The spread of Covid-19 in China is now “impossible” to track, the country’s health authorities have said, announcing they have stopped recording asymptomatic cases in their daily tallies. The admission comes amid soaring presentations to hospitals and clinics as Covid-19 spreads rapidly through the population in the wake of the sudden removal of strict pandemic measures. Authorities have urged people not to seek emergency healthcare unless necessary, and announced the rollout of second boosters to elderly and vulnerable people. China’s government abruptly ended the long-running and strict zero-Covid policy last week, rolling back measures including travel restrictions and lockdowns. Health...