Table II.

Risk categorization of contacts of COVID-19 patients in a hospital setting

	World Health Organization [26]	Centers for disease control and prevention [27]	Public Health England [28]	European centres for disease prevention and control [29]	Communicable disease network Australia [6]
Close/high- to medium-risk contact	(No explicit differentiation between close and casual contact) Contacts include provision of direct care for patients with COVID-19, or visiting patients or staying in the same environment as a patient with COVID-19, or working with HCWs with COVID-19 disease	Within 2 m of a person with COVID-19 for a prolonged period of time (>1–2 min). Taking into account the clinical syndrome patients (e.g., coughing) and whether patient wore facemask High risks: perform or present in the same room for AGPs when the HCW eyes, nose or mouth were not protected. Medium risks: perform or present in the same room for AGPs without using gown and gloves (but eyes, nose and mouth were protected), or HCWs with unprotected eyes, nose or mouth with prolonged close contact with patients with COVID-19 who was or was not wearing a facemask, or HCW with direct contact with secretion/excretion of COVID-19 patient without wearing gloves and failed to perform immediate hand hygiene	Face-to-face contact, or spending >15 min within 2 m of an infected person	Direct physical contact, or unprotected direct contact, or face-to-face contact within 2 m for >15 min, or closed environment for 15 min at a distance of <2 m as a COVID-19 case, or laboratory workers handling specimens from a COVID-19 case; AND without recommended PPE or with a possible breach of PPE	Face-to-face contact for >15 min in any setting with a confirmed case in the period extending from 24 h before onset of symptoms in the confirmed case, or sharing of a closed space with a confirmed case for >2 h in the period extending from 24 h before onset of symptoms in the confirmed case
Casual-/low-risk contacts		HCW wearing a facemask or respirator only and have prolonged close contact with a patient who was wearing a facemask, or HCW using all recommended PPE (i.e., a respirator, eye protection, gloves and a gown) while caring for or having contact with the secretions/excretions of a patient, or HCW (not using all recommended PPE) who have brief interactions with a patient regardless of whether patient was wearing a facemask (e.g., brief conversation at a triage desk; briefly entering a patient room but not having direct contact with the patient or their secretions/excretions; entering the patient room immediately after they have been discharged)	Not defined	Person in a closed environment with a COVID-19 case for <15 min, or at a distance of more than 2 m, or a person having had face-to-face contact with a COVID-19 case for <15 min and at within 2 m	<15 min face-to-face contact with a symptomatic confirmed case in any setting, or sharing a closed space with a symptomatic confirmed case for less than 2 h
Management	Monitor health and symptoms for 14 days from the last day of contact	High- and medium-risk: work exclusion of HCWs and medical surveillance for 14 days after last exposure Low-risk: self-monitoring with delegated supervision until 14 days after the last potential exposure	Work exclusion and home quarantine for 14 days following the last possible contact with the case	High-risk contact: work exclusion and medical surveillance for 14 days from the last possible day of contact; avoid social contact and travel Low risk contact: self-monitoring and self-isolation if respiratory symptoms are experienced; NO suspension from work.	Work exclusion and home quarantine for 14 days from the last possible day of contact
Testing for SARS-CoV-2	If fever or respiratory symptoms consistent with COVID-19 develop during the 14-day surveillance period

AGP, aerosol-generating procedures (e.g., open suctioning of respiratory tract, intubation, bronchoscopy, cardiopulmonary resuscitation); COVID-19, coronavirus disease 2019; HCW, healthcare worker; PPE, personal protective equipment.