Governments are desperate for a successful vaccine to help put an end to the COVID-19 pandemic that has caused 900,000 deaths worldwide as well as economic unheaval.
Among the many vaccine trials underway, the WHO had flagged the AstraZeneca vaccine being developed within the University of Oxford as the most promising.
However, AstraZeneca suspended late-stage trials on its potential vaccine this week after an illness in a participant in Britain who was reported to be suffering from symptoms associated with transverse myelitis, a rare spinal inflammatory disorder.
AstraZeneca should still know by year-end whether its experimental vaccine protects people against coronavirus, as long as it is cleared to resume trials soon, its chief executive said on Thursday amid doubts over its rollout.
AstraZeneca CEO Pascal Soriot said on Thursday that they did not yet know the diagnosis of the ill participant, adding that more tests were necessary to be clear if the patient had transverse myelitis. An independent safety committee would determine whether trials can be resumed.
Soriot also said that disruptions to vaccine trials were very common, but that the world is typically not watching vaccine trials as is the case with the COVID-19 vaccine trials.
Transverse myelitis cases after a vaccination have been documented before, but concrete links between the condition and vaccinations have not been established, experts said.
The U.S. based Mayo Clinic concludes that the association so far is not worthy of limiting any vaccines.
A 2009 review in the journal Lupus of nearly 40 years of English-language publications found 37 cases of transverse myelitis associated with hepatitis B vaccines, measles-mumps-rubella, diphtheria-tetanus-pertussis and others.
Story from Reuters.