U.S. needs more effective flu shots, experts say | News
(USA TODAY) -- In the midst of an early flu season, public health officials are
urging unvaccinated people to get a flu shot, as the best step they can
take to protect both themselves and their families.
Centers for Disease Control and Prevention also acknowledged Friday that
influenza vaccines, on average, are only about 62% effective. In the
past, the CDC had estimated that flu shots were 70% to 90% effective.
"There is a growing consensus among the public health communities that
we need better influenza vaccines," says Michael Osterholm, director of
the Center for Infectious Disease Research and Policy. "We're operating
largely in the 1950s for our flu technology."
Osterholm last year published an influential analysis in The Lancet
showing that, according to very rigorous standards, evidence indicated
that flu shots were less effective than commonly reported. For children
and seniors over age 65, there was no rigorous data showing their
efficacy at all.
One subset of patients does get high protection
from flu vaccines, Osterholm found. The intranasal flu vaccine, sold as
FluMist, protects 83% of children under 8. There's mixed evidence about
how well FluMist protects adults over 60, and a lack of evidence on its
effect in people ages 8 to 59.
In general, "The flu vaccine is a
good vaccine, but not a great vaccine," says William Schaffner, a
professor at Vanderbilt University School of Medicine.
says he strongly believes people should get yearly flu vaccines, given
their good safety record. And he says "moderate" protection is better
than no protection at all.
But drug companies have felt little
pressure to make truly "game-changing" vaccines, Osterholm says, because
experts and the public have believed that current shots are adequate.
"The No. 1 deterrent to getting new flu vaccines is the perception that
the current ones are good enough," says Osterholm, also a professor at
the University of Minnesota School of Public Health.
relatively low efficacy, the flu shot today doesn't have much power to
produce true "herd immunity," Osterholm says. Herd immunity is achieved
when enough people are immunized with an effective vaccine that the
community's viral load drops, protecting even the unvaccinated.
Joseph Bresee, chief of the CDC's epidemiology and prevention branch
in its influenza division, said Friday that "there's lot of research
going on toward improving vaccines," noting that "the goal is to create a
vaccine that you don't have to give every year that works better."
Today, people need to be revaccinated every year against the flu.
That's because the influenza virus is constantly changing. Virologists
try to predict which viruses will be in circulation in the coming
season, hoping to get a good "match" between the viruses in the
community and the viral strains used in the vaccine.
A "game-changing" vaccine would be very different.
Such a vaccine would produce immunity by including parts of the
influenza virus that don't change from year to year, and which are
common among many strains of virus, Osterholm says. These vaccines
should also protect people for a decade or more, stimulating the immune
system to recognize flu viruses that it hasn't encountered for a long
In a 2011 interview with USA TODAY, National Institutes of
Health director Francis Collins said he was "guardedly optimistic" that a
"universal" flu shot could be developed within about five years.
One such game-changing vaccine is being tested in the USA in an early
phase one trial - the smallest and most preliminary type of human study -
"It's clearly the holy grail," Schaffner says.
But the USA should be doing more to lead the way, Osterholm says.
Most vaccines in development today make only minor improvements,
Osterholm says, relying on the same techniques used for decades. These
vaccines produce immunity by using proteins found on a virus' outer
Of the more than 170 influenza vaccines in clinical trials around
the world, all but 13 are made in the traditional way, Osterholm says.
None are supported by the U.S. government, he says.
Developing a next-generation flu vaccine could take 15 years and cost over $1 billion, Osterholm estimates.
Schaffner notes that significant improvements are already being made.
Next year's flu shots should provide slightly broader protection. The
FluMist nasal spray will protect against four viral strains, instead of
the current three. Manufacturers of flu shots are also working to
include four viral strains.
Also, the Food and Drug
Administration in November approved the first flu vaccine made in cell
cultures, rather than chicken eggs. The vaccine, Flucelvax, made by
Novartis, is approved only for adults.
Many European countries
already use cell culture techniques, which allow companies to produce
vaccine far more quickly, Osterholm says.
allows vaccine makers to respond rapidly to "urgent public health
needs, such as a pandemic, within weeks," according to Novartis.
The USA's current system - a six- to nine-month process that relies on
fertilized chicken eggs to grow viruses - is "archaic," says Robert
Glatter, an emergency medicine physician at Lenox Hill Hospital in New
Yet while cell cultures will allow companies to manufacture
vaccines much more quickly, it doesn't make the vaccine any more
effective, Osterholm says.
And Glatter says companies face significant obstacles in developing innovative flu vaccines.
It's "quite difficult for private companies to embark on such an
endeavor, in light of the U.S. government's strict policies toward
approving vaccines," which must undergo rigorous tests for safety,
Drug companies may see little point in developing a
universal vaccine, Glatter says. "If you get a mega-vaccine once every
10 years to prevent the flu, the flu vaccine market would essentially be
down-regulated, with less financial market incentive."
Glatter says 2009's H1N1 pandemic flu suggests that the human body is
capable of producing extremely long-term immunity from influenza. Senior
citizens had relatively low rates of infection during that outbreak,
likely because they were exposed to a similar virus during the 1930s and
1940s, he says.
"The goal is to make a vaccine that can confer
such long-term immunity," Glatter says. "Such a feat would be a real
A broadly protective flu vaccine might save lives
during a pandemic, because many people would already have been
vaccinated, Osterholm says. During the 2009 H1N1 pandemic, manufacturers
required months to develop a matching flu shot.
But a universal
vaccine would have its greatest impact in the developing world,
Schaffner says. Many poor countries can't afford yearly flu shots. Far
more people could be vaccinated if they only had to pay for a shot every
10 years, he says.