Earlier in the day, AstraZeneca resumed clinical trials of its vaccine, developed jointly with the University of Oxford following a brief suspension after one of the participants suffered a side effect last week, causing transverse myelitis, an inflammation of spinal cord.
CEO Kirill Dmitriev on Saturday said that temporary suspension of AstraZeneca COVID-19 vaccine candidate trials clearly showed the "fallacy of the approach" when countries "exclusively rely on novel and untested platforms" while choosing a vaccine for widespread use.
AstraZeneca and the University of Oxford, as the trial sponsor, can not disclose further medical information, the statement adds.
Oxford University confirmed the resumption and said: "In large trials such as this, it is expected that some participants will become unwell and every case must be carefully evaluated to ensure careful assessment of safety".
On September 6, the standard review process in the ongoing trials of the vaccine candidate triggered a "voluntary pause to vaccination" across global sites so that independent committees and worldwide regulators could review safety data related to the vaccine, AstraZeneca said.
The company said it will continue to work with health authorities "across the world" and will "be guided" as to when other clinical trials can resume.
Dmitriev added that the push by Western pharmaceutical companies for indemnity from lawsuits over vaccines illustrates the uncertainty surrounding monkey adenoviruses and mRNA technology - another untested method of vaccine development.
In June, UK firm AstraZeneca had signed a pact with Serum for manufacturing a billion doses of the vaccine at its Pune facility.
Speaking with PUNCH HealthWise in an exclusive interview, the physician said Russian Federation "jumped the gun" by hastily approving the vaccine for use, without completing the processes vaccines undergo before they're considered safe for public use.
In its statement, AZ said it would update all trial investigators and participants with relevant information, which would be disclosed on global clinical registries, according to the clinical trial and regulatory standards.
The Brazilian state of Bahia has agreed to conduct Phase III clinical trials of the vaccine.
In comparison, Oxford's vaccine uses a harmless virus - a chimpanzee cold virus, engineered so it can't spread - to carry the coronavirus' spike protein into the body, which should trigger an immune response.
Although many of these experimental vaccine candidates are in the phase-3 trials, "there is no guarantee that any of these six will give us the answer", as Michael Ryan, executive director of the WHO Health Emergencies Program said in August.
Business Secretary Alok Sharma said: "I am immensely proud that the United Kingdom is home to two of the most promising Covid-19 vaccine candidates, backed by over £130million of government funding to speed up the search for a vaccine and end the pandemic sooner". The vaccine, co-developed with National Institute of Allergy and Infectious Diseases, underwent trials at 89 sites across the US.