From left: 1) Colored scanning electron micrograph (SEM) of a human cell infected with H3N2 flu virus (gold filamentous particles). 2) Scanning electron micrograph of human respiratory syncytial virus (RSV) virions (colorized blue) that are shedding from the surface of human lung epithelial cells. 3) Transmission electron micrograph of SARS-CoV-2 Omicron virus particles (gold). (Science Source/ NIAID)
