International pediatric COVID-19 severity over the course of the pandemic by Zhu, Y, Almeida, FJ, Baillie, JK, Bowen, AC, Britton, PN, Brizuela, ME, Buonsenso, D, Burgner, D, Chew, KY, Chokephaibulkit, K, Cohen, C, Cormier, SA, Crawford, N, Curtis, N, Farias, CGA, Gilks, CF, von Gottberg, A, Hamer, D, Jarovsky, D, Jassat, W, Jesus, AR, Kemp, LS, Khumcha, B, McCallum, G, Miller, JE, Morello, R, Munro, APS, Openshaw, PJM, Padmanabhan, S, Phongsamart, W, Reubenson, G, Ritz, N, Rodrigues, F, Rungmaitree, S, Russell, F, Sáfadi, MAP, Saner, C, Semple, MG, Prado da Silva, DGB, de Sousa, LMM, Diogo Moço Souza, M, Spann, K, Walaza, S, Wolter, N, Xia, Y, Yeoh, DK, Zar, HJ, Zimmermann, P, Short, KR, Alex, B, Horby, PW