How long does Covid-19 vaccine immunity last?

This week we join young learners at Christel House school who ask us about the duration of immunity to Covid-19 post-vaccine and post-infection. Also, menstrual synchrony and whether it's fact or fiction, craniofacial abnormalities and the developing baby, the threat humans face from Artificial Intelligence (AI), why we're conscious and why we sleep. Dr Chris Smith and Lester Kiewit have the answers...