No doubt, that he appeared sick in the callroom, and given the developing story of norovirus outbreak on the hotel where Makwala was staying, do I believe the medics made the right call, if indeed Makwala showed the exact same clinical symptoms as other victims of the norovirus.
Normally, tests are not performed, as the results normally take longer time to aquire, than for the patient to get well, and the diagnosis is most often based on testimony of the patient, and the situation (other patients with same symptoms).
Given his ability to perform, is it unlikely (but not impossible), that he had the norovirus, but it's 20/20 hindsight to claim IAAF medical staff made the wrong call. If indeed he had the virus, would he be a liability to the athletes in warmup area and callrooms.
Any links to whether he was forced out of the 200, or withdrew voluntarily due to vomiting?