Thanks for taking the time to track the article down!
Anyone taking the time to actually read the article will understand the 80% is a very fluffy number from the WHO and there are other reported studies showing the asymptomatic portion of the those actually contracting the COVID-19 virus is somewhere between roughly 20% and 78%, i.e. NOT EXACTLY AN ACCEPTABLE STANDARD DEVIATION, BECAUSE IT IS INCONCLUSIVE DATA AND ALL OVER THE MAP!
Interestingly, the highest number, i.e. 80%, being the WHO fluff, was only number cited in the original post!
Meanwhile, a WHO report found that “80% of infections are mild or asymptomatic, 15% are severe infections and 5% are critical infections”. Though we don’t know what proportion of that 80% were purely asymptomatic, or exactly how the cases were counted, it again points to a large majority of cases who are not going into hospital and being tested.