Hallucigenia wrote:ursaminortaur wrote:Wouldn't it then be an idea to combine a delta and classic vaccine in a single jab just as the yearly influenza jab consists of a number of different flu variant vaccines ?
It's a possibility, but from a manufacturing and regulatory point of view, there's a lot to be said for keeping things simple, and the classic vaccine still works pretty well against delta. Given the timescales, I suspect most of the world will end up getting a classic jab - once trials of the delta vaccines as single shots are complete we will understand better how well they work in their own right, and then there would need to be separate trials of a mix. And then an assessment of whether the additional complexity was worth it relative to the variant mix at the time.
I know what you meant but being a bit picky I could extend that further. If a booster dose is taken into consideration I would actually strengthen your comment to "the classic vaccine still works exceptionally well against delta". At least on the basis of Israeli studies their Pfizer booster program seems to deliver 10 to 20 fold increases in efficacy against 6 month old double-jab residual efficacy that, even with the slightly trickier Delta variant now prevalent which I assume is the dominant variant that people in that Israeli booster trial are exposed to at the moment. The results from that trial so far show the booster increasing efficacy against symptomatic disease by about 11 fold so, even if un-boosted protection against Delta has waned in some recipients down to close to 50%, that still gets it back up into the 95+% range and against severe disease the booster effect observed was even more dramatic with a 19.5 fold increase so protection back to the >99% mark I think (those increases have confidence intervals associated with them of course). [ Source: https://www.nejm.org/doi/full/10.1056/NEJMoa2114255 ]
Some cause for optimism I think. Under current UK policy I become eligible for my booster shot in 25 days time and I will be booking my booster as soon as I possibly can.
- Julian