Covid-19 Vaccine may be less effective against Omicron; WHO

The World Health Organization said on Wednesday that preliminary research suggests Covid-19 vaccinations may be less effective against infection and transmission linked to the Omicron coronavirus strain, which also carries a higher risk of reinfection.

More data is needed to better understand the extent to which Omicron may circumvent protection gained from immunizations or past infection, according to the WHO's weekly epidemiological bulletin.

"As a result of this, the total risk associated with the new variety of concern Omicron remains extremely high," it stated, repeating WHO officials' warnings from an online briefing on Tuesday.

"Omicron is spreading at a rate we haven't seen with any other variant," Tedros said in an online press conference. "Even if Omicron causes less severe disease, the sheer volume of cases could overwhelm health systems that aren't prepared."

Since the Omicron version surfaced last month, Pfizer-COVID-19 BioNTech's vaccine has been less effective in keeping patients infected with the virus out of hospitals in South Africa, according to a real-world study released on Tuesday.