12 TIME March 15/March 22, 2021
I
T’S ONE THING TO TEST A VACCINE IN A
controlled study, and another to see it in action
in the real world. Since the fi rst COVID-
vaccines were approved at the end of 2020, more
than 250 million people around the world have been
vaccinated, and public-health experts are starting to
see how the shots are faring when put to the ultimate
test. That information is especially critical as new,
more infectious versions of SARS-CoV-2 are starting to
dominate new cases in certain countries—such as the
U.K. and South Africa— raising concerns among both the
public and health leaders over whether existing vaccines
will work against these viral variants.
So far, studies show that the vaccines are doing
what they should. In two large data reviews—one con-
ducted in Israel, where most people have been vacci-
nated with a shot developed by Pfi zer-BioNTech, and
the other in Scotland, where people have been get-
ting either the Pfi zer-BioNTech vaccine or one from
AstraZeneca— scientists found that people who have been
vaccinated are less likely to get sick with COVID-19 or
need hospitalization for the disease. The shot
appears to be especially eff ective at lowering
risk of severe illness. In the Israel- based study,
scientists even found hints that the vaccine
could protect people from getting infected in the
fi rst place, an important factor in shutting down
spread of the virus.
More good news: there isn’t strong evidence
yet that the new viral variants have actually fi g-
ured out how to break through the protection
provided by the vaccines. Neither the Israel-
nor the Scotland- based research specifi cally
tracked the vaccines’ eff ectiveness against new
variants, but in Israel, one of the variants be-
came more dominant during the study, and
the scientists note that the overall drop in hos-
pitalizations suggests the vaccine was likely
eff ective against diff erent mutant strains.
Johnson & Johnson’s Janssen group, which
received emergency- use authorization from
the U.S. Food and Drug Administration on
Feb. 27 for its vaccine, provided the most re-
cent encouraging data: the company’s global
study of its single-dose shot included par-
ticipants in South Africa, where nearly all
new infections can now be traced to one of
the new variants, and found that the vaccine
was 57% eff ective in protecting people from
severe COVID-19 illness in the country. (The
FDA’s threshold for granting emergency use
to COVID-19 vaccines is 50%.) Studies by the manufac-
turers of the other two authorized vaccines in the U.S.—
Pfi zer-BioNTech and Moderna—showed similarly suf-
fi cient protection, although both also reported slightly
lower levels of immune antibodies generated against one
of the variant viruses.
What’s clear is that while the vaccines remain eff ec-
tive, vaccinemakers and public-health offi cials have to
remain vigilant. SARS-CoV-2 won’t sit still, and more
variants are inevitable, given that viruses are trained to
morph and fi nd more effi cient ways to infect new hosts.ANTICIPATING THIS, PFIZER-BIONTECH and Moderna
have both launched studies in which people who have
already received a full two-shot regimen will be given
a third dose. The goal is to see if boosting with an ad-
ditional injection will bring up their immune responses
against major viral variants.
In case that’s not enough, each company has also
designed new vaccines against the variant from
South Africa. To make their original vaccines, both used
mRNA technology, which involves injecting genetic mate-
rial from the virus into the body, where it produces a viral
protein that trains the immune cells to target and attack
the actual virus later on. To create new vaccines against
the variant strain, scientists simply swapped out the origi-
nal genetic code for one including the variant’s mutations,
in the same way that the fl u shot is modifi ed each season
to target new versions of infl uenza. “We always
want to be one step ahead of the virus,” says Mikael
Dolsten, chief scientifi c offi cer at Pfi zer. “We ex-
pect that the antibody levels may rise against cur-
rent variants to strengthen protection.”
Janssen, too, is looking to amplify the protec-
tion provided by its vaccine. Its team is testing
whether adding a second dose to the current one-
dose regimen could generate a stronger immune
response; it expects results in several months.
All this could be a dry run for how we manage
COVID-19 in coming years. If the virus remains
stubbornly resilient, mutating to evade the
protection from vaccines and drug therapies,
vaccinemakers could be scanning for new variants
and tweaking vaccines every year or so, just as
they do the fl u shot. If the protection provided by
the vaccines creates enough of a barrier against
SARS-CoV-2, however, the virus may fi nd itself
without enough people to infect and peter out.
For now, the vaccines at least appear to be
lowering the tremendous burden of COVID-
disease on strained health care systems. Public-
health experts are hoping quick and complete
vaccination programs will lighten the responsibil-
ity even further and eventually stop the virus in its
tracks. They won’t know for sure if that’s possible
until a greater proportion of the world’s popula-
tion is vaccinated, and they can track how the
virus reacts to that growing wall of immunity. □TheBrief Opener
‘We always
want to be one
step ahead of
the virus.’
MIKAEL DOLSTEN,
chief scientifi c
offi cer at Pfi zerHEALTH
Vaccines vs.
viral variants
By Alice Park