Well, it's very likely that the 1977 "russian flu" pandemic was caused by a Chinese lab leak during vaccine research [1]. https://theprint.in/science/lab-leak-

Well, it's very likely that the 1977 "russian flu" pandemic was caused by a Chinese lab leak during vaccine research [1]. https://theprint.in/science/lab-leak-is-the-biggest-suspect-in-1977-flu-pandemic-but-it-took-3-decades-to-gain-currency/669907/ https://theprint.in/science/lab-leak-is-the-biggest-suspect-...