AstraZeneca has paused its Phase 3 trial of the COVID-19 vaccine developed in collaboration with the University of Oxford, after a suspected serious adverse event in a trial participant.
AstraZeneca said it initiated the study hold. The nature of the adverse condition, when and where it happened (most likely in the UK) were not immediately known, although the participant is expected to recover, according to an individual familiar with the matter. www.statnews.com/...
Here is the statement from AstraZeneca -
From www.nytimes.com/… — “according to an anonymous source, a volunteer in the U.K. trial had been found to have transverse myelitis, an inflammatory syndrome that affects the spinal cord and is often sparked by viral infections. However, the timing of this diagnosis, and whether it was directly linked to AstraZeneca’s vaccine, remains unclear.”
Vaccines are known to cause Transverse Myelitis — see pubmed.ncbi.nlm.nih.gov/…. Rare, but debilitating. So, this require investigation to ascertain whether the condition was caused by the vaccine or whether it was due to some other unrelated reason.
Some words of reassurance -
AZD1222
Oxford University’s Jenner Institute and Oxford Vaccine Group developed the vaccine known as AZD1222. The candidate vaccine was licensed to AstraZeneca for further development. The vaccine uses a non-replicating chimpanzee adenovirus to deliver a SARS-CoV-2 spike protein to induce an immune response.
AstraZeneca began its Phase 3 trial in the U.S. in late August. Phase 2/3 trials were previously started in the U.K., Brazil (June 28) and South Africa.
The Phase 3 trial in the U.S. aims to enroll about 30,000 participants at 80 sites across the country, according to a release last week from the National Institutes of Health.
The US Operation Warp Speed program has invested $1.2B in the AstraZeneca/Oxford vaccine.
AstraZeneca PLC (AZN) stock is down 8% in after-hours trading.
A Synopsis of the leading vaccine candidates
The following table shows the leading vaccine efforts organized by vaccine type and country. Note that there are many more vaccines in clinical trails than the subset shown below.
| COUNTRY |
GENETIC (MRNA, DNA) |
VIRAL VECTOR |
PROTEIN BASED |
WHOLE VIRUS |
| USA |
Moderna (3)
Innovio (2)
|
J&J+IDMC (1/2)
Merck+IAVI (pre)
|
Novovax (2)
Sanofi/GSK (1)
|
|
| Europe |
Pfizer+BioNTech (3)
Imperial College+
Morningside (1/2)
Curevac (2)
|
University of Oxford + AstraZeneca (3)
|
|
|
| China |
People's Liberation Army (PLA) Academy of Military Sciences/Walvax Biotech (1/2) |
CanSino (3)
|
Clover Biopharm (1)
|
Sinovac (3)
Sinopharm (3)
Institute of Medical Biology (2)
|
| Russia |
|
Gamaleya Research Institute (3) |
|
|
Notes
- Note that the table has 5 columns. Scroll right if necessary.
- Clinical trial phase is shown in parenthesis.
- Companies funded by the U.S. Operation Warp Speed (OWS) program are indicated in bold.
None of the phase 3 trials are fully recruited yet, so it is difficult to imagine how results can be produced in the next 2 months. Participants will need a second dose after a month. Typical phase 3 vaccine trials run for years, not weeks.
OWS Funding
| ORGANIZATION |
OWS FUNDING |
DOSES IN INITIAL CONTRACT |
LINKS |
| Moderna |
$483 million |
|
www.hhs.gov/... |
| University of Oxford + AstraZeneca |
Up to $1.2 billion |
300M |
www.hhs.gov/... |
| Pfizer + BioNTech |
$1.95 billion |
100M |
www.hhs.gov/... |
|
J&J + Beth Israel Deaconess Medical Center
|
$456 million |
|
link
|
| Merck + IAVI |
? |
|
|
| Novavax |
Up to $1.6 billion promised |
100M |
link
|
| Sanofi + GSK |
Up to $2 billion |
100M |
link |
On Aug 27, the CDC sent instructions to states to prepare for limited quantities of 2 vaccines by early November (appears to be Pfizer/BioNTech and Moderna, both mRNA based vaccines) — www.nytimes.com/…
Epilogue
It is not unusual for vaccine trials to be put on hold, when an adverse reaction is detected in one of the participants. This is why they conduct large scale phase 3 trails, with upwards of 30,000 participants, over an extended period of time (years). Vaccines are not entirely risk-free, but safety assessment is critical, even though the vast majority of participants suffer minor side effects. Understanding why serious reactions occur in certain participants is important to reducing the probability of such occurrences when the vaccine is administered to millions of people. Similarly, efficacy is difficult to assess with small trials or with a truncated trail that lasts only a few weeks.
Hopefully, the AstraZeneca situation will be resolved soon. Hopefully, the adverse condition is not caused by the vaccine. And hopefully, this will help slow down the mad rush by the trump administration to release a vaccine before election day.
