By using antibody levels to measure vaccine efficacy, a team of researchers was able to estimate how good fractional doses of various vaccines are. Here are the results:
A half dose of the Pfizer vaccine has an efficacy of about 80%, which is still better than a full dose of the J&J or AstraZeneca vaccines. But the big winner is the Moderna vaccine, which displays nearly its full efficacy even at a quarter dosage.
It's too late for this to make much difference in the US or Europe, but we're going to need billions of doses of vaccine to protect the rest of the world. If the Moderna vaccine can be stretched 4x, it can protect a whole lot more people. Combined with news that the Moderna vaccine can be transported using standard refrigeration, it has the potential to be a significant factor in vaccinating Africa and Asia over the next year if production can be ramped up.
Yes, for the many countries that have little vaccine available to them, this could save literally millions of lives. There are some logistical issues: to get these reduced doses may require a different kind of syringe to be available. But it's really one of the most positive developments on the Covid front since the development of the vaccines themselves.
It's not at all surprising that Moderna retained more effectiveness in smaller doses than Pfizer, since the standard Moderna dose is roughly 3x that of Pfizer (100 vs. 30 micrograms of the active ingredient). A quarter dose of Moderna is not all that much less vaccine than a standard dose of Pfizer.
Moderna was, for whatever reason, very cautious in their initial dosing studies. Hopefully studies like this will let the available supply stretch much further.
I was coming to make this exact point. I think that there is an expectation in the field that this will also account for differences in side effect prevalence when those data come available.
I think it is worth clarifying that "team of researchers" refers to "a team of economists", and that the article is a self-published working paper (as is standard in the field economics).
The idea is plausible and worth exploring but I would be a lot more confident if this team had at least some immunologists or relevant subject-matter experts.
The paper just aggregates the results from late-phase tests of the individual vaccines, and those data were presumably produced by subject-matter experts. This paper is about as reliable as the test results themselves.
Please be careful interpreting this data. It does not apply to the B.1.617.2 variant that's tearing its way through India and the UK. Delta seems to have partially escaped the first dose protection from the Pfizer and Moderna vaccines.
It's also important in this discussion to separate dose size and partial dose patterns (1 or 2 shots from a 2 shot protocol).
I looked it up--the studies followed the one or two dose regimen as recommended.
What I couldn't find out is weather the partial doses were because of smaller injection sizes, probable, or if they made up more dilute batches. In the later case, the injection volume would be the same, as could be the concentration of adjuvant. It would just be the the active ingredient, e.g. the mRNA component, that had the lower concentration.
Myocarditis is a newly discovered side effect of the Pfizer vaccine. Oh well, it was good while it lasted. You’re all on you’re own now. Good luck.
Also Covid-19. Roll your die.
https://www.cnn.com/2021/06/09/health/myocarditis-covid-vaccination-link-clearer/index.html
Possibly with Moderna too, and mainly with young men. Would expect lower dosing to help. Reports on young (men) have it at less than 10 in a million, and recover fairly quickly with treatment. If that rate held for everyone, then see ca. 4000 hospitalizations total for entire US population, which is a little more than the number of people currently hospitalized with Covid today.
As we learn more, vaccination strategies can change so expected side effects can be minimized.
This isn't terribly novel. The data's been sitting in Moderna/Pfizer Phase-II results since nearly one year ago, showing the efficacy rates between dosages and shots.
Also, why hasn't anyone LOL'd at China's Sinovac's 51% efficacy and how they spent half a year knocking down Moderna/Pfizer/J&J/AstraZeneca, only to have recently admitted that it might have to "combine" their vaccine with one of the western vaccines?
Yea, not so much.
The reason the new Delta variant is now tearing through the UK is because they did employ the "single dose to cover more people" strategy, and Pfizer for example is only 33% effective with one dose against Delta. It goes up to 88% effective vs Delta with both doses.
Though the UK is also using the Astra-Zeneca vaccine (ca. 50%).
However this study focused on dosage levels, not number of doses--so followed the recommended number of doses and timing.
We don't know, for example, if a two dose J&J vaccine would be better than a single dose that is twice as large, the latter being done in this study. It also did not look at mixed dosing which some studies suggest might be better.
First dose first strategy is not that bad, as long as you do the follow up dosing. But your right, that also has to be re-evaluated against variants and response of given vaccine to said variants.
in SE Asia, China has already stepped in as Savior of the Country in Cambodia, Vietnam is handling itself, Thailand could certainly use some immediate help, as well as Malaysia and Indonesia. Philippines, like Brazil, has such unstable leadership that it's just as likely to be sold by their president for profit as given to the population.
The good news is that the Moderna vaccine is also generic since the US government picked up all of the R&D costs as well as all of the costs of the basic research for mRNA vaccines. Oh wait, it's not because in the US we socialize the risks and privatize the profits. that's the "free market" at work.