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The Inside Story on the AZ Vaccine Pause

AstraZeneca has resumed its big coronavirus trial in the UK. The vaccine pause is still in effect in the U.S. Why is there a discrepancy?
The Inside Story on the AZ Vaccine Pause
Doctor giving patient vaccine, flu shot. Doctor making a vaccination in the shoulder of patient

The world is holding its breath for a safe and effective vaccine against COVID-19. This week there was more than enough conflicting information about when a vaccine will become available. In the meantime, though, there is still some mystery surrounding the temporary vaccine pause for AZD1222. That’s the name of the Oxford University/AstraZeneca vaccine that is part of Operation Warp Speed. It is in phase 3 clinical trials in Brazil, Great Britain, South Africa and United States. The vaccine pause has been lifted in the UK, Brazil and South Africa, but not in the U.S.

Fast Vaccine Development!

The AZ vaccine is part of Operation Warp Speed. The U.S. government announced that it would spend as much as $1.2 billion on this one vaccine. That was before any results were in.

Researchers in the U.S. were trying to recruit subjects at up to 80 different sites. The worldwide goal: 30,000 participants. Everyone would like to see the trial proceed as fast as possible.

The word from the University of Oxford was that the vaccine pause was necessary:

“to allow the review of safety data by an independent safety review committee, and the national regulators.”

Back in Business:

Now, the review has determined that the vaccine pause is no longer necessary. The analysts have concluded that the neurological complications that were associated with AZD122 were not caused by the vaccine.

Patients are once again being recruited. But very little information has been released by either AstraZeneca or Oxford University. We have not been able to assess the nature of the adverse reactions that led to the vaccine pause in the first place.

Vaccine Pause Not Lifted in the US, Yet:

U.S. regulators appear more cautious than their European counterparts. Dr. Avinda Nath is a key player in viral research at the National Institute for Neurological Disorders and Stroke.

Here is his take on the NIH review of AZD1222:

“The highest levels of NIH are very concerned. Everyone’s hopes are on a vaccine, and if you have a major complication the whole thing could get derailed.”

The hope was that this vaccine might start rolling off production lines sometime in October. The vaccine experts we have consulted believe that this timeline is too optimistic. Even if all the testing goes perfectly and vaccines are proven both safe and effective, these insiders are predicting availability sometime in 2021.

Explaining Away the Vaccine Pause:

AstraZeneca has stated that this review of safety data is a standard operating procedure:

“This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated.”

The drug company went on to explain that:

“In large trials, illnesses will happen by chance but must be independently reviewed to check this carefully.”

Why This Vaccine Pause Was More Worrisome:

What we have heard through the grapevine is that the volunteer who experienced the health problem was not in the placebo group. If that were the case the “unexplained illness” would not have led to a vaccine pause.

Then there was the diagnosis. Transverse myelitis is a serious inflammatory condition that can be triggered by a viral infection.

What Is Transverse Myelitis?

This is a nasty and relatively rare neurological condition affecting the spinal cord. The myelin sheath that surrounds nerves becomes inflamed. Neuronal impulses become interrupted.

Patients may experience pain in their back, arms, legs or neck. Muscle weakness in the legs or upper extremities is another red flag. Symptoms can include stumbling, foot dragging or a feeling of heaviness in arms or feet. This may be accompanied by numbness, tingling or burning sensations. Even more alarming is the loss of bowel or bladder control.

What causes transverse myelitis? To be perfectly honest, the exact etiology, to use doctorspeak, is mysterious. As mentioned above, viral infections are a prime suspect. Neurologists suspect that some patients may develop this disorder as a result of an autoimmune reaction. It can also be triggered by vaccinations. 

One of the world’s leading vaccine experts is Dr. Paul Offit. We recently interviewed him on The People’s Pharmacy about about vaccines for COVID-19 at this link

Show 1225: What Is the Evidence on Vaccines and Masks?
Dr. Paul Offit, a leading expert on vaccinology, discusses how we will get good evidence on vaccines for COVID-19

On September 9, 2020, Dr. Offit responded to a question from NPR Morning Edition host Noel King about the AZ vaccine pause:

“KING: How unusual is it for something like this to happen during a vaccine trial?

“OFFIT: It’s not common, but it’s certainly not unheard of. It does happen when, presumably, someone had a serious adverse event soon after receiving the vaccine. And then the company just stops, takes a much closer look at that particular case to try and answer the question, was this a coincidental association or was it a causal association?

