SCIENCE science.org 15 APRIL 2022 • VOL 376 ISSUE 6590 227PHOTO: ZOU ZHENG/XINHUA/GETTY IMAGES
S
cientists in more than 20 countries, on
every continent save Antarctica, have
started to gather data for the largest
ever vaccine safety project. Members
of the effort, called the Global Vac-
cine Data Network (GVDN), fruitlessly
sought funding after conceiving the project
more than 10 years ago. But the mass vac-
cinations during the COVID-19 pandemic
breathed new life into the project. With
the ability to draw on data from more than
250 million people, the network will investi-
gate rare complications linked to COVID-
vaccines in hopes of improving prediction,
treatment, and potentially prevention of
these side effects.
“You really need global data in order to
understand” rare vaccine side effects, says
Gregory Poland, a vaccinologist at the Mayo
Clinic. Poland, who’s not involved in GVDN,
himself developed severe tinnitus about
90 minutes after his second vaccine dose,
which he suspects is related to the shot.
Studying potential vaccine complications “is
a very neglected area,” he says.
Bruce Carleton, a clinical pharmaco-
logist at the University of British Colum-bia, Vancouver, and head of the GVDN
genomics effort, draws an analogy to air
travel safety. There, improvements often
came after ultrarare crashes. Airplanes,
Carleton says, were shored up by “learn-
ing from those events, not denying them.”
With billions of doses of COVID-19 vac-
cines administered, it’s clear the vaccines
are “very safe for most people,” he contin-
ues. At the same time, “There probably are
patients that may, in fact, suffer harm.”
Doing this research comes with steep
scientific hurdles, among them the rarity
of serious problems. The largest vaccine
studies have included about 1 million peo-
ple, and even that can be too small to nail
down side effects. “If you had something
that happened normally to one in 100,
people, and you wanted to see if the vac-
cine doubled the risk, you’d need a study
with about 4 million people,” says Helen
Petousis-Harris, a vaccinologist at the
University of Auckland who jointly heads
GVDN with Steven Black, a pediatric infec-
tious disease specialist formerly at Cincin-
nati Children’s Hospital.
The idea for GVDN came to Black
around 2009, when the H1N1 flu pandemic
hit and a mass vaccination campaign be-gan. Some countries detected an increased
risk of narcolepsy from the vaccine, called
Pandemrix, but others did not. The vari-
ability might have reflected differences
in vaccine surveillance, which varies geo-
graphically, with some countries relying
on passive reporting and others combing
through health records for patterns. Or,
scientists came to suspect, the immune
response to vaccination might somehow
have interacted with flu infection to trig-
ger the narcolepsy. Black thought consis-
tent data could help solve such mysteries.
He set out to globalize vaccine safety re-
search. Funding, however, was nowhere to
be found. Then in 2019, the Bill & Melinda
Gates Foundation offered seed money for a
meeting. About 60 vaccine safety specialists
descended on a lakeside village in France and
GVDN was born. The network got a jump-
start with support from Petousis-Harris’s
university and Auckland UniServices Ltd., a
nonprofit owned by the institution.
Carleton and Daniel Salmon, a vaccine
safety researcher at Johns Hopkins Univer-
sity, conjured up its first project: a study
of the potential risk of Guillain-Barré syn-
drome, a rare neurologic condition, from
flu vaccines. In early February 2020, just asBy Jennifer Couzin-FrankelCOVID-Global project gears up to study vaccine safety
Pandemic propels international efforts to understand incidence of rare side effects
IN DEPTH
Mass vaccination efforts for COVID-19, like this one in Toronto, gave new life to a vaccine safety project that could cover hundreds of millions of people worldwide.