What makes a perfect virus?

This is an example of a scientific question at an Oxbridge medical interview. The purpose of this type of question is to assess whether you have the ability to work something unfamiliar from first principles. They are not testing your knowledge per se, but rather whether you can build upon what you know to come up with a logical answer. Let me show you how to approach this type of question by using this one as an example. I was asked this during one of my interviews at Oxford. The way to approach it is to start from the basics. What does a virus need to survive? Suitable host environment, Optimum temperature and pH, Access to food & nutrients What qualities should this virus possess?The ability to lower the hosts’ defences enough so that it can enter and survive within the host, but not enough to kill it & The ability to effectively avoid detection by the host’s immune systemThis is an example of how you could talk through the question out loud with the interviewer. At this point, the interviewer then asked if I could name any viruses that fit my description and were close to being perfect. I said no! In actual fact, this description fits that of Epstein Barr virus, which is an arguably “perfect” human virus, as it is carried mostly asymptomatically by 9 out of 10 of the world’s adults. This highlights an important point – the purpose of this question wasn’t to test if I could recall random facts, but whether or not I could approach a completely unknown topic logically and try to make some sense of it.