CEPI was launched in 2017 to fund epidemic vaccine development and
is funded by countries across the globe as well as by the Bill &
Melinda Gates Foundation.
Major vaccine studies have so far examined COVID-19 infection rates
comparing the prospective vaccine with a placebo.
Such trials may no longer be considered ethical in countries where
an effective vaccine is widely available.
Instead, new vaccines would need to be tested in comparison to an
established shot, involving two groups of trial volunteers, CEPI
said.
A rate of protection or blood analysis measuring so-called
immunogenicity that is comparable to or better than the established
product would lead to approval, it said.
CEPI said incumbent shots are often not made available, hindering
the development of a wider variety of vaccines.
"Lack of access to comparator vaccines is already stalling the
development of promising vaccine candidates, and the potential
impact on COVID-19 vaccine development and supply is huge," Melanie
Saville, director of vaccine research and development at CEPI, said
in a statement posted on the organisation's website.
A version of the statement was also published as a letter to the
editors of scientific journal Nature.
Established vaccine manufacturers have committed production capacity
to serve immunisation campaigns in various nations but those supply
contracts do not foresee any use in clinical trials, according to
CEPI.
"Thus far, vaccine manufacturers have been reluctant to change this
arrangement, threatening to bring vital COVID-19 vaccine R&D to a
standstill," CEPI's Saville said.
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"Companies that have a big
market advantage or are selling lots of doses
are not very motivated to participate in a trial
in which another vaccine might be seen to be
comparable or potentially even more
immunogenic," Nicole Lurie, CEPI's U.S. director
and strategic adviser to the CEO, told Reuters.
She added countries also need to re-negotiate their procurement
contracts with manufacturers to free them to transfer doses for use
in trials.
Volumes in the tens of thousands of doses would already make a huge
difference for trials, which is small compared to the hundreds of
millions being delivered, she added. Top Western
suppliers are the BioNTech-Pfizer partnership and AstraZeneca
working with Oxford University, with each having distributed more
than a billion doses.
AstraZeneca's Vaxzevria-branded shot, however, has been obtained by
challengers.
Planned or ongoing vaccine trials that use Vaxzevria as a comparator
include Italy's ReiThera Srl, Valneva of France, Taiwan's Medigen
Vaccine Biologics and South Korea's SK Bioscience.
A Valneva spokesperson said the trial was recruited quickly and she
was not aware of difficulties in procuring the Astra doses.
(Reporting by Ludwig Burger; additional reporting by Richard Lough;
editing by Jason Neely)
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