Exclusive: U.S. to make coronavirus strain for possible human challenge
trials
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[August 14, 2020]
By Julie Steenhuysen
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.
Such trials are typically done when a virus is not widely circulating,
which is not the case with COVID-19. Many scientists consider human
challenge trials of the novel coronavirus unethical because there are no
"rescue therapies" for those who fall ill.
Earlier this week, Johan Van Hoof, global vaccines chief for J&J, said
in an interview with Reuters that the preparations for such trials are
under way across the world, and the company is following those
preparations.
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A small bottle labeled with a "Vaccine" sticker is held near a
medical syringe in front of displayed "Coronavirus COVID-19" words
in this illustration taken April 10, 2020. REUTERS/Dado Ruvic//File
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Van Hoof said such trials would offer a testing option in case the
virus stops circulating widely, but the company would only move
forward with such trials if the ethical issues are resolved and an
effective treatment is available.
Dr. Anna Durbin, a vaccine researcher at the Johns Hopkins Bloomberg
School of Public Health, who has run a dozen challenge studies,
estimates it could take nine to 12 months to set up a human
challenge trial, and another six months to coordinate testing across
multiple testing sites.
NIAID said it is continuing to prioritize field trials to evaluate
SARS-CoV-2 vaccine candidates, but it opened the possibility to
challenge trials for future generations of vaccines or treatments.
Dr. Dan Barouch, a vaccine researcher at Harvard's Beth Israel
Deaconess Medical Center in Boston, who helped design and conduct
animal studies on J&J's COVID-19 vaccine, said he is not aware of
any manufacturers planning human challenge studies.
"In the setting of a pandemic that is raging, you don't need it. You
just do a trial and get a real result," he said.
Moreover, vaccine trials would have to be done in healthy young
people, said University of Maryland School of Medicine's Dr.
Kathleen Neuzil, co-leader of the Coronavirus Vaccine Prevention
Network, which was formed by NIAID and is testing COVID-19 vaccines.
"A 20-year-old in a challenge study isn't really going to give us
the answer of will this vaccine keep an older person, someone with
chronic kidney disease, from ending up in the hospital," she said.
(Reporting by Julie Steenhuysen; Additional reporting by Francesco
Guarascio in Brussels; editing by Peter Henderson and Leslie Adler)
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