Though the article says: >[Health Secretary Matt Hancock] said there was "nothing to suggest" it caused worse disease or that vaccines would no longer work. I

Though the article says: >[Health Secretary Matt Hancock] said there was "nothing to suggest" it caused worse disease or that vaccines would no longer work. I do wonder in general about the "herd immunity" strategy and the likelihood that a worse strain or one that's resistant to the current vaccines comes along. I assume that the probability of mutation is basically proportional to the number of people who are infected by SARS-CoV-2. So, in addition to all the usual reasons why letting the virus spread freely until most of the population develops immunity (for some unknown length of time) is a bad idea, it seems like the spread of the virus is also setting up optimal conditions for the virus to evolve into something different or worse. I'm not an expert though, and I imagine there are probably other factors I'm not aware of besides number and severity of infections in determining whether a virus evolves or not.