According to the report of the health times, on May 16, China reported the details of the first confirmed imported case infected with the novel coronavirus "Omicron" subtype "ba.2.12.1". On April 23, 2022, an international flight kq880 from Nairobi, Kenya arrived at Baiyun International Airport, Guangzhou, Guangdong Province. All passengers were transferred to the isolation hotel for 14 days of routine medical observation and routine nucleic acid testing**
One of the patients, a 27 year old Chinese male, reported positive for the nucleic acid of novel coronavirus on 27 April 2022. The patient had a complete history of novel coronavirus vaccination and had not been exposed to other cases of COVID-19 pneumonia in the past 14 days. After diagnosis, he was transferred to Guangzhou Eighth People's Hospital for treatment.
On April 30, 2022, the nasal swab samples of the patient were sequenced using Illumina miniseq platform. The genotyping results showed that the patient was infected with Omicron subtype ba 2.12.1。 A total of 33 amino acid mutation sites were detected in the spike gene. Where l452q and s704l are ba 2.12.1 key loci of sub lineage. The sequence has been submitted to the national genome data center.
On May 4, 2022, the World Health Organization reminded close monitoring of subtype ba 2.12.1。 Compared with other Omicron subtype strains, ba 2.12.1 subtype has stronger immune escape ability, and some studies have shown that ba 2.12.1 transmission rate ratio of Ba 2 fast 23% to 27%. The sub mutation spread very rapidly, resulting in a re epidemic in many parts of the United States, with cases reported in at least 17 countries**