TAIPEI (Taiwan News) — The first local case of the COVID-19 Omicron BA.4 subvariant formed part of a family cluster, the Central Epidemic Command Center (CECC) said Thursday (Aug. 18).

Taiwan has so far counted two BA.4 and 58 BA.5 cases, with the latter expected to cause a rise in the daily number of local transmissions from next week, after several weeks when the number remained stable around 20,000.

A man in his 30s living in north Taiwan started showing COVID symptoms, including a sore throat, on Aug. 5, before testing positive on Aug. 9, CNA reported. The same day, he visited a hospital, where a PCR test turned out positive as well.

The man’s wife was asymptomatic but also received a PCR test result positive for COVID on Aug. 10, with gene sequencing confirming both had been infected with the BA.4 subvariant, the CECC said.

Sequencing for one of the couple’s two children, who had tested positive for COVID, had not been completed as of Thursday afternoon, though the CECC estimated the likelihood of BA.4 was high. The other child also tested positive for COVID, but because his Ct value was higher than 30, gene sequencing was not deemed necessary, the report said.