Retrospective 976 hospitalized patients with 834 treated with HC Q+AZ showing HC Q mortality relative risk RR 0.35, p < 0.0001. Note that in this case HC Q was recommended for mild/moderate cases, so more severe cases may not have received HC Q (which may also be why they became severe cases). We note that this is opposite to a common bias in HC Q studies - in many cases HC Q was more likely to be given to more severe cases.