If you compare the endpoint "severe illness"... 11 out of ~15000 ended up with severe illness on placebo, and 0 out of ~15000 ended up with severe illness in the treated group.
This corresponds to binomial 95% confidence intervals of (0.0004, 0.0013) and (0.0000, 0.0002). So it seems to prevent severe illness.
Whether it reduces the odds of severe illness IF YOU ARE INFECTED or purely reduces the odds of severe illness by preventing infection--- you're right, there's not nearly enough n to know.
This corresponds to binomial 95% confidence intervals of (0.0004, 0.0013) and (0.0000, 0.0002). So it seems to prevent severe illness.
Whether it reduces the odds of severe illness IF YOU ARE INFECTED or purely reduces the odds of severe illness by preventing infection--- you're right, there's not nearly enough n to know.