Uv rays can stop the spread of chickenpox which means that people in milder climates are at a higher risk of the disease.

Lead author of the study, Dr Phil Rice said, "No-one had considered UV as a factor before, but when I looked at the epidemiological studies they showed a good correlation between global latitude and the presence of the virus."
The study is published in the biology journal Virology.
Source-Medindia