The Medical Officer of Health may at any time—
(a) Require any person who in his opinion has been recently exposed to the infection of smallpox to be forthwith vaccinated or revaccinated, or, if the person is a child, may require the parents or guardians to have such child forthwith vaccinated or revaccinated; and
(b) Require any such person to be isolated by remaining within any specified house or other place until the vaccination or revaccination has been successful, or until a period of 16 clear days has elapsed since such person was, in the opinion of the Medical Officer of Health, last exposed to the infection of smallpox.