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LINK Fall Bivalent Boosters: Science Update Round 3 YLE 12/08/2022

By Katelyn Jetelina MPH PhD

Alright people, the data you’ve been waiting for: the first real-world effectiveness data on the fall COVID-19 (bivalent) booster. Here are the results.

Science until now
As a reminder, we hoped the fall booster would accomplish three things:

Greater protection against infection and transmission, by boosting our first line of defense—neutralizing antibodies;

Longer protection against infection and severe disease, even just by a few months; and

Broader protection, or the ability to create antibodies that “see” more virus parts and “attach” more strongly compared to the antibodies we have right now.

We have ~9 lab studies showing all three of these things are being accomplished (see my previous updates here and here.)

However, what happens in a lab doesn’t necessarily translate to the real world. This is because the lab is a controlled setting, and the real world interacts with genetics, environment, complex immunity, human behavior, etc. We always need to rely on both for the “true” picture.

Real-world data
Last Friday, the CDC published the first “real-world” data on effectiveness of bivalent boosters. Their main question: Does the fall booster (with the bivalent Omicron formula) provide additional protection against infection? They compared people who got the fall vaccine (bivalent vaccine) + 1 mRNA vaccine dose of the regular formula, 2 doses, 3 doses, or 4 doses to unvaccinated people.

Study depiction made by YLE
The scientists used pharmacy data—360,626 tests from September to November 2022—to compare how many people had a positive or negative test.

This is what they found:

The fall Omicron booster provided additional protection with previous vaccination compared to no vaccination:

Among 18-49 year olds, the fall booster was 42% effective against infection

50-64 year olds: 28% effective against infection

65+ year olds: 22% effective against infection

There was a similar additional benefit of the bivalent vaccine regardless of the number of previous doses received.

The more time between doses, the more protection.

Among those ages 65 and older, for example, effectiveness was 43% if they got their last mRNA dose more than 8 months ago, compared to 28% if they got their last dose 2 months ago.

In all, this study found that fall boosters are helpful against infection.

Real world studies are inherently flawed, especially in places like the U.S. where we don’t have a national health system (nor solid data infrastructure). It’s messy and imperfect but our reality. This study used pharmacy testing data. People who go to a pharmacy to get tested could certainly be different from those that don’t go to pharmacy to get tested (and use at home antigen tests or don’t test at all). But this is the best we have right now.

A few thoughts
These results make sense. Several lab studies have shown an increase in neutralizing antibodies after the fall booster. Of our immune tools, neutralizing antibodies act the fastest and stop the virus before it starts replicating in our cells. We had a hunch the vaccines would protect against infection. How long this protection lasts against infection is a key question; we are at the mercy of time.

Delay in boosting. More time between doses helps prime the immune system. We’ve seen this with other vaccines. In fact, this is why the U.K. officially recommends at least 12 weeks between doses since the beginning of the pandemic. If we get a booster earlier, we won’t “exhaust” or “overwhelm” our immune system, but by delaying we get the biggest bang for our buck. I still stick to my recommendations last month.

Some may be disappointed in these numbers. Vaccines are not 100% effective against infection. But protection against infection is an added benefit. I’m anxious to see data on the effectiveness against severe disease, which is the primary purpose of vaccines. We don’t have this data yet. It’s coming.

Vaccination (and previous infection) is not enough. If you do not want to get sick (miss work, possibility of long COVID, etc.), other measures, like masks, are necessary. Yes, still.

Bottom line
We have lab data for fall boosters. We have real world data. And what’s coming in looks good—not perfect, but good. We have lots of reason to believe they will work even better against severe disease, especially among those over 50 years old. Go get your fall booster. We are at the beginning of a wave.

Love, YLE

“Your Local Epidemiologist (YLE)” is written by Dr. Katelyn Jetelina, MPH PhD—an epidemiologist, data scientist, wife, and mom of two little girls. During the day she works at a nonpartisan health policy think tank and is a senior scientific consultant to a number of organizations, including the CDC. At night she writes this newsletter. Her main goal is to “translate” the ever-evolving public health science so that people will be well equipped to make evidence-based decisions. This newsletter is free thanks to the generous support of fellow YLE community members.

HippieChick58 9 Dec 8

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Just got my bivalent booster on Saturday. Just like all my other shots no side effects except for mild soreness on arm.


Thank you for these stats. One difference between real information is that when it comes from true studies mistakes and anomalies are included. With to all the naysayers (they know who they are) they refuse to admit they might be mistaken or their comments overblown.


