Is the Novavax vaccine safer than Pfizer? It doesn’t seem so.
The Novavax vaccine is now approved as a booster. Here’s what the data has to say on safety.
Many critics of the Pfizer vaccine call it “experimental gene therapy”.
Pfizer and Moderna both use messenger RNA to instruct your cells to make covid’s spike protein. This was a new technology that was researched for years, but never before approved for use.
This summer, a different type of vaccine got approved. Novavax can not be described as gene therapy. There’s no RNA or DNA involved. Instead of using RNA to instruct your cells to create the spike protein, the Novavax vaccine simply injects a small amount of the spike protein.
Both train your body to create antibodies against covid, but Novavax is simpler. It could possibly be safer, because it skips the RNA step. It could also be more predictable. With RNA vaccines, it’s hard to know exactly how much of the spike protein cells will produce. With Novavax, you know exactly how much spike protein is injected.
There was some hope that it could be used around the world, because Novavax doesn’t need to be frozen at cold temperatures. It can be kept in a normal fridge.
There was also some hope that vaccine-hesitant people would get this shot, since it’s more like a conventional flu vaccine.
It was promoted by many of the most famous covid vaccine critics.
Robert Malone promoted it as better than the mRNA vaccines.
Peter McCullough said it would be a safer vaccine.
Steve Kirsch was certain that Novavax is the safest vaccine.
More mainstream voices, like Dr Drew, also recommended Novavax.
So, Novavax has now been approved for a few months. It has more recently been approved as a booster shot.
Is it proving to be safer than the Pfizer and Moderna vaccines?
Did any vaccine-hesitant people actually get it?
Is Novavax a safer vaccine?
The short answer is “no”.
Surprisingly, Novavax can also cause myocarditis in young men. The data we have suggests that this happens 10 times as often with Novavax as it does with Pfizer.
The conspiracy theorists thought Novavax would be safer because it’s not “gene therapy”, it uses a simpler technology. But the world isn’t always that predictable. We actually have to do experiments, ask questions, and collect data to understand how it works.
The data comes from two Novavax trials, in the US and the UK. The US trial had about 30,000 participants. 20,000 were given the vaccine, the other 10,000 got a placebo shot.
The good news is that the shot was highly effective — about 90% against preventing people from getting covid.
10 people in the trial developed moderate or severe covid symptoms. All were in the placebo group. As far as the trial data is concerned, Novavax is 100% effective against severe covid symptoms.
The trial happened between December 2020 and April 2021, so this was against the alpha variant. Like other vaccines, the efficacy likely went down a little against Delta and a lot against Omicron. Novavax is currently studying an updated vaccine for Omicron.
The bad news is that it still causes myocarditis.
There were 6 cases of myocarditis or pericarditis seen in the vaccine group, and only 1 in the placebo group.
The FDA offers this summary of all the cases:
Four of the six cases that happened with the vaccine look clearly related to the shot — most happened 2–3 days after the 2nd or 3rd dose. One happened 8 days later. There was no other explanation for the illness.
A 5th case happened 10 days after the shot. The patient also had strep throat. It’s not as obvious if the vaccine is related.
The 6th case happened 28 days after the first Novavax shot, after the patient got covid and kidney damage. Myocarditis was more likely caused by covid than by the vaccine.
Seeing myocarditis with Novavax is interesting, for two reasons.
First, it calls into question many of the theories for why vaccines cause myocarditis. Conspiracy theorists suggest that the Pfizer inflamed the heart because it was “gene therapy”. Novavax does not use RNA, so that must not have been the issue.
Second, the rate that myocarditis showed up is actually higher for Novavax than Pfizer.
The cases above are combined from the US and UK trials. In total, there were 45,000 people vaccinated and maybe 4 or 5 cases of myocarditis caused by the vaccine.
That puts the odds around 1 in 10,000.
The NIH said the risk of myocarditis is 1 in 50,000 for the mRNA vaccines.
That would make Novavax about 5 times more dangerous.
To get the exact odds, we’d need to break it down by age.
The CDC gives these odds, for different age groups:
The myocarditis side effect mostly hits men in their teens and 20’s.
