Omicron subvariants BA.4 and BA.5 will soon dominate in HK, says health expert

The Omicron subvariants BA.4 and BA.5 will soon dominate in Hong Kong, but residents do not need to worry, said Ivan Hung Fan-ngai, an infectious disease expert at the University of Hong Kong.

His comments came as Hong Kong on Sunday recorded 1,681 local infections and 147 imported cases. Among them were 28 carrying the Omicron BA.4 or BA.5 subvariants and 23 BA.2.12.1 cases.

Speaking to a radio program on Monday, Hung said local data have suggested that at least 4 million people in Hong Kong have contracted the Omicron subvariant BA.2 in the city’s fifth wave of Covid outbreak.

The health expert said those who recovered from it are mostly protected against reinfection with BA.4 and BA.5.

“Hong Kong has also achieved herd immunity with the high level of vaccination rate to prevent further outbreaks,” he added.

Meanwhile, he noted that despite BA.4 and BA.5 are more infectious than past strains, they are less likely to cause more severe diseases, which would not be posing any threats to Hong Kong’s healthcare system.

When asked about the clinical trial conducted by the University of Hong Kong and Sinopharm on the Omicron-targeting vaccine, Hung said some 600 adult volunteers from a total of 1,300 have already received their first jab, with some having received two doses.

He said some of the volunteers have experienced common side effects including fatigue and fever after receiving the next-generation vaccines, similar to those who took the Sinovac vaccine. 

No volunteers have developed serious side effects after receiving the new vaccine, he added.

The expert said details of the clinical trial - including the immune responses granted by the new vaccine will be released after the completion of the study, with the vaccine expected to be available in the city in December this year.