In a government statement about the latest Covid-19 outbreak in China’s Kashgar city on Tuesday, there were five confirmed cases but a further 178 without symptoms tested positive . The seemingly contradictory report relates to China’s unique definition of Covid-19 confirmed cases, which excludes positive patients who are asymptomatic or presymptomatic. The 178 people who tested positive are not counted as confirmed cases, although some will be included later when they show symptoms. China’s controversial definition sparked concerns , particularly in Wuhan in March when residents heard about positive cases in their neighbourhoods while the tally of confirmed cases did not change. China began to release figures counting asymptomatic cases from April. But they are not counted as confirmed cases unless they develop symptoms or lung imaging is abnormal. By late February, the South China Morning Post had learned about a third of positive cases were silent carriers or presymptomatic patients. But it is unclear how many asymptomatic cases China has had so far because accumulated figures were never released. China is the only country in the world to adopt a different definition than that of the World Health Organization , which defines a confirmed case as someone who tested positive. A third of virus cases may be ‘silent carriers’, classified data suggests Chinese officials argued early in the pandemic that the number of true asymptomatic cases was small and “there was no evidence” they could spread the disease. But 10 months into the pandemic these arguments no longer stand. Data shows that asymptomatic cases comprise a significant percentage of the total positives and such patients spread Covid 19. In September, the Korea Disease Control and Prevention Agency said up to 40 per cent of Covid 19 patients in that country were asymptomatic. Many countries warned that asymptomatic transmissions were the cause of their coronavirus surges. Kashgar officials said all the most recent cases were linked to a teenager but patient zero in the cluster has not been identified. The asymptomatic cluster is evidence of asymptomatic transmissions. Fully aware of the risks, the government tested 4.75 million people in two days. Given that asymptomatic cases are also contagious and their percentage is significant, China should include them among confirmed cases to align with global practice. If China wants to distinguish, it can specify asymptomatic cases in its total tally as Japan once did. Now, Japan releases one tally of positive cases which includes – but does not differentiate – asymptomatic cases because they are, after all, Covid-19 cases.