Are coronavirus vaccines working? What the real world tells us

Delta, the strain first reported in India in October, is the most worrisome detected so far

With Covid-19 shots in billions of arms by now, evidence is emerging of how well they work in real-world settings. Vaccines authorised for emergency use have successfully subdued epidemics in nations where at least half of the population is fully immunised. But as more-transmissible variants spread, driving fresh outbreaks and an increase in breakthrough infections, health authorities are recommending some immunised individuals wear face-masks indoors to augment the protection of vaccines.

How good are Covid vaccines?

In general, the Covid shots are extremely good, though not perfect, at protecting ag­ainst hospitalisation and death. Rese­ar­c­h­ers in Taiwan found that a 10 per cent