Ung, T. thi H.; Hoang, P. V. M.; Nguyen, S. V.; Nguyen, H. L. K.; Nguyen, P. thi K.; Phan, D. T.; Le, T. T.; Nguyen, A. P.; Nguyen, T. C.; Hasebe, F.; Le, M. thi Q. Occurrence of the Omicron Variant of SARS-CoV-2 in Northern Viet Nam in Early 2022. Western Pac Surveill Response J 2022, 13, 5.