What about kids under 5? They aren’t eligible for boosters. Is it because it isn’t necessary or we don’t know if it will be beneficial or what? As an aside, I feel like a quick way to pick out all the sociopaths in a given society is to recommend a vaccine and see who screeches about how they won't do it because they’re healthy/never get that illness/don’t give a shit etc, and says not one word about how they might spread that illness to someone who is vulnerable. There is a crowd who doesn’t give two shits about who they maim or kill. It's creepy af, honestly.


I got the fall booster. To hell with the mask.


I have had five vaccines and when they tell me to get the sixth, l will not hesitate. I used to get the 3 day flu almost yearly. About 15 years ago l started getting an annual flu shot and haven't had the flu since, except one year when the flu they were expecting was a little different than the one they had prepared the vaccine for. I was a little sick, no fever, for about a day. Vaccines may not keep you from getting the flu or virus, but they will keep you from ending up in the hospital or worse.


I am a bit disappointed that even by waiting more than 8 months the efficacy rate was below 50% for 65 and older folks. poo. Still, I'll call and find out when my last booster was.
Still wearing my mask to go shopping, fuck it if I'm the only one in the damn store with one on.


I have never gotten a flu vaccine shot of any kind. Last time I had the flu was in 2012. If I've had covid, I didn't know it. I had a scratchy cough for two weeks about a month ago, got tested after first week, result was negative. Apparently my immune system is strong enough that I don't need it. 😁😎👍

Said so many overconfident people who went on to die from COVID.

My older brother had exactly the same approach...he died of COVID this August.
But one of the maxims he touted (and it is a shame he didn't follow it himself) was "How many empty chambers does it take before you have a game of Russian roulette?" Obviously, no one but an idiot would risk their lives on a 1 in 6 chance but how about 1 in 100? or 1 in 1,000? Would you play that game? What kind of reward would want for not blowing your brains out?
It sounds like an odd question but it is one we all ask ourselves when we stop ourselves from doing dumb things like driving home after maybe one too many drinks or running a stop light. ie. The consequences of a wrong decision far outweigh any possible gain.
In the meantime, I sincerely hope that you maintain your winning streak and that all of the chambers come up empty.

@273kelvin @273kelvin Does the phrase "Correlation does not equal causation" sound familiar to you?

@Captain_Feelgood Of course it does, I have lost count of how many anti-vaxers I have tried to explain that to, regarding the autism child vaccination myth. But as the figures in the op clearly show, there is a statistically significant advantage in being vaccinated. Now you can read that and ignore it anyway, your choice. In the same way, I choose to smoke even though all the odds are against me. But my decision is made with the full knowledge of how harmful it is. Not looking for excuses or deriding the main body of medical science.
Like I said before, I am truly happy that you have remained lucky and I hope you continue to be so. But bear in mind the old gamblers' maxim. "The race does not always belong to the swift or to the strong. That's just where the smart money is"

@273kelvin Unfortunately the shots they're giving people are NOT actually a vaccine, by definition that is. [] These shots do NOT prevent the recipient from getting said disease. It may or may not make symptoms more tolerable for those at high risk, and perhaps even unnoticeable to the very healthy folks out there. It certainly does not prevent anyone from getting covid. And therein lies the rub, so to speak.

@Captain_Feelgood Well, that's not what I got from those figures but if you know better...


It defies standard protocol to push these ineffective products and allow them to be administered under an EUA with less than 50% efficacy.

'The scientists used pharmacy data—360,626 tests from September to November 2022—to compare how many people had a positive or negative test.

This is what they found:

The fall Omicron booster provided additional protection with previous vaccination compared to no vaccination:

Among 18-49 year olds, the fall booster was 42% effective against infection

50-64 year olds: 28% effective against infection

65+ year olds: 22% effective against infection

There was a similar additional benefit of the bivalent vaccine regardless of the number of previous doses received.'

BDair Level 8 Dec 8, 2022

Great! Because I had mine last Friday, was sick over the weekend, poorly the rest of the week and finally feel okay except for injection site soreness. I’d hate to go through that for nothing.


The only booster I have so far is my yearly flu shot. I had the flu really bad three times in my life. The last time was maybe 30 years ago. Is it luck or the flu shot? Keep in mind that Covid is a type of flu and it may be coming back this winter.

Not quite. People talk of stomach “flu” but there’s no such thing. That’s norovirus. Coronavirus and influenza are not the same. The viruses are quite different. COVID is typically much worse than flu. If one were unfortunate enough to contract bird flu, COVID is far milder than that. I know of people being hospitalized from this year’s flu so it’s no walk in the park.

The common cold is murkier as it can result from rhinoviruses or some milder types of coronavirus. SARS-CoV-2 has a ways to go before it becomes just a cold. Technically it’s not flu.

@Scott321 OK. At this point I have had Covid 19 and later when I'm back at work my corporation paid me $100 to get vaccinated. No problem here as I've been vaccinated my entire life, in school and in the military.

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