China is warning it faces a steep surge in COVID-19 cases as the country rapidly dismantles pandemic controls and embraces a faster reopening than some experts had expected.

The sudden move away from 'zero-COVID' has left many people bewildered and a surge in infections is "surely unavoidable,” Zhang Wenhong, one of China’s top COVID-19 advisers, wrote in an opinion piece published by Caixin on Tuesday. The country will likely see a large initial peak, followed by significantly weaker second and third waves, he wrote, citing the experience of other countries.

The comments come after China scrapped almost all of its internal virus curbs last week, in a sudden U-turn that leaves only strict border controls as the last vestige of the zero-COVID policy that isolated the country for three years.