By Peter Loftus
Moderna Inc. said its Covid-19 vaccine appeared to protect
against emerging variants of the coronavirus in laboratory tests,
but as a precaution it would test whether a booster shot improves
immune responses and develop a new vaccine targeting the strain
first identified in South Africa.
The company said Monday its vaccine produced immune-system
agents known as neutralizing antibodies that worked against the
emerging virus variants tested, including strains first evident in
the U.K. and South Africa.
That means the Moderna vaccine likely still protects against the
emerging strains, but a weaker response to the South Africa variant
suggests the hazards of a virus that could mutate in significant
ways while countries race to vaccinate against it.
The new strains appear to spread more easily from person to
person, and there are signs that the U.K. variant is more deadly
than earlier forms of the virus. The strains appear to be spreading
around the world, prompting U.S. health authorities to warn the
variant first detected in the U.K. could become dominant by
The variant first found in South Africa hasn't been detected in
the U.S., Anthony Fauci, the nation's top-infectious disease
expert, said Sunday. To curb the spread of new strains into the
U.S., President Biden on Monday restricted travel from South Africa
and re-established a ban on most travel into the U.S. from Europe,
the U.K. and Brazil.
Since the new strains emerged, vaccine makers have been saying
they think their vaccines will still provide protection. Moderna's
announcement supports research by outside scientists indicating the
protection against the strain identified in South Africa, in
particular, may not be as strong though still effective.
Pfizer Inc. and BioNTech, which make the only other Covid-19
vaccine authorized for use in the U.S., are continuing to run lab
studies of their vaccine against new variants, a Pfizer spokeswoman
Moderna said its vaccine induced production of neutralizing
antibodies against the strain first identified in the U.K., known
as B.1.1.7, at levels comparable to prior variants. Yet
neutralization decreased sharply in the case of the strain in South
Africa, known as B.1.351, according to a paper posted on the
preprint server bioRxiv. Researchers from both Moderna and the
National Institutes of Health's Vaccine Research Center conducted
the analyses. The paper hasn't yet gone through the standard
Even with the decrease, Moderna said, the vaccine-induced
antibody response to the B.1.351 variant remained above levels
deemed protective. The company said it expects its standard
two-dose vaccine to guard against the emerging viral strains to
It will test, however, whether adding a booster dose of its
original vaccine can bolster antibody levels against emerging
strains. The company is also developing a new version of the
vaccine that targets more specifically the mutations in the South
Africa variant and will test whether given as a booster shot it
induces a better immune response.
The company plans to start within a couple of months a Phase 1
study of the booster shot aimed at the South African variant.
"In the event that this virus continues to mutate in this
direction, and a year from now is still circulating in some way, we
think it's prudent that we have tools like a booster vaccine to
address that," Moderna President Stephen Hoge said in an
Moderna said it expects that its booster shot -- whether for the
original vaccine or one targeting the variant first identified in
South Africa -- could be given in combination with vaccines from
The coronavirus variant in South Africa has several mutations in
its so-called spike protein, which is found on the surface of the
virus. Moderna's vaccine and most others are designed around the
spike protein or its genetic code as a way to induce an immune
response to the virus; and so, mutations in the protein have the
potential to hurt the performance of a vaccine.
The modified vaccine Moderna is developing is designed to
trigger the production of the spike protein specific to the South
African variant, which in turn induces an immune response.
The company believes it can quickly design and manufacture the
modified vaccine and have it ready for human testing over a shorter
span than was the case with the original vaccine. Last year, it
shipped the first batch for testing about six weeks after selecting
the initial design, and the first human study started within two
"I believe we should be able to go even faster now," Chief
Executive Stephane Bancel said last week during an interview for
the WSJ Executive Membership Series. "If in the future we encounter
a mutation that requires a new vaccine, we could very quickly, in a
matter of a month or so, get a new vaccine out."
Mr. Bancel said he didn't think regulators would require such a
vaccine to go through the full series of human studies since it
would have the same underlying gene-based technology as the
Moderna's move points to the potential that Covid-19 vaccines
will have to be modified -- and possibly given to people as repeat
doses -- to address a changing virus.
"We may have to begin thinking about this like influenza
vaccines and start rolling out regular annual vaccinations" with
modified vaccines that target different strains, said Peter Hotez,
dean of the National School of Tropical Medicine at Baylor College
of Medicine in Texas.
Last week, Pfizer and BioNTech said their vaccine -- which uses
a gene-based technology like that of Moderna's shot -- appeared to
be protective against the U.K. virus strain, based on lab
"The virus is evolving and it's getting fitter and better at
what it needs to do," said Dr. Hoge, Moderna's president. "And both
the South African and the U.K. strains, we're seeing clearly
increases in transmission, and the potential for infectivity."
Moderna shares were ahead 11% at $145.23 in afternoon trading
--Jared S. Hopkins contributed to this article.
Write to Peter Loftus at firstname.lastname@example.org
(END) Dow Jones Newswires
January 25, 2021 15:40 ET (20:40 GMT)
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