How can we get a cold all winters if our immune cells recognize them. And it doesn’t kill them quick?

Question: How can we get a cold all winters if our immune cells recognize them. And it doesn't kill them quick?
- Keywords:
  cold,
  winter
Asked by George to Carmen, Laura, Steph on 19 Mar 2015.
- Stephanie Dyson answered on 19 Mar 2015:
  
  There are lots of different strains of the virus that gives us cold. When we get a cold of one strain the body treats it but then we get a different strain and get sick again. Because the body is constantly killing the virus it is running on a lower energy level so we are more prone to picking up other strains of the virus
  
  Steph
- Carmen Denman answered on 19 Mar 2015:
  
  Hi George,
  Steph is correct that battling one version of the rhinovirus doesn’t make us immune to other “flavours” of the common cold (it mutates rapidly between pockets of populations) however, in the winter in general, we spend more time indoors with lots of other people, hence spread of disease is quicker and easily accommodated in that sort of scenario.
  Cheers!
  Carmen

Question: How can we get a cold all winters if our immune cells recognize them. And it doesn't kill them quick?