Contents - Winter 2009
Vol. 2 No. 1
Saving Young Lives Through Vaccine Research
Women have their children vaccinated
against measles in the Babile district
of Ethiopia during an EOS campaign
organized by UNICEF and funded by
the Global Fund. Photo courtesy of the
Bill & Melinda Gates Foundation/Liz Gilbert.
By Matt Barron
Before there was a vaccine, whooping cough was one of the
most common North American childhood diseases and a
major cause of childhood deaths.
The incidence of this highly contagious respiratory infection—it
gets its name from the high-pitched intake of breath that sounds
like “whoop”—declined with immunization that began in the
1940s.
Today whooping cough is again on
the rise, with a few thousand cases
occurring in Canada every year and
mainly affecting young adults and
older children.
Why the resurgence? Protection
provided by vaccines tends to fade
over time. And the bacteria that
triggers the disease, Bordetella
pertussis, is changing.
“Back when these vaccines were developed, it was believed
that they would provide life-time immunity and that whooping
cough was just a childhood disease. With today’s research, we now
know differently,” says Dr. Volker Gerdts, scientific manager of a
University of Saskatchewan vaccine research project.
“We need to raise the level of immunity in all of us again, and
that means vaccination for both children and adults.”
Globally there are more than 40 million cases of whooping
cough and up to 300,000 deaths each year, with children in
developing countries most at risk. A child in a developing country
is 10 times more likely to die of a vaccine-preventable disease such
as whooping cough than a child from an industrialized country.
The problem is that most existing vaccines require a series
of immunizations or “booster shots”—a major challenge in
developing countries where it is often difficult for families to
return many times to a distant medical clinic for booster shots.
The whooping cough immunization
process requires the first shot at two months
of age and the second at four months. The
newborn isn’t protected until the third
shot—at six months old, and requires yet
another additional immunization after that. This leaves infants vulnerable to the disease
for the first six months of their lives—a
picture window of opportunity for the
bacteria to attack.
But what if scientists could find a way
to induce a long-lasting immune response
against whooping cough with just a single
shot of vaccine? What if
vaccines could be delivered
straight to the respiratory
tract’s mucosal surfaces
(where most disease-causing
organisms enter) without the
use of needles at all?
That is exactly what Gerdts
and his team at the
U of S
Vaccine and Infectious
Disease Organization (VIDO)
are working to develop.
In 2006, the team was
awarded US $5.6 million
from the Bill & Melinda
Gates Foundation through its
Grand Challenges in Global
Initiative, along with funding
from the Canadian Institutes
of Health Research. The
team is spearheaded by U
of S professor emeritus and
former VIDO director Lorne
Babiuk.
The new “single-dose
vaccine” currently being
tested contains adjuvants—
vaccine components designed
to improve the immune
response in the newborn. By
developing novel adjuvants,
the team hopes to improve
the newborn’s immune
response and reduce the number of
immunizations required to a single shot.
The new vaccine would be administered
nasally through a painless spray rather
than a painful needle shot in the arm. A
nasal inhaler would not only be easier to
use, but also more effective in combating
the disease—both its tenaciousness in
the developing world and its resurgence
elsewhere.
With research partners at the University
of British Columbia, Dalhousie University
and Korea’s International Vaccine Institute,
the VIDO team is testing new vaccine
formulations in animal models. Human
trials of the vaccine are expected in five to
seven years.
“The general strategy VIDO is pursuing is
really innovative,” says Dr. David Scheifele,
a renowned specialist in pediatric infectious
disease at the Vaccine Evaluation Centre at
B.C. Children’s Hospital.
Vaccine research team at the U of S Vaccine and Infectious Disease Organization. Photo by Debra Marshall for the U of S.
“It is one of the grand challenges to better
protect the airway against diseases like
pertussis, to do it in the young infant, and
to potentially do it with fewer doses than at
present. Put all of those things together and
this will be an extraordinary success.”
Besides its potential for effectiveness
with just a single dose, the vaccine’s big
advantage over injected vaccines, which
do battle by creating systemic immune
responses, the team’s new vaccine would
double the immune system’s weaponry. It
would not only produce systemic immunity,
but also trigger an immune response
right at the site of infection—the mucosal
membranes where the B. pertussis bacteria
invade the airways.
“Having the mucosal response can be
more effective than an injected vaccine,”
Gerdts says. “An injected vaccine typically
gives you good systemic immunity. But if
you immunize via the mucosal surfaces,
you will get both systemic and mucosal
immunity. This is much more effective in
preventing disease.”
The VIDO team hopes the single-dose
vaccine can be multi-purposed to combat
other threats that still exist for infants.
For example, Sylvia van Drunen Littel-van
den Hurk, a senior VIDO researcher, has
been exploring the vaccine’s effectiveness
in tackling respiratory syncytial virus, the
most common cause of pneumonia and
bronchiolitis in young children under one
year of age.
Looking ahead, Gerdts
is now exploring a second
vaccination option for
preventing a range of
childhood diseases—the
possibility of vaccinating
the fetus during pregnancy
to induce immune
responses that would later
protect the infant against
early childhood infections.
He recently received a
second Gates Foundation
grant to carry out the
research—this time through
its Grand Challenges
Explorations initiative, a
program that challenges
health researchers to pursue
ideas which have shown
promise in improving world
health.
Marina Facci, one of five
graduate students on the
team, says a single-dose
vaccine administered
through a nasal
inhaler would facilitate
immunization compliance
worldwide, increasing
the likelihood that babies
in both developing and
developed countries would be adequately
protected against infection by B. pertussis.
Having been born in Zambia and grown
up in South Africa, Facci has seen many
places where countries that are too poor to
provide adequate access to health care for
their citizens.
“Being part of a project funded by the
Gates Foundation is a great opportunity
to contribute in some way to people who
might not have access to the health system
we have here in Canada,” she says.
Click here for more information about U of S research on this topic.
