A Half Dose of Moderna Is More Effective Than a Full Dose of AstraZeneca | Hacker News Reader

A Half Dose of Moderna Is More Effective Than a Full Dose of AstraZeneca

marginalrevolution.com

34 pointselsewhen16 comments

That chart also says that half dose of AstraZeneca is more effective than a full does of AstraZeneca.

Doesn't change the conclusion that Partial Moderna is better, or the comments here pointing out potentially different use cases.

Just funny.

If you look at that graph, the sample size for half doze(44%) of AZ is too small: N=41 and N=62. I would not be picky over 5% difference. The trend overall looks solid to me. It's not the first time I hear that the efficacy rate of Sinovac is about 50% and the fact that Phizer and Moderna are the best options.

There are other studies on the effect of AZ half doses, because of the "Italian mistake" in GB, which was submitted to the European approval agency, so it became public knowledge. The sample size was over 3000, the effectiveness was over 95%.

Well, the Pfizer shot works doesn’t it? It’s extremely similar to Moderna and its standard dose is 30% of the Moderna dose.

Yeah, there's a few things suggesting that the Moderna dose should be about half what it actually is, but it was rushed to approval due to the Covid-19 emergency and I don't think the dosing got tweaked as much as it could've been.

IIRC they errored on the side of “let’s put in extra mRNA so if some degrades before administration there will still be enough left.”

It might be to blame for more intensely reported side effects.

The simple existence of the second mRNA doses is similar. Almost all vaccines do better with a booster. They didn't know whether they needed it or not, and it was an entirely new technique, so they went with a conservative choice.

In fact we know now that single-dose mRNA vaccines work at around 70% effectiveness, which is great. That's essentially the way they're being deployed in the UK and now Canada, people get one dose and then go back to the end of the line. And this is working extremely well, quite a bit better than the vaccination regime in the US, which is "wasting" all those early second doses on comparatively much less effective booster shots.

We have so many doses in the US now that it doesn’t really matter if we “wasted” them as early second doses. We now have doses sitting on the shelf expiring. We haven’t had lines for vaccines for over a month, and I’m in one of the highest demand locations in the US. US vaccinations peaked mid April, and the decline after that has been 100% due to demand.

Unfortunately, a single dose of the mRNA vaccines or any other vaccine seems to be pretty ineffective against the variant currently circulating in the UK - it really takes two doses, and there doesn't seem to be any way to change the rollout to give both doses sooner.

That’s not how drug development works at all as there are too many variables to just compare mass of the doses.

How much of each nano particle makes it into the cell?

How much actually get transcribed?

How much get excreted outside the cell?

How responsive is the immune system to each modified spike protein segment?

It’s like comparing lines of code - “oh this routine is 800 lines and the other is 500, so the 800 line one is more complex”.

The biggest question for me is whether this will hold up with variants, particularly delta. My understanding of the data from the UK is that the effectiveness of the full two-dose regimen against delta is quite good, but the single dose less so. There are a lot of unknowns here, but if there is greater chance of vaccine escape, we could be playing with fire.

But that half dose has to be stored in conditions much cooler than the AstraZeneca vaccine. Obviously there's a place for both but the portability of the AstraZeneca and J&J vaccines can't be understated.

The storage requirements for the Moderna and Pfizer shots are heavily on the safe side. They went with it for the EUA because there was simply no time to prove that it could be safely stored at normal temps. The overwhelming consensus, however, is that it can be. I suspect the full FDA approval will change the guidelines to allow normal refrigeration up to 30 days.

I saw a press release from the Singapore health authority that they have extended the time allowed for these vaccines to be stored in regular refrigeration. It doesn't sound unlikely that this time would be extended further until the requirement for ultra low temperatures is no longer needed?

https://www.hsa.gov.sg/announcements/press-release/pfizervac...

That's likely no longer true. The updated guidance for Pfizer (which originally had colder storage requirements than Moderna) is:

"undiluted, thawed Pfizer-BioNTech COVID-19 Vaccine vials to be stored in the refrigerator at 2°C to 8°C (35°F to 46°F) for up to 1 month. Previously, thawed, undiluted vaccine vials could be stored in the refrigerator for up to 5 days."

https://www.fda.gov/news-events/press-announcements/fda-brie...

From the chart:

Moderna evaluated in adults 18-55 (N=15)

AZ evaluated in adults 18-55 (N=41) and 56+ (N=62).

So yeah. Ok.

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