Most COVID cases discovered recently in Shenzhen since Aug. 23 were identified having BF.15, a new mutation of the Omicron subvariant BA.5.2.1 while some other cases were identified having BA.5.2, BA.5.2.1 and BA.2.2, according to local health authorities.
BA.5 is a subvariant of Omicron and its sequence was first uploaded to GISAID (Global Initiative on Sharing All Influenza Data) on March 15, which was from a sample collected in South Africa, according to the Chinese Center for Disease Control and Prevention.
The Omicron sublineage BA.5 is a more contagious variant, it spreads faster and has an improved capability to escape the immune system, experts said.
The latest study in South Africa shows that BA.5 has an R0 value of 18.6, which is the most transmissible virus known today. Its transmissibility is six times greater than that of the original strain.
BA.5 has been found in over 100 countries and regions. Its subvariants have been detected in Chinese cities including Xi’an, Beijing, Qingdao, Dalian, Tianjin, Shanghai and Zhuhai.
The mutant COVID strain BA.5 is mainly spread through respiratory droplets and direct contact.
The incubation period of Omicron subvariants is from three to seven days in most cases, and four days clinically, according to the ninth version of COVID-19 prevention and control guidelines released by the National Health Commission.
The strain spreads to many asymptomatic infections, making it harder to detect early.
The most common symptoms of being infected with BA.5 are persistent cough, nasal congestion, sore throat and extreme fatigue. However, loss of taste and smell is no longer a common symptom, according to the Centers for Disease Control and Prevention in the U.S.
However, the pathogenicity of Omicron BA.5 hasn’t been significantly enhanced and the current prevention measures are still effective. In addition, data from South Africa showed that BA.5 resulted in less severe illnesses and death than the Delta variant, and vaccines can protect from severe illnesses and death.
Residents are advised to wear a mask, practice social distancing and maintain personal hygiene such as washing hands frequently.