18th March 2023 – (Chongqing) According to the latest weekly report published by the National Health Commission, a case related to COVID-19 was detected in a sample collected and tested on 14th February at the Third Affiliated Hospital of Chongqing Medical University. The 67-year-old female patient living in Yunyang County, Chongqing City had reported poor appetite on 23rd December of last year, followed by fatigue and cough on 29th December. The COVID-19 test result was positive. On 4th January of this year, the patient showed symptoms such as fever and cough. From 6th January to 12th February, eight nucleic acid tests showed positive results. The patient had received two injections of the coronavirus disease 2019 (COVID-19) vaccine (Sinovac Life Sciences Co. Ltd.).
Respiratory samples were collected from the patient on 28th January and 7th February, named YB20230158 and YB20230202 respectively. These two samples formed an independent branch, distinct from the Omicron sub-variants BA.5.2.48 and BF.7.14. Mutation site analysis showed that both samples contained specific defining mutation sites of Omicron sub-variants BA.5.2.48 and BF.7.14, indicating that the patient was simultaneously infected with both sub-variants, which is the first of its kind in China. BA.5.2.48 and BF.7.14 are also the two major virus strains prevalent in Chongqing.
In the investigation, her family members and neighbours were found to be infected in late December, suggesting a potential exposure. During her two hospitalisations, she may have come into contact with other individuals infected with the SARS-CoV-2.
Researchers warned that with the increasing risk of various variants co-circulating in one region, monitoring of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, particularly of immunocompromised individuals, is becoming increasingly important. As per the latest “National Report on the Epidemic of SARS-CoV-2 Infection” published by China CDC, the primary SARS-CoV-2 strain prevalent in Chongqing is BA.5.2.48, accounting for more than 90% of the cases, followed by BF.7.14, which is approximately 3.8%. There have been no documented cases of co-infection with BA.5.2.48 and BF.7.14 in China, especially in Chongqing, where the proportion of BF.7.14 is relatively low, rendering the finding more significant. It is imperative to promote the surveillance of SARS-CoV-2 variants as a crucial strategy to detect co-infections and recombination cases. With the constant increase in the risk of various SARS-CoV-2 variants co-circulating in a specific area, the monitoring of SARS-CoV-2 variants, particularly for individuals with compromised immune systems, has become increasingly vital.