“Have I had coronavirus and, if so, am I immune?” It’s the question many of us are asking – but sadly it isn’t an easy one to answer. Immunity is defined as being able to resist a particular disease.

Covid-19 continues to spread across the country, with huge numbers of people still testing positive for the virus every day. According to the latest available government data, in the last week, ...

Measles may seem like a disease of the past. Indeed, the highly contagious virus was declared eradicated in the United States in 2000 after a full year had passed without any infections. But times ...