GFAP and infection: In our study, we first demonstrated that influenza virus (H1N1-WSN) could widely infect multiple cell types in brain organoids, including SOX2+ neural stem cells (NSCs), MAP2+ neurons, and GFAP+ astrocytes, and holds an infection tropism of MAP2+ neurons (Figure 2), which may support a direct link between influenza virus infection and the neurologic symptoms.