Men aged 16–17 are at the highest risk.
The odds of myocarditis are 1 in 14,000, for that age group.
The Novavax trial doesn’t give the odds by age group, but we can take a good guess from the data they do give us.
We know there were 2,248 kids aged 12–18 in the trial. Half were boys.
One 16-year-old was hospitalized with myocarditis.
The odds are around 1 in 1,100.
That suggests the shot is about 13 times more dangerous than Pfizer, for teenage boys.
We don’t know the exact number of men aged 18–24, but it looks like it was probably somewhere around 2,500.
There were 2 myocarditis cases in that age range.
That’s a rate of 1 in 1,200
That would be 22 times more dangerous than Pfizer, for young men.
We might get different numbers from monitoring, over time, after the shot gets rolled out.
But the data we have, so far, suggests the shot is not the best choice for young men.
The risk vs. reward might still be good for women and older men.
Is it possible that the risks were understated, for Pfizer and Moderna?
There were no cases of myocarditis seen in the Pfizer and Moderna trials. That supports the idea that both of those shots were safer. It has to be a rare effect if none of the 20,000 people in the trial got it.
It’s unlikely that these events were simply missed. Of the 6 myocarditis cases seen in the Novavax trial, 5 were hospitalized for a few days. These were significant health events that would be noticed and recorded.
It is maybe possible that these events happened and weren’t reported by Pfizer or Moderna.
But, several countries have since tracked the myocarditis problem and all found it was rare. It’s possible for one company to censor its trial data, but it’s very hard to have countries work together to hide a problem. It’s quite possible that the problem is rare enough that it didn’t show up in the trials.
The numbers each country came up with were a bit different.
The US said the risk was 1 in 14,000 for men aged 16–17, or 1 in 27,000 for men aged 18–24.
A study in Israel said it was higher, 1 in 6,600 for men aged 16–19.
A study in Italy said the odds were lower for young men, only 1 in 50,000.
So, if we compare to the CDC data, Novavax is 13 times as dangerous as Pfizer, for teenage boys.
If we use the Israeli data, Novavax is only 6 times as dangerous as Pfizer.
Either way, it looks like young men should avoid both Novavax and Moderna. There are safer choices, like Pfizer, Johnson and Johnson, or AstraZeneca.
Older people that want a strong boost to immunity might still want to consider Novavax or Moderna.
What causes myocarditis?
Since myocarditis happens with both Novavax and the mRNA vaccines, we can confidently say that it doesn’t happen because of “gene therapy”.
What actually causes it?
I’ll go over 2 theories.
Let’s start with a favorite theory among vaccine skeptics: myocarditis happens when a vaccine is accidentally injected into a vein.
This is unlikely to happen, there are no major blood vessels near where we inject it in the shoulder.
But still, maybe it does happen for some people. Maybe the shot is misplaced or enough of it leaks into the bloodstream, for some people, to cause a response.
In one video, vaccine-injured mountain biker Kyle Warner claims that he could “taste saline” immediately after getting his covid shot.
I’m skeptical about believing stuff I hear on Youtube, but let’s take Kyle at his word. Maybe that was why he got myocarditis.
There was one study done in mice, testing what happens if the Pfizer vaccine is injected intravenously. They used large quantities of the vaccine, about 70 times the human dose, and injected it directly into a vein.
That caused noticeable heart damage in the mice.
So, the theory is that if some amount of the Pfizer vaccine entered the bloodstream after intramuscular injection, it might be able to cause some heart damage.
The study’s authors identify one mechanism for why this would happen. Heart muscle cells have small tubes, called T tubules. The lipid nanoparticles in the Pfizer vaccine are small enough that they could enter these tubes. The authors explain:
“Smaller mRNA-vaccine lipid-nanoparticles (100nm diameter) can be sucked into larger T tubules (diameter >200 nm) of cardiomyocytes during diastole, but not into T tubules of skeletal myocyte (diameter 20–40 nm). Thus, the T tubule system of cardiomyocytes may concentrate mRNA vaccine lipid-nanoparticles like a sponge.”
