The head of the World Health Organization (WHO) warned against describing the Omicron variant as "mild" amid a "tsunami of cases" overwhelming health systems across the world.
"Last week, the highest number of COVID-19 cases were reported so far in the pandemic," Dr. Tedros Adhanom Ghebreyesus told reporters during a regular press briefing.
The UN agency's latest weekly report showed that a record 9.5 million COVID-19 infections were reported across the world over the previous week - a 71 percent increase on the previous seven-day period.
All regions reported a surge in the number of COVID-19 infections with the largest increase (100 percent) observed in the Americas, followed by South-East Asia (78 percent) and Europe (65 percent).
Yet, the WHO chief stressed that "we know, for certain, that this is an underestimate of cases because reported numbers do not reflect the backlog of testing around the holidays, the number of positive self-tests not registered, and burdened surveillance systems that miss cases around the world."
Omicron, first detected in South Africa in November, has been blamed for the latest wave. The variant was designated "of concern" by the WHO because studies show it is more transmissible and more resistant to treatment than other variants, including Delta, with people more likely to be infected or reinfected even when fully vaccinated.
