What can NZ do about Delta?

Is Delta more deadly, or just transmitting more rapidly? And are the vaccines we're using likely to defend against future coronavirus variants? Also, does it matter that levels of antibody dimish post-vaccination, or will immune memory make up for the shortfall? Meanwhile, are vaccinated people who still catch Delta equally infectious? How does sewage monitoring for coronavirus outbreaks work and is it effective? Is drinking water a risk for Covid-19 viral transmission? Does Delta incubate at the same rate as classical coronavirus strains? Do tests work equally well against Delta? Should children be vaccinated against Covid-19?