So, the muscle cells in the heart collect the nanoparticles, the heart cells absorb the RNA, and express the spike protein. Maybe this damages them directly, maybe the immune system attacks them to cause inflammation.
Novavax also uses nanoparticles.
Pfizer uses small, lipid nanoparticles to contain the RNA. That prevents the RNA from breaking down, as soon as it gets into the bloodstream. It also allows the RNA to get into cells — these small fatty particles merge with the cell’s membrane, allowing the RNA to release inside.
Novavax also uses nanoparticles. These don’t contain any RNA, nor are they smooth lipid particles. They’re actually spiky little balls that look kind of like the covid virus:
They aren’t much like Pfizer’s nanoparticles, but the size is similar. With Novavax, the nanoparticles are 50 nanometers across, half as large as Pfizer. They’re still in the range where they would fit in a cardiac muscle cell tubule but not affect any other muscle cell. It’s possible they could still get concentrated there.
Since there’s no RNA in these shots, you’d have to think that the RNA is not the issue. Maybe the spike protein itself can cause damage to the heart cells? Maybe whatever the nanoparticles are made of is harmful to these cells? That seems unlikely, because they’re just fatty molecules. Eating a fatty meal doesn’t give you myocarditis.
The exact mechanism isn’t clear.
Actually, it’s not clear if anything about this theory is true. There’s a competing theory that might make more sense. We’ll get to that in a minute.
It would be great if the IV injection theory was true. Then the solution is simple. A nurse administering the vaccine would insert the needle, pull back the plunger slightly to check there’s no blood, and then inject it fully. Then, young men can get their covid shots and not worry about this risk.
It would be pretty easy to test the theory, though you’d need tens of thousands of people in the trial, because the reaction is fairly rare.
Maybe it would be easier to just give one state new guidance for how to do injections and then monitor the results at a population level.
If this theory were true, it might even be possible to redesign the vaccine to be safer.
Another study on mice suggests that using larger lipid nanoparticles are still effective at triggering an immune response.
This study found that the smallest particles were least effective, and 100 nanometers were the most effective. 200 nanometers weren’t the best size, but it still worked.
If 200 nanometers is some kind of threshold size, based on the diameter of the tubules in cardiac muscle, making them slightly larger than 200 nanometers could maybe prevent this side effect.
Myocarditis might be an autoimmune reaction:
The IV injection theory for myocarditis is popular because it’s easy to understand and it’s interesting to discuss.
But that doesn’t mean it’s true. Just like the “gene therapy” claims, this might be going in entirely the wrong direction.
A better theory says that myocarditis is an autoimmune response that some people get.
That study on mice didn’t find any difference between male and female mice, both got similar heart damage with an IV injection.
That doesn’t match the real-world experience with vaccines, where the problem is worse in men than women.
The IV injection theory fails to explain both the age and gender skew for myocarditis. Everyone has veins, so everyone would be at some risk of an accidental IV injection. Why is it mostly teenage men who get myocarditis?
Some people have suggested it’s because young men are more muscular. That seems unlikely to me — it’s hitting 16–17-year-old men harder than anyone else. The average man builds muscle well into adulthood. Many teenagers have too fast of metabolism to gain weight or muscle mass. If this was about muscle mass, it would hit men aged maybe 20–40.
The theory also fails to explain why most myocarditis cases happen after the 2nd shot.
The odds that an injection would hit a vein are the same, for the first and second shots.
Another problem is that we’ve measured the bio-distribution of the Pfizer vaccine. Some got out of the injection site and were found elsewhere. But it mostly ended up in the liver, it did not concentrate in the heart, as the “T tubules sponge” theory suggested.
A better theory is myocarditis is an autoimmune reaction.
Exposure to the covid spike protein makes antibodies. A paper from 2020 found that these antibodies can attack similar proteins in your own body. They found a reaction with myocardial α-myosin heavy chain proteins in the heart.
A more recent paper did cardiac biopsies of men who’d had vaccine myocarditis and found they all had a particular kind of antibody that other people did not.
