Dr. Elizabeth Richardson, Hamilton's medical officer of health, had already implemented more stringent measures above and beyond red zone restrictions, including businesses having to screen customers before they enter retail stores. The decision to move the city in lockdown "wasn't an easy one, but a necessary one," she said in a media release Friday. Health officials say the virus is continuing to spread in workplaces and social settings. The doctor said public health continues to hear about people holding holiday gatherings and that staff has "definitely seen transmission" linked to them. 'Don't rush to the stores' Under lockdown, it's illegal to gather indoors with anyone who isn't a member of your household.