Agree. Because of the 'police officer', I would never tell them until after getting the medicine. It's not their right to know if it can get you killed or ostracized right away.
The police guy keeps trying to kill people or kick them out for any detail that would make them 'less valuable', 'outsiders', or the smallest potential 'threat'. If the girls told them, pink-haired girl wouldn't stand a chance, especially if the lack-of-resources situation continues and the number of people eventually needs to be reduced. People would immediately suggest pink-haired girl for her past or her potential to still be a carrier of the infection even if she is cured. They would still look down on her too - there's not only the judgmental nurse in the group, the fake doctor writer who tried to cause trouble just for fun, but also other selfish people there.
I'd keep it a secret, at least until after securing medicine and being cured. If someone does need to know, I'd tell oreum and plan with her how to spread the information without giving away what exactly happened to the others. But no one needs to know at the current moment (everyone is confirmed not infected and can stay safe in the house for a day while they get medicine).
And only oreum is both competent and trustworthy so far in this situation.
Only oreum. I would never trust the police officer.

I want this to be a yuri but I also need Dalrae to speak up, this is the second time that she knows something and could help the group because of the medicine (/TДT)/