In this case, the problem is that exposure to covid’s spike protein can always cause myocarditis for some people. The exact risk is higher for young people because their immune systems are stronger.
Both vaccine and virus can cause the same response. One study from Israel found that men are also more likely than women to get myocarditis from covid. So, this probably isn’t about men’s shoulder musculature. It has something to do with their hormones or their immune systems. It may be higher for men because testosterone increases inflammation and also causes a stronger T-cell response.
If this theory is true, then aspirating the vaccine needle won’t help. The protein injected into the shoulder will still cause a systemic immune response that reaches the heart.
So, in this theory, there’s a simple reason why one vaccine has worse side effects than another:
A stronger vaccine gives a better response against covid, but also a higher chance of myocarditis.
It looks like Novavax is the strongest vaccine, followed by Moderna, followed by Pfizer. AstraZeneca and Johnson and Johnson come in last, and are probably about equal, since they use the same technology and dosage.
Men under 40 should choose a weaker shot. Other people might want one of the stronger vaccines, for more protection against covid.
Getting the Pfizer vaccine is a bit safer than getting covid, for young men. But both Moderna and Novavax are likely to be more dangerous than covid, for young men, in terms of myocarditis risk.
What about younger kids?
For kids under 12, the Pfizer vaccine didn’t cause much myocarditis.
For boys aged 5–11 years old, the odds of myocarditis are 1 in 250,000. For girls, it was 1 in 500,000.
There may be something different about children’s hormones and immune systems.
But the Pfizer vaccine given out to children also used a smaller dose: 3 times less than what was given out to those aged 12 and up.
It’s possible we should have been giving young men a smaller dose of Pfizer, all along. And it’s possible that Novavax picked a dose that’s too large for young men.
Novavax is still conducting its own trial on kids younger than 12, so we have no data, yet. It looks like they will use the adult-size dose for children.
It’s possible that the trial will still turn out okay, maybe kids just have different immune systems so they don’t get myocarditis. But it may also show that the dose is too high for those kids.
Other side effects:
Other than myocarditis in young men, the Novavax vaccine might cause a few other rare problems.
There were 9 strokes in the trial group, and 2 in the placebo group. Remember, there were half as many people in the placebo group, so it’s more like comparing 9 to 4.
It’s less obvious that the vaccine is causing these events. With myocarditis, it’s consistently happening 2–3 days after the shot. The strokes happened over time, between 11 and 84 days after the shot. They didn’t happen to healthy young people, they mostly happened to elderly people with comorbidities. Only one of the strokes was fatal (in a 75-year-old woman).
With numbers this small, it’s possible for one group to randomly have more events than another. But there were more events in the trial group, and other covid vaccines were observed to have a small risk of blood clots or strokes, so it’s plausible that Novavax is also causing this.
If the 5 extra strokes were caused by the vaccine, that puts the odds around 1 in 4,000. That’s much higher than the known risk for the Pfizer vaccine, which is about 1 in 50,000.
Novavax also seems like it might cause clotting. 7 people in the trial had clotting events within 3 weeks of a shot. Only 1 person in the (smaller) placebo group did.
Also, odds around 1 in 4,000.
There were 8 cases of atrial fibrillation in the vaccine group and 2 in the (smaller) placebo group.
Odds 1 in 5,000.
And there was 1 case of Guillain-Barré Syndrome in the Novavax vaccine group and none in the placebo group.
Odds 1 in 20,000.
The vaccine trial probably didn’t kill anyone. There were 11 deaths in the trial group, and 5 in the control group. If the deaths were random, it should be 10 and 5.
Of the 11 deaths in the vaccine group:
• 1 died from a gunshot wound to the head
• 2 overdosed on drugs
• 1 had septic shock after pneumonia
• a 75-year-old woman had a stroke, 48 days after her second shot.
• a 79-year-old woman had a heart attack, 64 days after her second shot.
• There were 5 other heart attacks, aged between 39 and 66 years old. 4 had co-morbidities as well as histories of substance abuse (including cocaine, meth, and alcohol). The 5th was a suspected drug overdose.
