Moderna, Pfizer test vaccine strategies against new variants
(CNN)Vaccine makers Pfizer and Moderna are trying to get out ahead of some of the new coronavirus variants that are causing concern around the world.
Although
there's no evidence people immunized with either vaccine have less
protection against the variants, both companies said they have started
looking at ways to account for evolving mutations.
Especially
worrying is the B.1.351 variant first seen in South Africa. It carries a
mutation that helps it elude the body's immune response to infection.
The B.1.1.7 variant first seen in the UK is also causing concern, as its
mutations appear to make it more transmissible, so it spreads better,
and it may also cause more severe disease.
Researchers are also finding variants across the US that have developed mutations that help them evade the immune system.
Pfizer
and its partner BioNTech said Thursday they have begun to test how well
adding a third dose of their authorized vaccine might protect against
new variants.
The
study will look at the safety and immune response of a booster dose in
up to 144 participants from the earlier Phase 1 trial in the US,
including a subset of older adults up to age 85. It will also involve
testing how well their antibodies are able to neutralize "strains of
interest" in the lab, the companies said.
Volunteers
would receive a third dose between 6 to 12 months after their earlier
two doses. The dosage would be identical to what's currently authorized:
30 micrograms.
"This
booster study is critical to understanding the safety of a third dose
and efficacy against circulating strains," Pfizer CEO Dr. Albert Bourla
said in a statement.
Separately,
Pfizer and BioNTech are also "in ongoing discussions with regulatory
authorities" about potentially testing a vaccine modified to protect
against concerning variants in a Phase 1/2 study.
However,
Bourla noted the companies haven't yet seen compelling evidence that
variants are resistant to its vaccine, though they are taking steps to
be prepared.
Moderna
said late Wednesday it has produced an updated version of its Covid-19
vaccine to help it combat the B.1.351 variant first seen in South
Africa. Initial doses have been shipped to the National Institutes of
Health for a clinical study.
The
new vaccine, called mRNA-1273.351, will be evaluated as a booster shot
for people who have already been vaccinated against coronavirus and as a
primary vaccine for people who haven't had coronavirus and have yet to
be vaccinated.
Moderna
said it will also evaluate a "multivalent" booster shot that combines
the new vaccine formulation with the current vaccine.
Additionally,
the company said it has begun to test whether a third, lower dose of
its current Covid-19 vaccine can increase immunity against coronavirus
variants of concern, with some study participants already getting third
doses.
"We
are moving quickly to test updates to the vaccines that address
emerging variants of the virus in the clinic. Moderna is committed to
making as many updates to our vaccine as necessary until the pandemic is
under control. We hope to demonstrate that booster doses, if necessary,
can be done at lower dose levels, which will allow us to provide many
more doses to the global community in late 2021 and 2022 if necessary,"
Stephane Bancel, Moderna's CEO, said in a statement.
Moderna
did not say how long it expects the studies to take, or when the new
vaccine would be available, if authorized. The current vaccine calls two
100 microgram doses spaced about a month apart. The new booster doses
are being evaluated at half that level and lower.
On
Monday, the US Food and Drug Administration announced new guidelines
that would streamline and speed the process of updating vaccines to
target variants. An agency official estimated this could involve a
several hundred individuals and take a few months.
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"It's
going to be on the order of a few hundred individuals in terms of size
and we'd expect that that might take a few months," Dr. Peter Marks,
director of the FDA's Center for Biologics Evaluation and Research, said
during a call with reporters on Monday.
Both
Moderna's and Pfizer's vaccine use a new technology using messenger RNA
or mRNA that simply requires a genetic code. The design is meant to
make the vaccines easy to update quickly, without the months of
preparation needed to change an influenza vaccine, for example.
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