How long will our new vaccines be effective in warding off the SARS-CoV-2 coronavirus, given that viruses are always evolving into new variants or strains? And what kind of immunity will they give us in the meantime – the kind that prevents us from spreading the virus to others, or only the kind that prevents us from getting sick? Are some of us already immune to Covid-19 because of previous exposure to seasonal coronaviruses? What percentage of the population has to acquire immunity in order for the pandemic to finally end? These are some of the questions Jonathan asked molecular immunologist Vladimír Leksa, who has been studying the virus and our immune responses to it since the pandemic arrived in Europe nearly a year ago.