Details of the trial were recently published after the company received criticism over the lack of transparency that is surrounding the testing of the experimental vaccine against the virus that causes COVID-19.
The first participant to fall ill after receiving a single dose of the experimental vaccine in July was part of the British trials. This female volunteer has been diagnosed with transverse myelitis which is a rare inflammatory disease affecting the spinal cord, causing weakness, sensory alterations, and autonomic nervous system dysfunction. Later on, a spokesperson for the company said that the volunteer had undiagnosed multiple sclerosis and the trials resumed.
A second female volunteer fell ill and suffered complications after receiving a follow-up dose of the experimental vaccine in September, the dosing regimen for this experimental vaccine requires two injections that are four weeks apart. While the company is not confirming diagnosis a source has told the New York Times that it is also transverse myelitis. The trials were paused after the second female recipient fell ill, but they have resumed again in South Africa, India, Brazil, and Britain less than a week later, while in American the trials are still on hold.
The AstraZeneca experimental vaccine has been administered to over 18,000 people worldwide, and in the internal documents said that the two cases of the illness were “unlikely to be associated with the vaccine, or there was insufficient evidence to say for certain that the illnesses were or were not related to the vaccine.”
While the company is downplaying the two females falling ill saying that it is not related to the experimental vaccine, transverse myelitis is a very serious and rare disease, the repeated cases in previously healthy volunteers of the trials may cause AstraZeneca to lose its bid with their experimental vaccine altogether.
“The larger your study group, the more likely you’ll find an adverse event,” Dr. Mark Slifka of the Oregon Health and Sciences University said. “This could occur spontaneously.”
There are speculations that vaccines may be able to trigger transverse myelitis, and a handful of vaccines have previously been tied to cases of other autoimmune disorders including Guillain-Barre syndrome in which the immune system attacks the nerves, but according to Dr. Felicia Chow who is a neurologist at the University of California San Francisco these complications are rare.
According to Kirill Dmitriev who is the CEO of the Russian Direct Investment Fund that is bankrolling the Russian vaccine development, AstraZeneca’s experimental vaccine is using a monkey adenovirus that shares a gene with the virus that causes COVID-19, and this is an untested method of vaccine development.
Russia’s Sputnik V, which is the world’s first registered vaccine, uses human adenoviruses which is a vector that has been reported as being extensively studied. The Lancet has recently published the Russian Ministry of Health’s Sputnik V Study that is reported as showing promising results with all 76 participants producing antibodies in the early-stage trials.
