TAIPEI (Taiwan News) — The Central Epidemic Command Center (CECC) on Friday (July 22) announced the country's first reported case of the BA.2.75 subvariant of Omicron, also known as "Centaurus."
With the resurgence of the global COVID pandemic, in addition to the rise of the Omicron BA.4 and BA.5 subvariants, the BA.2.75 subvariant is emerging in many countries. Philip Lo (羅一鈞), deputy head of the CECC's medical response division, said the man is in his 30s from northern Taiwan and received three doses of COVID vaccine.
On July 10, he arrived in Taiwan from India with two travel companions. Although they all tested negative for COVID before the flight, they all developed a fever and tested positive for the virus upon arrival in Taiwan. Their Ct values were all 20.
Lo said that after genetic sequencing was conducted, the man was found to have been infected with BA.2.75, while his two travel companions were infected with BA.4. He said that this indicates that there are probably multiple subvariants circulating in India.
All three have been released from isolation, and they did not come into contact with other people or enter the community during the quarantine period. Therefore, the CECC believes that the man did not transmit the subvariant to the community.
Lo said BA.2.75 is one of the subvariants that has recently drawn worldwide attention for being highly contagious. Twitter user Xabier Ostale on July 1 dubbed the subvariant "Centaurus" and the name has stuck.
BA.2.75 was first discovered in India in May of this year and has 16 more mutations than BA.2, primarily clustered on the spike protein. Because most of the mutations are clustered in the spike protein, which is the target for vaccines and the main impetus for the body to produce antibodies, international experts have raised alarms that the mutations could diminish the effectiveness of vaccines and lead to increased transmissibility.
Lo said that BA.2.75 has spread rapidly in India and is now transmitting faster than BA.5, according to Rajendram Rajnarayanan, PhD, an assistant dean of research and associate professor at Arkansas State University. Cases of Centaurus have also been reported in 15 other countries, including the U.K., Germany, the U.S., Canada, Australia, New Zealand, Japan, Indonesia, and Thailand.
He said that according to the World Health Organization, BA.2.75 is a new subvariant, which may affect immune escape, but whether transmissibility and probability of severe infection are increased remains to be seen.
The CECC official also emphasized that vaccination can still reduce the risk of severe illness, hospitalization, or death due to a COVID infection. He called on the public to complete all their COVID vaccinations as soon as possible to strengthen their immunity to the virus.