From the medpagetoday.com link:
"... there were no cases of hospitalization due to severe COVID-19 in either group, but because of participants' demographic and clinical profile, "the trial findings are inconclusive" with regards to whether or not the vaccine protects against severe disease from the B.1.351 variant.
Exploratory analyses found about 33.5% efficacy (95% CI -13.4 to 61.7) against COVID-19 of any severity more than 14 days after the first dose."
Meanwhile from Canada (Dr. Sumon Chakrabarti, an infectious disease specialist in Mississauga, Ont.) comes: "When you look at deaths and hospitalization, it doesn’t matter if it was Johnson & Johnson, AstraZeneca, Pfizer or Moderna, it was freaking amazing,” Chakrabarti said. “Thousands of participants in the treatment arm of the trials, and not a single person died, not a single person was hospitalized.”
It seems that the picture is not clear. I believe that AZ's measure of 'cases' in their trials was a positive test, regardless of symptoms, while Pfizer just tested symptomatic patients. The Canadians say that "Pfizer and Moderna [were] testing its product when the COVID burden was relatively lower in parts of the world. Johnson & Johnson and AstraZeneca, meanwhile, had their trials later when circulation was increasing, and more transmissible variants were spreading at a rapid pace."
It's so hard to draw any definite conclusions. Personally, I would say that the vaccine in the arm is better than any vaccine (however superior it may appear) in a bottle. It's also the case that scientists are working busily at preparing boosters should they be needed against particular variants.