TAIPEI (Taiwan News) — Taiwan's first cluster infection of the BA.5 subvariant of Omicron has been detected among a family in Taichung City.

The Taichung City Government Health Bureau announced in a July 6 press conference that the index case of the cluster is a woman in her 30s and Cases A and B are her children, who she brought back with her to Taiwan from the U.S. and are under the age of 10. Cases C and D are the index case's mother and brother, who picked the index case and her children up from the airport and are in their 50s and 30s, respectively.

Chen Li-chuan (陳麗娟), deputy director of the Taichung City Government Health Bureau, said that the index case had brought her children back to Taiwan from the U.S. on June 19. When she arrived in Taiwan, she already had symptoms of the virus, including a fever and cough, and tested positive at the airport with a Ct value of 27.

The woman and her two children were taken to a quarantine hotel by her older brother and mother on that same day. Both children developed a fever on June 23 and were diagnosed with COVID after testing positive. Their Ct values were 25.5 and 29.2, respectively.

On June 24, the older brother of the index case also developed a fever and cough and received positive results on a rapid antigen test, and is now designated as Case C. A friend of Case C who was found to be a contact tested negative for the virus and is currently undergoing self-health monitoring.

Although asymptomatic, the index case's mother tested positive for the virus and has been designated as Case D. On July 5, Taichung's health bureau received notification that genetic sequencing had revealed that all five cases had been infected with the BA.5 subvariant.

According to Taichung Deputy Mayor Bruce Linghu (令狐榮達) only one family member is still undergoing quarantine, while the others have been released. He advised the public that the probability of serious illness caused by the BA.4 and BA.5 subvariants of Omicron is not significantly higher, but they have a higher level of contagiousness.

He added that increasing the COVID vaccine coverage rate in the country can reduce the threat of community transmission posed by BA.4 and BA.5 and called on the public to complete their COVID vaccinations as soon as possible.

Chart showing Omicron BA.5 cluster infection. (Taiwan News, Yuwen Lin image)