Posting here to try and catch the eyes and brains of scientists!
I have a lot of questions, so if you are only willing/able to field a few, I would be very grateful nonetheless!
So, I have been reading about the Pfizer and Oxford vaccines, and wondered whether anyone who can 'read' scientific papers can clarify.
The 'efficacy' statistic looks to be a big contrast at first glance...
However. I understand that a big difference in reported efficacy is that the Oxford trial asked all its volunteers to swab weekly, regardless of symptoms, so their data includes asymptomatic persons infected with Covid, which the Pfizer trial does not - the Pfizer trial only accounts for those presenting symptomatically. Can an estimate be made as to the updated Pfizer efficacy percentage if this data were to have been collected? (Or the Oxford percentage were the data to have been eliminated).
Are both vaccines 100% effective against severe illness and hospitalisation?
Are the much-touted efficacy statistics about preventing any symptoms, or rather, are they about preventing infection altogether, whether asymptomatic or symptomatic?
What is the data on what kind of protection a single dose confers - in terms of efficacy against severe illness and hospitalisation?
Did both studies use a good sample across groups, say, age groups etc? Are there any quibbles with how either trial was conducted or reported on?
Additionally, I understand that when the first dose was halved for the Oxford vaccine, efficacy shot to 90% - taking asymptomatic patients into account, does that now make it more effective than the mRNA vaccines? Does anyone know whether this has been implemented, and people now receiving the Oxford vaccine get an initial 'half' dose?
To add to my confusion, I found this quote on another mn thread that suggests it's not about dosage, but rather dosage intervals - does anyone know which it is? -
It turned out that the ‘half dose first’ regimen had a confounding variable; the length of time between doses. The ‘half dose’ group had gaps of between 3-26 weeks between their first and second dose. When they looked at the data they showed that a gap of 8-12 weeks gave 90% efficacy
Finally if there are any thoughts about the vaccine vectors in general, adenovirus 'vs' mRNA, more of a discussion than a 'vs'! Their historical and anticipated usages, etc.
Also whether a 12 week gap between Pfizer doses is likely to harm its efficacy.
And finally, whether vaccine efficacy re asymptomatic infection is an important piece of data to collect regarding potential spread of the virus, and whether the mRNA trials are doing this.