masks. It's not vaccines instead of distancing. It's nots vaccines instead of ventilation or hand hygiene. Do it all. Do it consistently. Do it well."

Tedros added that the WHO is concerned that wealthy nations launching booster shot campaigns for their entire adult population will only increase global vaccine inequity.

"It's clear that as we move forward, boosters could play an important role, especially for those at highest risk of severe disease," Tedros said. "Let me be very clear: WHO is not against boosters. We're against inequity. Our main concern is to save lives, everywhere."

"Giving booters to groups at low risk of severe disease or death simply endangers the lives of those at high risk who are still waiting for their primary doses because of supply constraints," Tedros added. "On the other hand, giving additional doses to people at high risk can save more lives than giving primary doses to those at low risk."

Currently roughly 3% of sequenced new infections in the United States are caused by the Omicron variant, according to data compiled by the U.S. Centers for Disease Control and Prevention (CDC). The Delta variant is still the predominant COVID strain in the country, accounting for about 98% of all new infections, CDC data shows.