Background Non-pharmaceutical measures and travel restrictions have halted the spread of coronavirus disease 2019(COVID-19)and influenza.Nonetheless,with COVID-19 restrictions lifted,an unanticipated outbreak of the influ-enza B/Nictoria virus in late 2021 and another influenza H3N2 outbreak in mid-2022 occurred in Guangdong,southern China.The mechanism underlying this phenomenon remains unknown.To better prepare for potential influenza out-breaks during COVID-19 pandemic,we studied the molecular epidemiology and phylogenetics of influenza A(H3N2)and BNictoria that circulated during the COVID-19 pandemic in this region.Methods From January 1,2018 to December 31,2022,we collected throat swabs from 173,401 patients in Guang-dong who had acute respiratory tract infections.Influenza viruses in the samples were tested using reverse tran-scription-polymerase chain reaction,followed by subtype identification and sequencing of hemagglutinin(HA)and neuraminidase(NA)genes.Phylogenetic and genetic diversity analyses were performed on both genes from 403 samples.A rigorous molecular clock was aligned with the phylogenetic tree to measure the rate of viral evolution and the root-to-tip distance within strains in different years was assessed using regression curve models to determine the correlation.Results During the early period of COVID-19 control,various influenza viruses were nearly undetectable in respiratory specimens.When control measures were relaxed in January 2020,the influenza infection rate peaked at 4.94%(39/789)in December 2021,with the influenza B/Victoria accounting for 87.18%(34/39)of the total influenza cases.Six months later,the influenza infection rate again increased and peaked at 11.34%(255/2248)in June 2022;influenza A/H3N2 accounted for 94.51%(241/255)of the total influenza cases in autumn 2022.The diverse geographic distribution of HA genes of B/Nictoria and A/H3N2 had drastically reduced,and most strains originated from China.The rate of B/Victoria HA evolution(3.11×10^(-3),P<0.05)was 1.7 times fast
The two-year"Masterpieces in Miniature"tour across seven major museums in China has fully demonstrated the role of museums as grand platforms for intercultural dialogue and the blending of world civilizations.This tour has successully opened a new chapter in cultural exchanges between China and the UK,contributing to global museum collaboration and the mutual enrichment of world civilizations.