CXCL2 and infection: In our study on H1N1 secondary infection during the convalescent stage of SARS-CoV-2 infection, we found that the abundance of many pro-inflammatory factors such as IL-1β, IL-6,TNF-α and GM-CSF, chemokines such as CXCL-1, CXCL-2, CXCL-5 and CXCL-13, antivirus cytokines such as IFN-βand IFN-γ, and anti-inflammatory factors such as IL-4 and IL-10 were higher on 7 dpi after H1N1 infection.