CHICAGO (Reuters) - U.S. government scientists have begun efforts to manufacture a strain of the novel coronavirus that could be used in human challenge trials of vaccines, a controversial type of study in which healthy volunteers would be vaccinated and then intentionally infected with the virus, Reuters has learned.The work is preliminary and such trials would not replace large-scale, Phase 3 trials such as those now under way in the United States testing experimental COVID-19 vaccines from Moderna Inc (MRNA.O) and Pfizer Inc (PFE.N), according to a statement emailed to Reuters by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.
U.S. officials organizing the fight against the pandemic have been under pressure from advocacy groups such as 1 Day Sooner and others that see challenge trials as a way to speed up tests of a COVID-19 vaccine. Most vaccine trials rely on inadvertent infection, which can take time to occur.
Some drugmakers, including AstraZeneca (AZN.L) and Johnson & Johnson (JNJ.N), have said they would consider human challenge trials to test COVID-19 vaccines if needed.
"Should there be a need for human challenge studies to fully assess candidate vaccines or therapeutics for SARS-CoV-2, NIAID has begun investigations of the technical and ethical considerations of conducting human challenge studies," the agency statement said.
That includes efforts to manufacture a suitable SARS-CoV-2 strain, draft a clinical protocol and identify resources that would be required to conduct such studies.
Small challenge studies would be done in small isolation units to control the virus. Larger challenge studies involving 100 people or so would have to be done in multiple locations, adding months of preparations to coordinate the studies.