Covid-19: Oxford vaccine could be 59% effective against asymptomatic infections, analysis showsBMJ 2020; 371 doi: https://doi.org/10.1136/bmj.m4777 (Published 09 December 2020) Cite this as: BMJ 2020;371:m4777
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In 'normal' vaccines trials there is a 'challenge' phase when animals/candidates are given a vaccine and exposed to the virus to test its efficacy. I do not see how the Coronavirus vaccines have been subjected to any form of challenge. If not challenged, how are the efficacy results supported or substantiated?
If sample candidates wore masks, kept their distance and washed hands, per Government instructions, then how are they any more exposed / different from the general public abiding by those same guidelines?
On a second point, transmissibility of the latest variant, I have tried, as a layman, without success, to research why it is so much more transmissible compared with the the original variant. If wearing masks, keeping 2 metres distance and washing hands are constants applying to both variants, then why is the new variant more transmissible? Possibles could be the greater spread by children under 12 who do not wear masks, do not keep 2m from their peers and whose hand-washing may not be as hygienic as their parents, alternatively a super spreader event from a parcel or postal distribution point in SE England - a physical distribution, or smaller droplets that are not arrested by masks (unlikely), or the new variant lasts longer on surfaces that people touch before they wash their hands, or that 70% alcohol gels are not effective enough, or..... or....
On this subject, I raised this question with Chris Smith from Cambridge University on national radio and while there was a 'possible rationale', it was more technical / medical / academic than practical. The short answer is that the reason is not known. The latest tier 4 restrictions are not stopping the spread of the new variant, even within the tier 4 regions. In short, what does the common layman have to do to stop the transmissibility of the new variant? What extra steps are necessary?
Iain Pearson, Reading, UK
Competing interests: No competing interests