The World Health Organization (WHO), in its weekly epidemiological report, announced Wednesday that 57 nations have reported COVID-19 Omicron cases so far.

Although it’s not clear whether the Omicron variant can lead to more severe COVID-19 symptoms, the U.N. health organization again said Wednesday that more data is needed to assess the severity of the disease, or whether its mutations can breach vaccines or natural immunity.

“Even if the severity is equal or potentially even lower than for Delta variant, it is expected that hospitalizations will increase if more people become infected and that there will be a time lag between an increase in the incidence of cases and an increase in the incidence of deaths,” WHO said in its report.