Immutable fact: You need both a vaccine and a mask × Amid the uncertainties over mutant strains and a possible second wave of infections, what’s certain is the need for continued vigil A second wave of Covid-19 infection seems to be setting in in India. This raises a number of questions. Is this second wave due to mutations in the SAR-CoV-2 virus? To what extent does vaccination help? Is there any point in getting vaccinated if mutated viruses can still attack us? There are no sharp answers yet — experts will likely proffer a ‘yes, but’ kind of reply. For instance, there is no clear evidence that the second wave is due to mutated viruses, but you never know.