he could be sure, he replied that the
effectiveness of any vaccine could be
assessed not only by collecting epide-
miological data but also by looking for
antibodies. This is not always the case:
several prototype vaccines, including
one for H.I.V., have produced antibod-
ies without protecting against infection.
Logunov recalled reading about the
new virus in China at the end of 2019,
but it wasn’t until mid-February, 2020,
when he took part in a two-day W.H.O.
forum in Geneva on COVID-19, that he
understood the scale of the crisis. “That’s
when I knew the world wasn’t going to
cope,” he said. The Gamaleya scientists’
familiarity with adenovirus vectors al-
lowed them to move quickly. Logunov,
who worked with some sixty research-
ers at Gamaleya on the COVID-19 vac-
cine, told me, “We didn’t face the ques-
tion of which approach to use.” Dis-
cussing the strengths of the adenovirus
platform, he said, “I would compare it
to a rocket. This launch vehicle can de-
liver satellites, equipment, people—it
carries whatever cargo you give it.” Lo-
gunov rejected the suggestion that his
team’s vector-based method was partic-
ularly pioneering, positioning his own
laboratory and Sputnik V as part of the
global scientific mainstream. “This is
not a story of some great breakthrough
but, rather, of reaching for a quick solu-
tion while a pandemic unfolds,” he said.
At Gamaleya, I also paid a visit to
the laboratory of Vladimir Gushchin,
who oversaw the sequencing of the vi-
rus’s genetic code. Chinese scientists had
published the SARS-CoV-2 genome se-
quence last January, but the Gamaleya
researchers needed their own live viral
strain in order to create an infectious
model of the pathogen for their exper-
iments. Gushchin described how, for
several days in March, he and others
from his lab had searched for a usable
sample of the virus, rushing back and
forth between Gamaleya and a hospital
in Kommunarka, on the outskirts of
Moscow, which had been designated
early on to treat COVID-19 patients—
mostly travellers who had contracted the
virus in Europe. The strain they even-
tually used to test Sputnik V came from
a Russian citizen who was known to
have been in Rome on March 15th. He
was already sick when he landed at Mos-
cow’s Sheremetyevo Airport, and was
swiftly taken to Kommunarka for treat-
ment. Gushchin and his team picked up
the patient’s swab on March 17th.
When I walked through Gushchin’s
lab, he showed me the genetic sequencer
that had been used to map the original
sample, a plastic box not much larger
than a laser printer. “We understood that
this was very valuable material,” Gu-
shchin told me, “but also that there was
so much we didn’t know—how to cul-
tivate the virus, what its life span might
be, how likely you are to be infected
while working with it.”
The main complication in using anadenovirus vector is the possibility that
the patient might already have—or
might develop, after the first of two
consecutive inoculations—immunity to
the vector. If a person’s body recognizes
the vector as a foreign object that needs
to be destroyed, it will reject the ge-
netic cargo as well, rendering the vac-
cine less effective. Manufacturers have
found ways around these issues in their
COVID-19 vaccines. Johnson & John-
son uses adenovirus-26, a rare variant
of cold virus to which most recipients
would be unlikely to mount a robust
immune response. The Oxford-Astra-
Zeneca vaccine uses an adenovirus strain
that infects chimpanzees, and to which
humans presumably do not have preëx-
isting immunity.
The researchers at Gamaleya de-
cided to use two separate vectors, as
they had done with their Ebola and
MERS vaccines. In the first dose, the
vector would be adenovirus-26; for the
second shot, which is meant to help in-
duce long-lasting immunity by activat-
ing T cells, they chose adenovirus-5, a
more common strain. Jerome Kim, the
director of the International Vaccine
Institute, told me that the two-vector
approach, known to scientists as “het-
erologous prime boosting,” is grounded
in sound theory. “It’s a way to confuse
the immune system so that it focusses
on the COVID-19 protein,” he said. But,
he added, “we need to see the data be-
fore we can say whether this particular
vaccine is ready for prime time.” Chu-
makov expressed similar reservations,
saying that, until the long-term efficacy
of the various vectors has been proved,
the arguments for and against each ap-
proach remain “entirely theoretical, and
thus equally valid or bogus.”
In assembling the vaccine, Gama-
leya’s scientists used an enzyme to stitch
together the vectors’ DNA and the gene
that codes for the spike protein of SARS-
CoV-2. In less than two weeks, and even
before Moscow went into lockdown, a
prototype vaccine was ready. Logunov
showed me his laboratory’s vivarium, a
small room with dozens of plastic cages
of live mice stacked nearly to the ceil-
ing. In March, researchers vaccinated
mice and analyzed their blood for an
immune response. Next came hamsters
and guinea pigs, followed by macaques
“Enjoy that body while you can. It ain’t gonna last.” and marmosets. All produced high lev-