“isolation” in relation to a person means the separation of that person from any other person in  in such a manner as to prevent infection or contamination (with Coronavirus)—  “medical officer” means a registered medical practitioner designated for the purposes of these  Regulations by the Secretary of State;  “Public Health England” means the executive agency of that name of the Department of  Health and Social Care;  “public health officer” means a registered public health consultant or a person working within  Public Health England under the oversight of a registered public health consultant;  “registered public health consultant” means a professionally registered public health  consultant working within Public Health England;  “responsible adult” means, in relation to a child, a person with parental responsibility for the  child (within the meaning of the Children Act 1989) or a person who has custody or charge of  the child for the time being; and  “screening requirements” means the requirements set out in regulation 6(1).  (2) In these Regulations, a reference to infection or contamination( a ), however expressed, is a  reference to infection or contamination with Coronavirus, and related expressions are to be  construed accordingly.  (3) The notice referred to in the definition of “infected area” and “isolation” in paragraph (1)  must be followed by publication of the notice in the London Gazette as soon as reasonably  practicable.  3. —(1) These Regulations apply where the Secretary of State declares, by notice published on  www.gov.uk, that the incidence or transmission of Coronavirus constitutes a serious and imminent  threat to public health, and that the incidence or transmission of Coronavirus is at such a point that  the measures outlined in these Regulations may reasonably be considered as an effective means of  preventing the further, significant transmission of Coronavirus (“serious and imminent threat  declaration”).  (2) The Secretary of State may revoke a serious and imminent threat declaration by way of a  subsequent notice published on www.gov.uk.  (3) Before making a declaration under paragraph (1), or revoking a declaration under paragraph  (2), the Secretary of State must have due regard to any advice from the Chief Medical Officer or  one of the Deputy Chief Medical Officers of the Department of Health and Social Care.  (4) The publication of a notice under paragraph (2) does not affect the validity of any steps taken  pursuant to these Regulations before the notice is published.  (5) A notice published under paragraph (1) or (2) must be followed by publication of the notice  in the London Gazette as soon as reasonably practicable.  4. —(1) Where Condition A or B is met in relation to a person (“P”), the Secretary of State or a  registered public health consultant may, for the purposes of screening, assessment and the  ( a ) See section 45A of the 1984 Act for the interpretation of “infection” and “contamination”. Section 45A was inserted by  section 129 of the 2008 Act.  Detention of persons by the Secretary of State or a registered public health consultant  Serious and imminent threat declaration  (a) at a facility designated, by notice published on www.gov.uk, for the purposes of these  Regulations by the Secretary of State;  (b) in that person’s home;  (c) in a hospital; or  (d) at another suitable place;  2