Question: Why is it really dangerous if we get a virus from someone from another country or continent?

Matthew Lam answered on 11 Mar 2014:

As a general rule, I wouldn’t say it was any more dangerous than if you picked up the same virus from someone from the UK. But it depends what the virus is!

That said, different populations tend to have been exposed to different types of bacteria or viruses so every population of people will be different in the way their immune systems have developed to fight certain infections.

For example, if a person from a country where they had never been exposed to a flu virus came to a country like England where there is a lot of flu virus, then they would be much more likely to get the flu than the average person in England.