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Comment by ehsankia | Hacker News Reader

Right, unless you do a full trial with all vaccines side by side with similar sample/timeline, it's not really possible to tell. Also, the error bar on these effectiveness numbers are realistically probably +/- 5% or more, so it's not like a 76% is definitely worse than the 80%.

The dosage also matters. J&J for example decided to study one dose first, but are now doing a phase trial to see how good the immunity is for a 2-dose program. So potentially if you get a second dose (maybe down the line), you will also get a stronger immunity closer to the other 2 dose vaccines.

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> Also, the error bar on these effectiveness numbers are realistically probably +/- 5% or more, so it's not like a 76% is definitely worse than the 80%.

But we're talking 91% vs. 76%.

You can't compare the 91% vs 76% numbers because the 91% test was performed in the late summer last year between virus waves and in a location with an less-contagious form of the virus.

Whereas the JJ virus was tested during the fall 2nd-wave in South Africa when there was a lot of cases and more cases of a higher infection strain.

The only fair comparison would be if all of the testing was done at the same time in the same geographic location.

source: https://www.youtube.com/watch?v=K3odScka55A&feature=youtu.be

There was a new, recent study that showed that the mRNA vaccines were still 90% effective among healthcare workers during the big surge in December/January period when the variants were certainly present.[1] This doesn't mean the J&J vaccine is bad by any means, but it does show how incredible the new mRNA vaccines have performed.

[1] https://www.statnews.com/2021/03/29/real-world-study-by-cdc-...

From that same study:

> The study suggested that even the first dose of vaccine was 80% effective at preventing infection

Which is within the error bar of J&J's one dose result in the US (75%). We will have to see the results of the 2-dose J&J trial coming out soon, but I expect that to be around 90% too.

It's also worth noting that some places in the world (UK, Canada), have been using 1-dose pfizer regimen to get the most out of their short supply, with possible 2nd shot 3-4 months down the line. Similarly, we could see a delayed J&J booster being given to increase immunity to matching 90%.

No, the 91% from Pfizer is just announced and covers roughtly 6 months, including up until at least the middle of march, at which time the variants were circulating. Notably this covers the entire time of the J&J trials.

Of course they used somewhat different geographical regions so you can't compare them, but still the 91% does include variants.

Right, but as the comment above was pointing out, there are many other factors.

Pfizer/Moderena both did their trial from July-November, whereas J&J did their phase 3 from Sept-January. Looking at the COVID case graph [0], you can see J&J was tested at the peak. Not only that, J&J was party tested in the UK and South Africa, when the two new variants were starting to take over.

[0] https://media.npr.org/assets/img/2021/02/15/seamus-coronavir...

Just this week we also saw data from Pfizer & Moderna mRNA vaccine rollouts to frontline healthcare workers in December (at a time of peak infection and emerging variants) that touted 80% effectiveness after a single dose, 90% after two doses. I'm struggling to find a reason not to interpret that as further evidence that the mRNA vaccines are in fact more effective than the J&J shot.

Medical workers take precautions better than the general public, maybe? But they're also far more exposed.

80% with one dose seems right in line with 75% with one dose of J&J (in the US). For what it's worth, J&J is also now doing a phase trial of two doses, and I expect that to be around 90% too.

So yes, once you take into account the +/- 5% error, they seem to be pretty much equal.

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