32. DESCRIPTION OF THE EPIDEMIOLOGICAL CHARACTERISTICS OF COVID-19 AND THE CAPACITY TO TRACK CLOSE CONTACTS OF THE DISEASE IN VAN DON DISTRICT, DONG TRIEU TOWN, QUANG NINH PROVINCE IN 2021. YHCĐ. 2025;66(CĐ3-HNKH Ký Sinh Trùng VN lần thứ 51). doi:10.52163/yhc.v66iCĐ3.2153