I think you're right, now that I know what to look for. The AZ/Oxford vaccine has lower symptomatic efficacy than the mRNA ones, and it's asymptomatic efficacy

I think you're right, now that I know what to look for. The AZ/Oxford vaccine has lower symptomatic efficacy than the mRNA ones, and it's asymptomatic efficacy is lower still. We don't know what the asymptomatic efficacy of the mRNA vaccines is yet, but since their symptomatic efficacy is higher, it would be reasonable to expect their asymptomatic efficacy to also be higher. So at the end of the day, the main question regarding the AZ/Oxford vaccine is whether a half-dose starter shot regimen, or longer time between doses can bring its efficacy more consistently up around 90%, which would make it only slightly less effective than the mRNA ones, or if it's efficacy is actually just lower.