That’s 6 heart attacks in total. There were 3 heart attacks in the control group, which was half as large.
To recap, the biggest risks are:
1 in 1,000 chance of myocarditis, for young men.
1 in 4,000 chance of stroke, for older people.
Is it safe?
The risk of a stroke from covid is about 1 in 2,200. So covid is twice as likely to give you a stroke as the shot is. And the shot gives nearly 100% protection against many of the other bad effects of covid, like dying from covid pneumonia.
It’s safer than getting covid.
But the rate of side effects is higher than other shots.
It’s not known yet which will work better as a booster shot. The latest experiments suggest that Pfizer’s bivalent booster probably won’t keep you from getting covid this winter, but it should reduce the severity of the disease. It’s possible that Novavax could work better as a booster. My guess is that it also won’t work well this year, because the shot is designed for the original covid strain seen in 2020.
Novavax is still working on a shot that’s been updated for Omicron, that one might provide better protection. So far, they’ve struggled to manufacture as quickly as Pfizer and Moderna. That begs the question of whether they’ll be able to update it quickly enough, for new covid strains.
Did any vaccine-hesitant people get the Novavax shot?
It’s been recommended by many mRNA vaccine skeptics, like Malone, Kirsch, and McCullough.
But very few people have actually been getting it:
It’s not for a lack of supply. 1 million doses have been delivered, but no one is getting them.
Some people did say they were waiting for it. Here’s a representative tweet:
Many others were certain Novavax would be better, and that there was even a conspiracy to suppress it:
I think that other people just never plan to get any vaccine, and they come up with arguments as excuses.
Calling the Pfizer vaccine “gene therapy” was just an excuse, a line that sounded good. It wasn’t the actual reason they didn’t get it.
Many think the shots are unnecessary because they don’t believe covid is dangerous. Some don’t even think that covid exists. Covid is politicized — many Republicans have decided that worrying about covid is a form of liberal hysteria, they’re looking for reasons why the vaccines are dangerous as an excuse to argue with liberals.
When a person complains that the Pfizer vaccine is “experimental gene therapy”, what they’re usually saying is that it’s important for their political identity to fear the vaccine but not fear covid.
This hasn’t played out well for Republicans — the pandemic has been killing them at a higher rate than Democrats:
Despite their flaws, the mRNA vaccines save lives. They’re safer than getting covid.
I tried asking some of these people what they thought of Novavax:
They’re scared because the Novavax spike protein is made in moth cells.
The full process looks like this:
The spike protein is created inside a moth cell, extracted, and then built into those spiky nanoparticles.
I doubt these people are actually afraid of moths.
They just like making excuses.
For a while, people objected to getting the Pfizer vaccine because it “wasn’t FDA approved”. It was first given out under Emergency Usage Authorization.
Then, it did get full FDA approval. And no one changed their mind and went out to get vaccinated.
Some claimed that it was a bait and switch, that there is an approved vaccine sitting around somewhere, but the authorities are still giving out a different experimental vaccine:
Now they’ve latched onto the fact that the Novavax company grows the spike protein in moth cells.
Naturally, that means it must be dirty. Or dangerous. Or it’s going to turn you into an insect. Or something.
For comparison, flu shots are made in chicken eggs. I’ve never heard anyone afraid of that. In truth, some people do get an allergic reaction to flu shots precisely because they’re allergic to eggs.
This is actually an incredibly old form of fearmongering. A few hundred years ago, we used cowpox to vaccinate against smallpox. Cowpox was a live virus that caused mild illness. The infection gave immunity against the much more severe smallpox virus.
The word vaccine actually comes from this. The latin word for cow is “vacca”, about the same as “vaca” in Spanish or “vache” in French. The cowpox virus was called the “vaccinia” virus.
Here’s some antivax propaganda from the time:
The smallpox vaccine didn’t actually turn anyone into a cow.
And, to the best of my knowledge, Novavax has not yet turned anyone into Mothra.
But, I don’t know, not that many people have gotten Novavax yet.
It could still happen. Keep your eyes on the VAERS reports for more Novavax safety data and possible giant moth sightings.
