A sub-variant of the highly contagious Omicron Coronavirus strain is even more infectious than the original version, according to a Danish study.
Sub-variant BA.2 - also called "stealth Omicron" - was detected earlier this year and has displaced the first Omicron variant, known as BA.1, as the dominant strain in Denmark.
A person infected with BA.2 has a 39% chance of transmitting the virus to someone else in their household within a week, compared to a 29% risk with BA.1, Denmark's SSI health authority said in a statement.
The study by SSI researchers and Danish universities involved 18,000 people and was carried out between 20 December and 18 January.