More evidence is emerging that the Omicron coronavirus variant is affecting the upper respiratory tract, causing milder symptoms than previous variants, a World Health Organisation official (WHO) said.

“We are seeing more and more studies pointing out that Omicron is infecting the upper part of the body. Unlike the other ones, that could cause severe pneumonia,” WHO Incident Manager Abdi Mahamud told Geneva-based journalists, saying it could be “good news”.

However, he added that Omicron's high transmissibility means it will become dominant within weeks in many places, posing a threat in countries where a high portion of the population remains unvaccinated.