There are two potential skews I can see in that study. The higher percentages of asymptomatic and URTI with control patients may mean they had less time on infection and the body had not ramped up a fuller immune response. The second is that 3 patients were pulled because of worsening symptoms, 1 died and 1 PCR positive left because of side effects,
Even with the skew those seem to be statistically significant results. Awaiting results from larger studies.