Nobel laureates call for 'challenge trials' to speed up vaccine process

Dr Richard Hatchett, CEO of the Coalition for Epidemic Preparedness Innovations, joins Christiane with an update on the urgent search for a Covid-19 vaccine

Posted: Jul 18, 2020 1:50 PM
Updated: Jul 18, 2020 1:51 PM

More than 100 top scientists including 15 Nobel laureates have written an open letter calling for volunteers to be exposed to the coronavirus to assist with vaccine development.

They said so-called "human challenge trials" or "controlled infection trials" were of "vast importance" in speeding up the testing of the vaccines in development around the world.

"If challenge trials can safely and effectively speed the vaccine development process, there is a formidable presumption in favor of their use, which would require a very compelling ethical justification to overcome," the scientists wrote in the letter to Dr. Francis Collins, director of the US National Institutes of Health (NIH).

It urged the US government to undertake immediate preparations for human challenge trials, "including supporting safe and reliable production of the virus and any biocontainment facilities necessary to house participants."

The letter said human challenge trials -- in which volunteers are deliberately exposed to the pathogen under controlled conditions -- can provide information months before conventional efficacy trials, in which candidates receive a vaccine or control and resume their normal life, with the assumption that they may be eventually exposed to the virus.

More than 2,000 challenge trial volunteers also signed the letter published by 1Day Sooner, an organization advocating on their behalf.

Adrian Hill, director of the Jenner Institute at the University of Oxford in England, and signatory of the open letter, wrote in a statement that "collaborative human challenge studies should be feasible and informative in the coming months."

Oxford's Jenner Institute is working with 1Day Sooner to produce a Covid-19 human challenge virus and Hill said it had "considerable potential" for helping to accelerate vaccine development and optimize vaccination approaches.

The World Health Organization (WHO) issued guidance in May saying challenge studies can be "substantially faster" and more effective than other methods, in part because fewer participants need to be exposed to experimental vaccines and because they can be used to compare potential vaccines.

Challenge trials were used in early research with smallpox, yellow fever and malaria, which changed the course of global public health, according to WHO.

Over the past 50 years, tens of thousands of consenting adult volunteers have safely undergone such trials under the oversight of research ethics committees, WHO reported.

It said controlled infection trials could be ethically acceptable if they met certain criteria. These include choosing young and healthy adults as participants, starting with low doses, ensuring public engagement, and providing high-quality care and close monitoring.

The notion of a human challenge trial for Covid-19 was jump-started by a March 31 article in the Journal of Infectious Diseases, which made the case that the nature of the global emergency warranted consideration of unconventional approaches.

Co-authored by Nir Eyal of Rutgers, Marc Lipsitch of Harvard, and Peter Smith of the London School of Hygiene & Tropical Medicine, the piece concluded that while a human challenge study would not be without risks, "every week that vaccine rollout is delayed will be accompanied by many thousands of deaths globally."

But members of the NIH's Accelerating Covid-19 Therapeutic Interventions and Vaccines (ACTIV) Vaccines Working Group said earlier this month that challenge trials would not speed up vaccine development.

In a commentary published in the New England Journal of Medicine, ACTIV members wrote that using controlled human infection models to support vaccine development requires "essential criteria" to limit the risk for participants and could take "one to two years."

"A single death or severe illness in an otherwise healthy volunteer would be unconscionable and would halt progress," they wrote.

They said it would be unethical to organize an experiment in which people were deliberately infected unless there were a rescue therapy -- a treatment that can save lives -- which does not exist for coronavirus.

"Large, randomized, controlled trials of SARS-CoV-2 vaccines are currently the most efficient, generalizable, and scientifically robust path to establishing vaccine efficacy," the authors concluded.

Indiana Coronavirus Cases

Data is updated nightly.

Cases: 657037

Reported Deaths: 12450
CountyCasesDeaths
Marion901321624
Lake48105871
Allen35552632
Hamilton31839393
St. Joseph29538510
Elkhart25261412
Vanderburgh21115377
Tippecanoe19765197
Johnson16242352
Porter15838267
Hendricks15723296
Clark11843179
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Monroe10248158
Delaware9788178
LaPorte9720194
Howard9017194
Kosciusko8514107
Bartholomew7373147
Warrick7369146
Hancock7362128
Floyd7139164
Wayne6586188
Grant6395157
Morgan6040124
Boone603388
Dubois5868111
Dearborn540266
Henry539492
Marshall5390104
Cass537199
Noble506775
Jackson462063
Shelby458490
Lawrence4154111
Gibson399681
Harrison395160
Clinton392353
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Knox354484
Miami354063
Whitley346235
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Steuben335955
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Wells255374
Scott248446
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Randolph225076
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Owen181652
Jay177328
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Martin80114
Switzerland7507
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Union66810
Ohio52711
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Ohio Coronavirus Cases

Data is updated nightly.

Cases: 958153

Reported Deaths: 16968
CountyCasesDeaths
Franklin1109381191
Cuyahoga944201702
Hamilton72486944
Montgomery46927869
Summit39637941
Butler35004461
Lucas34724755
Stark29011826
Warren22137269
Lorain21738385
Mahoning19251533
Lake18178300
Clermont18172206
Delaware16261128
Licking14820194
Fairfield14378157
Trumbull14136454
Greene13470209
Medina13188218
Clark12121332
Wood11384193
Portage10829152
Allen10710231
Richland10165198
Miami9937179
Columbiana8049179
Muskingum8036123
Tuscarawas7974233
Pickaway795898
Marion7936134
Wayne7791216
Erie6783181
Ross6065135
Geauga5978129
Hancock5941110
Scioto5867105
Ashtabula5811140
Lawrence519073
Union505052
Darke5006122
Belmont484787
Sandusky472393
Jefferson4709107
Huron4701116
Seneca4620103
Athens456231
Mercer4559101
Auglaize453896
Washington451286
Shelby438867
Knox397884
Putnam3964101
Madison388747
Ashland374594
Fulton374364
Defiance3670101
Brown366742
Crawford354296
Preble350570
Logan349757
Clinton336162
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Ottawa318467
Williams299578
Jackson287056
Guernsey283234
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Perry265239
Morrow256624
Henry242665
Hardin241856
Holmes2416104
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Gallia219446
Adams213732
Pike212025
Wyandot207652
Hocking192148
Carroll178828
Paulding158423
Meigs133536
Noble127842
Monroe114936
Harrison99132
Morgan98834
Vinton76215
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