With the global average of new cases of Covid-19 having scaled new highs this week, the World Health Organisation has warned that the rapid spread of the Omicron variant of the virus, while the Delta variant continues to circulate, is leading to a tsunami of infections. In some countries, particularly in Europe, there is concern that health systems could, like last year, again be overwhelmed. Many have ordered closures of public venues and tighter travel restrictions. In Asia too, some cities, including in China, India and Thailand, are battling a resurgence of infections and either imposing lockdowns or tightening borders and curbs on movement.

Nevertheless, the health impact of the new waves of infections has, thus far, not appeared to be as or more serious than previous waves. Preliminary evidence suggests the Omicron variant causes milder forms of illness, often not requiring hospitalisation, particularly in vaccinated individuals. However as the most transmissible variant so far and partially resistant to vaccines, it does lead to higher numbers of infections.