That's accurate. It was a known concern going into the trials. Enough so that the Russian Sputnik V vaccine purposely used a different adenovirus in the first d

That's accurate. It was a known concern going into the trials. Enough so that the Russian Sputnik V vaccine purposely used a different adenovirus in the first dose and the second dose and appears to have about 92% efficacy rate. I believe Oxford is also planning on running a trial using a mix of the Oxford and Spuknik vaccines to see if it improves efficacy.