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 Executives from Moderna Inc and Pfizer Inc and partner BioNTech SE
are considering new versions of their vaccines to respond to the
most concerning variants identified so far. That is just one piece
of the work needed to stay ahead of the virus, nearly a dozen
experts told Reuters.
A global surveillance network to assess emerging variants must be
built. Scientists need to establish what level of antibodies will be
required to protect people from COVID-19 and determine when vaccines
need to be altered. And regulators must convey what is needed to
demonstrate updated vaccines are still safe and effective.
"At this point, there is no evidence that these variants have
changed the equation in terms of protection from the vaccine," said
Dr. Michael Osterholm, an infectious disease expert at the
University of Minnesota. “But we have to be prepared for that."
Johnson & Johnson told Reuters the concerning variant first
identified in South African has got its attention and will tweak its
vaccine accordingly if needed. Pfizer said it could produce a new
vaccine relatively quickly, but a top vaccine executive said
manufacturing it presents additional challenges.
The urgency of this effort is clear.
Moderna on Monday said lab studies showed antibodies made in
response to its vaccine were six times less effective at
neutralizing a lab-created version of a South African variant than
prior versions of the virus.
A study released on Wednesday ahead of peer review found the South
African variant reduced neutralizing antibodies 8.6-fold for the
Moderna vaccine and by 6.5-fold for the Pfizer/BioNTech shot,
although a separate Pfizer-backed study released on Wednesday
suggests its vaccine may be more hardy. Moderna said this week it is
starting work on a potential booster shot.
COULD TAKE MONTHS
Just how far protection can drop before a COVID-19 vaccine needs to
be altered is not yet known. With influenza, an eightfold drop in
vaccine-induced antibody protection means time to update. That does
not necessarily apply to this coronavirus.
"The problem is we don't know what the cut point is for coronavirus,"
said Dr. John Mascola, director of the Vaccine Research Center at
the National Institute of Allergy and Infectious Diseases (NIAID),
whose scientists helped develop Moderna's vaccine.
Mascola said both studies testing the Moderna vaccine against the
South African variant are roughly in the "same ballpark." It could
be that antibody protection is high enough from the vaccine that it
will still be effective, he said.
NIAID scientists are analyzing data from Moderna's late-stage trial
to see what level of neutralizing antibodies is required for
protection. They are comparing individuals who were vaccinated but
got sick anyway to vaccinated people who remained healthy.
It could take two months to complete this work, Mascola said. They
hope to produce a benchmark for the minimum level of vaccine-induced
antibodies needed to protect against COVID-19.
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 A global surveillance network
is also needed to identify troubling new
variants as they emerge, similar to one used to
track fast-mutating flu viruses. That could cost
tens to hundreds of millions of dollars in the
United States alone.
Richard Webby, a flu surveillance expert from
St. Jude Children's Research Hospital, said the
United States could probably build a system to
identify variants fairly quickly. Developing the
capability to determine whether they evade
current vaccines will take more time.
The United States is currently conducting genetic sequencing to look
for changes in the virus in just 0.3% of positive coronavirus tests.
That pales compared with 10% in the UK, which was first to discover
a major mutation in the virus that increases transmission by at
least 50%. Experts said countries should sequence at least 5% of
positive cases to detect significant changes in the virus.
Companies are waiting for the U.S. Food and Drug Administration to
relay what testing will be needed for altered vaccines, said Phil
Dormitzer, one of Pfizer’s top viral vaccine scientists. With
influenza vaccines, companies can make changes without new trials.
“But that's after doing it for 50 years,” he said.
Peter Marks, who oversees the FDA's vaccine approval process, has
said small trials testing updated vaccines in around 400
participants may be needed at first. Even that could add months to
the process. Norman Baylor, chief executive of
Biologics Consulting and a former FDA vaccines official, said the
agency will lay out the regulatory road. But public health agencies
like the U.S. Centers for Disease Control and Prevention and the
World Health Organization would decide when vaccines should be
updated, as with flu.
Altering Pfizer's vaccine would require "a very minor change,"
Dormitzer said.
Like Moderna’s, it uses messenger RNA (mRNA) technology, which
relies on synthetic genes that can be generated and manufactured in
weeks.
He estimates the company could make a prototype version in a week or
so, and take another two months to scale up and update their lab
tests.
J&J, which is expected to release late-stage trial data on its
vaccine within days, has laid the groundwork to address troubling
virus changes, Chief Scientific Officer Paul Stoffels told Reuters.
Its trial included sites in South Africa, which should give the
company insight on that variant.
If a change is necessary, Stoffels said J&J likely would add a
second strain into its existing vaccine.
"We are looking at this with a lot of attention," he said.
(Reporting by Julie Steenhuysen in Chicago and Michael Erman in New
York; Editing by Caroline Humer and Bill Berkrot)
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