You claim zero. But the article links to the following studies: https://jamanetwork.com/journals/jama/fullarticle/2768351, https://www.clinicalmicrobiologyandinfection.com/article/S11..., https://n.neurology.org/content/early/2020/08/10/WNL.0000000..., https://www.bmj.com/content/370/bmj.m3026, and https://www.cdc.gov/mmwr/volumes/69/wr/mm6930e1.htm?s_cid=mm.... Google also turns up https://www.nature.com/articles/d41586-020-02598-6.

That doesn't seem like "zero" to me.

Furthermore note that the result wouldn't be surprising. Long-term followup on SARS finds that 15 years after being infected, 4.6% still had visible lesions in the lungs and 38% had reduced diffusion capacity. Given that, the claim that a significant minority (eg > 5%) of people with COVID-19 should still have significant symptoms after several months seems quite plausible.