> Lockdown measures had not managed to stop ordinary colds and respiratory illnesses, such as rhinoviruses - which had dropped slightly during lockdown but bounced back soon after. "A lot does come down to their reservoirs and some are so well-adapted for humans and they're so widespread in the population that they are not affected a great deal by the lockdown."

Can anyone explain why colds have not come down as well? I don't understand what they mean by reservoirs.

As a related question, I've read that we all have cold viruses inside of us all the time, and they can be triggered by an immune weakness (such as by being in the cold outside). I've also read that you get a cold only because the virus is transmitted to you from someone else (which is more likely in the cold months when we're huddled together). Which is it? Can you develop a cold from a pre-existing internal virus with zero contact from another person?