“…So I think it’s prudent of this company to do what they’re doing – stop, take a much closer look at this case and try and answer the question, was this because of the vaccine?”

Can Vaccines Cause Transverse Myelitis?

As we mentioned above, transverse myelitis has been linked to vaccinations (International Journal of MS Care, March-April, 2020; Autoimmunity Reviews, March, 2014). AstraZeneca has been pretty tight-lipped about the details of the AZD1222 vaccine pause. The CEO of AstraZeneca told investors that the woman volunteer who experienced a rare spinal cord inflammatory disorder was improving.

He also revealed that the clinical trial had been halted briefly once before. Another participant reported neurological symptoms, but the company chalked them up to multiple sclerosis (MS) and concluded that they were unrelated to AZD1222.

Vaccines stimulate an immune reaction that can occasionally trigger demyelination of nerves in the central nervous system. Multiple sclerosis is a devastating neurological condition that occurs when the immune system begins attacking the myelin sheath (aka demyelination).

Where Do We Go from Here?

No one knows how long it will take U.S. reviewers to analyze the adverse reaction data from the UK. There is a lot riding on this clinical trial, so we suspect that there is a lot of pressure to get the U.S. clinical trials back up and running as soon as possible. And now that the vaccine pause has been lifted in the UK, Brazil and South Africa, the pressure will be even greater.

There are at least seven other companies testing vaccines in phase 3 clinical trials. Two companies, Moderna and Pfizer, are testing mRNA vaccines. Each is recruiting about 30,000 volunteers.

Messenger RNA technology is very different from the Oxford/AstraZeneca vaccine. AZD1222 relies upon a genetically modified virus extracted from chimpanzees. This adenovirus contains a gene from a protein on the SARS-CoV-2 virus. It is supposed to teach the human immune system to recognize the coronavirus and stimulate a strong response. We hope it clears its safety review in a timely fashion and the clinical trial can resume. 

We have our fingers crossed that the Moderna and Pfizer mRNA vaccines do not get halted because of any serious adverse reactions. And we hope that U.S. regulators will be more transparent about the adverse reactions that led to the temporary vaccine pause in the UK. We are also hopeful that the Warp Speed process doesn’t take any short cuts when it comes to safety or efficacy.

How Soon Will a Vaccine Be Ready for Prime Time?

Can these vaccines be introduced to the public over the next several weeks? Let us tell you why we think that’s a stretch. First, the companies are still recruiting volunteers. It could take several more weeks before this process is complete.

Second, everyone enrolled in these phase 3 clinical trials will need to get two shots. The second “booster” is given one month after the first injection. Then the investigators have to wait two weeks for full immunity.

The biggest challenge will be waiting for the people who receive placebo injections to come down with COVID-19. There have to be quite a few cases of illness to prove the vaccines are better than an inactive saline injection.

Remember, investigators cannot ethically tell people who are enrolled in their trials to be careless. Most people will likely be advised to wear their masks, maintain physical distance from others and wash their hands. As a result, it could take quite a few more weeks before enough people get sick to demonstrate a statistically significant difference between placebo and vaccine. According to our calculations, that pushes data analysis into 2021.

Dr. Robert Redfield Got Spanked:

We are not the only ones who think this. Dr. Robert Redfield was appointed to head the CDC by the Trump administration in March, 2018.

Here is this week’s prediction from Dr. Redfield during Congressional testimony:

“I think there will be vaccine that will initially be available some time between November and December, but very limited supply, and it will have to be prioritized. If you’re asking me when is it going to be generally available to the American public so we can begin to take advantage of vaccine to get back to our regular life, I think we’re probably looking at late second quarter, third quarter 2021.”

As you may have heard, President Trump criticized Dr. Redfield for this prediction. Many people hope that a vaccine will become available within the next six weeks.

What Do You Think?

We welcome your thoughts about COVID-19 vaccines in the comment section below. Are you concerned about the AZD1222 vaccine pause? Once a new vaccine passes the Data Safety Monitoring Board and gets FDA approval, will you be volunteering to get vaccinated? If not, why not?

You may also want to listen to our podcast with the Coronavirus Hunter, Dr. Ralph Baric. He is also an expert on vaccines and provides some intriguing insights into the future prevention and treatment of COVID-19.

Show 1226: The Coronavirus Hunter Gives You an Update
Dr. Ralph Baric, the coronavirus hunter, gives you an update on the pandemic and what we might expect in the future.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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