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Sinovac's vaccine efficacy less than 60% in Brazil trial -report

130 points| drocer88 | 5 years ago |reuters.com | reply

52 comments

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[+] sudosysgen|5 years ago|reply
Can we please mention that this is not an official result?

Less than reputable brazilian news have come up with wildly different numbers, from 40% to 63.75% to 80%. This is incredibly unreliable.

How about not writing articles about rumors from Brazilian Yahoo News?

Least of all, reports that have been dismissed by the actual institute doing the trials.

[+] speeder|5 years ago|reply
I am Brazillian.

People are not trusting anything regarding this...

1. Instituto Butantã, claims they can't publish the results of the trial because of NDA with Sinovac, and won't comment about the effectiveness.

2. Meanwhile Sinovac is being tried for corruption in China, and their defense was actually confirm they paid bribes to officials in various countries to approve their vaccines (not Coronavirus ones, the trial is about 2011 stuff), but claim that the officials (including Instituto Butantã related officials) that used extortion, and thus they are victims, not perpetrators of the crime.

In this situation, when allegedly bribery is afoot, do you really think we should blindly trust the alleged criminals numbers?

[+] dmix|5 years ago|reply
Deleted
[+] ulfw|5 years ago|reply
So far we heard 91% (Turkey), <60% (Brazil), 78% against mild cases (Brazil), 65% (Indonesia). So... what is it really?
[+] dmix|5 years ago|reply
Turkey claimed 90%+ but the numbers in their tests were tiny:

> The Turkish trial data for CoronaVac is based on analysis of 1,322 participants which included 29 infected people, and efficacy evaluations were made 14 days after the second dose was administered.

Plus I’m not sure comparing countries at that level is a good base line. There could be major demographic (vitamin D which has been shown to play a role has also been shown to be less prevalent in darker skin) and even the details of the trials (Turkeys itself usinf relatively small samples). Or even the quality of the healthcare system treating these people after they get sick.

From the same article:

> Experts say it’s not unusual for a vaccine to show different efficacy rates in various settings, as trial protocols, data size and population could impact results, but the way CoronaVac data has been released created some confusion.

https://www.reuters.com/article/us-health-coronavirus-sinova...

This leads to the same conclusion that we need to wait for more and better data. But also recognize all data isn’t equal when we do get it.

[+] raverbashing|5 years ago|reply
Well, besides the numbers being hearsay, this refers to "full efficiency" which is pretty much a meaningless number in this case. It refers to the number of people who had any kind of symptom manifestation

Now do you care that instead of dying you got a runny nose? It's a useful number for statistic purposes, not practical ones

[+] cm2187|5 years ago|reply
You do if it is about whether it stops spreading the virus or not
[+] superkuh|5 years ago|reply
60% is pretty good for an inactivated full virus vaccine. That's about what the trivalent seasonal influenza vaccines (using the same general technique) achieve.
[+] gruez|5 years ago|reply
>That's about what the trivalent seasonal influenza vaccines (using the same general technique) achieve.

Doesn't the seasonal flu vaccine also have the issue that they have to "predict" what strains would be active? Is that already factored into the effectiveness rate?

[+] contravariant|5 years ago|reply
Perhaps, but the last time I checked you needed around 60% of the population to be immune in order to halt the pandemic, so I'm not sure if 60% is good enough in this case.
[+] dehrmann|5 years ago|reply
I'd still rather have an inactivated virus vaccine over an mRNA one because the technology has such a long track record.
[+] ulfw|5 years ago|reply
Why the constant "flu" comparisons? It's a different virus.
[+] xeromal|5 years ago|reply
Does anyone know if you keep giving the vaccine to the person after it fails, its effectiveness could eventually trend up to 90+%?
[+] JonoW|5 years ago|reply
Yeah not sure why this is downvoted, seems a fair question.
[+] kolinko|5 years ago|reply
It might work the other way - the immune system may get used to a given virus and begin ignoring it.

This is the way anti-allergy therapies work - you inject patients with a progressively higher amounts of the substance the person is used to and the immune system stops responding to it.

With vaccines, there have been cases of this effect (found during testing, and not with covid vaccines so far).

[+] dehrmann|5 years ago|reply
Not sure why you're being downvoted. We give multi-dose vaccinations all the time.
[+] bluenose69|5 years ago|reply
The first sentence of the article ends with "citing two people who seen the results." How does such a glaring grammatical error get past Reuters editors?
[+] roel_v|5 years ago|reply
Does anyone know of a good resource that explains what 'efficacy' means for a vaccine, and what can (and cannot) be extrapolated from it? The reported efficacies are (from what I understand) 1 - (n infections in experimental group / n infections in control group). But then I see people draw wildly varying conclusiona from that, most of which I suspect are wrong (e.g. the relationship between 'efficacy rate' and 'group immunity' after everyone is vaccinated). But despite looking long and hard, I can't anyone explaining in detail what such efficacy rates mean (and don't mean).
[+] tallanvor|5 years ago|reply
I may screw this up, but efficacy describes how effective the vaccine was in the trial vs the control group. So if each group had an equal number of people, and 100 people in the control group got sick, but only 5 people who received the vaccine group got sick, the efficacy rate would be 95%.

The hope, of course, is that the vaccine's effectiveness (how well it does at preventing covid) is close to the efficacy, but it's very hard to know for sure. That's why it's best to have the trials spread out among demographics and even locations, to better try and identify what may cause the vaccine to be more or less effective.

[+] radu_floricica|5 years ago|reply
Very good point. I read recently that there were no hospitalizations in the AstraZeneca vaccinated group, so by this metric it's 100% efficient. I really want to hear those numbers as well, it makes a huge difference in the decision to promote a certain vaccine.
[+] threeseed|5 years ago|reply
Sounds like these countries are better off waiting for the AstreZeneca vaccine.

Which is affordable and far more effective.

[+] votepaunchy|5 years ago|reply
AstreZeneca showed 70% efficacy in the general population. Does this qualify as “far more effective” when the mRNA vaccines showed 95% efficacy?
[+] xbmcuser|5 years ago|reply
Is this for the 1st shot only before the booster is administered as if recall correctly for the other vaccines it was around 75-80% for the first shot and went to 95%+ after the 2nd shot. Even if it reaches 75-80% after the 2nd shot it is actually good enough and that was the figure most of the medical professionals were hoping and expecting before the 90-95% effective vaccines came out.
[+] sanxiyn|5 years ago|reply
This is after two shots.