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At the end of the year, AstraZeneca really wanted to bring an effective and safe vaccine to market. The British-Swedish pharmaceutical company has even signed contracts for millions of doses of vaccines that should be distributed around the world once the product is approved and manufactured.
The setback came Wednesday night: AstraZeneca had to interrupt its final clinical study for now because a test person suspected serious side effects. What are the consequences of the news for global vaccine research and for Germany? The summary.
What does the suspension of the study mean?
The study was not completely stopped, it was only interrupted for the moment. “As a standard, new vaccines are exposed first so that possible side effects can be examined more closely,” says Bernd Salzberger, head of the Department of Infectious Diseases at Regensburg University Hospital, who is not involved in the studies.
Caution must be exercised, after all, millions of people can be vaccinated. Just a day ago, nine leading pharmaceutical companies had joined in and, despite time pressure, promised the development of safe vaccines, including AstraZeneca.
“For me, the procedure in the case of AstraZeneca’s vaccine studies is a good sign because it shows that the safety rules are taking effect,” says Stephan Becker, director of the Institute of Virology at Philipps University of Marburg. It is unfortunate that a study subject is ill, but important information is still lacking to evaluate the case.
Therefore, stopping clinical trials is part of the quality assurance process and is intended to ensure the protection of test subjects.
What type of vaccine is it?
The AZD1222 vaccine is also known as the Oxford vaccine because it was developed by the Jenner Institute at the University of Oxford. It is one of the so-called vector vaccines.
Viruses that are harmless to humans are “disguised” as the new type of coronavirus with the help of genetic engineering. To do this, the researchers exchange certain proteins on their surface for typical components of the pathogen. They are supposed to simulate an infection in the body, but do not make it sick. The theory is that anyone who is vaccinated with these vector viruses forms antibodies that also protect against an actual infection. The first approved Ebola vaccine works on this principle.
Initial studies with the Oxford vaccine also showed promising results. It is based on chimpanzee adenoviruses into which coronavirus genes have been introduced. Adenoviruses are considered harmless to humans. However, it is suspected that they can trigger immune reactions that are directed against your own body in rare cases. It is now being investigated whether this might have been the case with one of the test subjects.
What is known about the side effect?
According to reports from the New York Times, one of the subjects developed transverse myelitis. AstraZeneca has not confirmed this at SPIEGEL’s request, but announced that it will voluntarily pause more vaccines.
Transverse myelitis is an inflammation of the spinal cord and can occur as a result of a viral infection. “Most of the time, transverse myelitis is not caused by the pathogen itself, but by an overreaction of the immune system,” says Peter Berlit, secretary general of the German Society for Neurology, SPIEGEL.
Therefore, an immune reaction to a vaccine is a plausible explanation for transverse myelitis, but not the only one. For example, the disease could also indicate the autoimmune disease multiple sclerosis.
If one of the subjects did develop spinal cord inflammation, further examinations would have to show what the probable cause was. “If multiple sclerosis and other known causes can be ruled out,” says neurologist Berlit, “and both an MRI and an examination of the nerve fluid indicate inflammation, that would be a possible indication that the disease was the result of vaccination.” .
The symptoms of transverse myelitis depend on which parts of the spinal cord are affected; At worst, those affected remain paralyzed. However, if patients are treated quickly, there is the possibility of a complete cure.
It’s unclear how the study subject is doing. He is said to have participated in a phase 2/3 study in Britain, the New York Times reports, citing an insider who claims to have been involved in the case but wants to remain anonymous.
Phase I, II, III – what does that mean?
The vaccine is given to a small group of healthy volunteers. It is observed if the agent basically fulfills its purpose, that is, if it causes an immune response. And check how safe it is, that is, what side effects occur. You can also try different doses to find the optimal one.
Now the vaccine will be administered to a greater number of participants, some of whom belong to risk groups. In the case of Covid-19, they would be the elderly or people with previous illnesses. During this phase, more tests are carried out to determine if the vaccine is working, that is, if it prevents disease, and what dose is appropriate. To save time, some phase I and II studies are currently being combined.
The vaccine will be tested on a large group of volunteers; this can be tens of thousands. In phase III, the efficacy, safety and dosage of the vaccine are confirmed. Adverse events, such as a particularly severe course of the disease due to the administration of the vaccine, can be observed and ruled out.
What’s next now?
“Now we need information on whether the test subject belongs to the vaccine or to the study control group, whether he has pre-existing or concomitant diseases; above all, other viral infections need to be clarified,” says virologist Becker. “When everything is resolved and the explanation is left that the disease is a side effect of the vaccine, a risk assessment must be carried out.” The risks of the vaccine would have to be weighed against the risks of the Covid 19 disease.
If the risk of a side effect is judged too high, the entire series of tests will be stopped. The so far promising Oxford vaccine would probably not reach the market in its current form.
However, according to AstraZeneca, provisional stop is initially a routine action that is carried out whenever potentially unexplained disease occurs in a study. “These can also occur randomly in large clinical studies, and it is important that the cause is carefully investigated,” the British-Swedish pharmaceutical company said when asked by SPIEGEL. The case should now be examined quickly in order to “keep the possible effects in the time frame of the study as low as possible”.
The vaccine is currently in phase 2/3 trials in the UK and India and phase 3 trials in Brazil, South Africa and the United States. In the United States alone, 30,000 subjects must be included in the study. Due to current developments, more vaccines are now being stopped. Anyone who has already been vaccinated will continue to be watched.
What vaccines could still be affected?
In addition to AstraZeneca, several manufacturers are still investigating vector vaccines against Sars-CoV-2: for example, the Chinese company Cansino Biologics, the American manufacturer Johnson & Johnson, and the controversial Russian vaccine “Sputnik V” is a vector vaccine.
Johnson & Johnson’s Janssen-Cilag from Neuss near Düsseldorf recently received approval to test a vector vaccine in Germany in a phase 2 study. This vaccine is also based on adenovirus. It is not clear if these studies will also be stopped due to possible side effects from the Oxford vaccine.
What vaccines are currently being tested in Germany?
In addition to the Janssen vector vaccine, so-called mRNA vaccines from the Curevac company from Tübingen and the Biontech company from Mainz are also being tested in healthy volunteers in Germany. These vaccines contain parts of the coronavirus model and are intended to stimulate human cells to produce parts of the pathogen on their own. These shouldn’t make you sick, but instead trigger an immune reaction that also protects against coronavirus infection. However, no human vaccine based on this technology has yet been approved.
