Source: Immunogenicity and protective efficacy of influenza vaccination
Claude Hannouna, Francoise Megas, James Piercy, Virus Research 103 (2004) 133–138.
The importance of this graph will be clear about five paragraphs down.
At this point, with the Phase III trials of coronavirus vaccines well underway, even if they don’t have enough “statistical power” to do the formal statistical test, our public health bureaucracy ought to have a fairly good indication of how things are shaping up.
I’ve been waiting for any US public health leader to start leaking information on the likely effectiveness of the coronavirus vaccines. Informally tossing some numbers out there, to get us prepped for the eventual formal announcement.
We just got our first indication today. And, although the CDC Director broke the news gently, and indirectly, and with spin, if you paid attention, the news was clearly not good.
Today, the Director of the CDC was reported as having said that the coronavirus vaccine — which he says will be available by the end of this year — may only be about 70% effective.
That’s reported on this news website.
Unfortunately, that’s not what he actually said. If you read what he actually said, he didn’t say effective. (Which should mean, prevents you from getting infected.) What he actually said was that it had 70% immunogenicity.
All that means is that the vaccine provoked the body into producing antibodies for 70% of the people vaccinated. All that tells us is that the vaccines he’s talking about is a complete dud 30% of the time. The extent to which it actually prevents infection in the remaining 70% is unknown.
The right way to interpret this is that whatever vaccine he’s talking about, it is definitely less than 70% effective. How much less is an interesting open question.
Return now to the graph at the top of the page. That shows the relationship between immunogenicity (production of antibodies, X-axis) and the (relative) rate of infection, for flu vaccine. (From one old study of flu vaccine.) As you move to the right along the X-axis, you have patients who generated higher levels of flu virus antibodies in response to vaccination. And the height of the bar (the Y-axis) shows the (relative) risk of infection. As you move to the right and the level of antibodies in the blood goes up, the likelihood of infection goes down.
But the point is, just because a person developed antibodies doesn’t mean that the flu vaccine provided protection. E.g., people in the second group above (marked 20 -30) definitely had “immunogenicity” — they have measurable levels of antibodies — but the vaccine was only about 67% effective.
So, take your 70% immunogenicity rate, for the COVID-19 vaccine, and reduce that by some as-yet-unknown percentage, to arrive at effectiveness. And the end result is that we could easily end up with a vaccine that is less effective than the seasonal flu vaccine, which is 60% effective in a good year.
Arguably the most ominous (or maybe hilarious, or maybe desperate) sign in today’s CDC announcement was that the CDC Director said something to the effect that masks may provide you with more protection from coronavirus than the vaccine. Complete with props. If that wasn’t grasping at straws and/or an act of desperation and/or a ham-handed attempt at spin, I don’t know what is.
Because what he basically said was, eh, maybe this is as good as it gets. As he held up a mask.
Ah, and for icing on the cake, the Administration’s Political Officer assigned to the briefing then vigorously defended the President’s right not to wear a mask, and any American’s right not to wear a mask. Just to remind us of what a total crap show our Federal government is. In case we’d forgotten that.
You may think I’m over-reacting. But a) I’ve had my ear to the ground, waiting for this announcement, and b) the maker of the US vaccine has never successfully produced a commercially-viable vaccine using this mRNA technique.
And c) I think I’m able to spot a clumsy attempt at misdirection when I see it. Instead of waving his hands, the Director of the CDC was waving a mask. But I think that in this case, that serves the same purpose.
What if this is as good as it gets? Needless to say, if less than two-thirds of US citizens are willing to take a vaccine that’s only 60% effective or so, there ain’t no way to get to herd immunity (70% immune) other than the old fashioned way. By culling the herd. It also means that if all the vaccines work this poorly, all the old people in the US remain at risk, as long as this remains in circulation.
What if this is as good as it gets? I need to let that sink in a bit before I write anything else.