For the past several
months, pharmaceutical companies and U.S. public health officials have
been busy making and planning for the distribution of millions of doses
of the flu vaccine to protect Americans in the upcoming season.
The
American Academy of Pediatrics released a new recommendation this week
that all children ages 6 months or older be immunized against influenza
as soon as the vaccine is available.
Getting vaccinated each
year remains the best way to protect yourself against the seasonal flu
and lessen the chance you will spread the infection to others.
Despite these efforts,
each year between 3,000 and 49,000 people in the United States and
approximately 500,000 worldwide die from the flu and its complications.
Seasonal flu vaccines reduce the risk of illness in those vaccinated by
about 60%, according to the Centers for Disease Control and Prevention.
Clearly, we need new improved influenza vaccines to provide an even a
better level of protection.
The problem is that for
decades the technologies used to make flu vaccines have remained static.
This fact, coupled with the intrinsic nature of these viruses to
change, has created an untenable situation.
Year-round, scientists,
vaccine manufacturers, and public health officials scramble to protect
the public against both seasonal and potential pandemic influenza
threats, the latter illustrated most recently by the H7N9 bird flu infections in humans occurring in China.
Flu viruses are monitored
continually to identify those most likely to cause human illness. But
it takes at least six months to produce an influenza vaccine once the
targets have been identified; by late February public health officials
must choose three or four virus strains expected to be circulating
widely the following season.
It's a time-consuming
and cumbersome process. These strains usually are grown in eggs (or more
recently, in cells), inactivated and then incorporated into next
season's flu vaccines.
A major drawback of this
strategy is that the circulating flu viruses can evolve significantly
while the vaccine is being prepared and deployed, leaving us with a less
effective vaccine for the threat at hand.
And always looming is the
specter of a novel flu virus emerging to which humans have little or no
immunity, potentially triggering an influenza pandemic -- as happened in
1918, and again in 1957, 1968 and 2009.
Among the two dozen
vaccine-preventable diseases, including measles, mumps, polio, smallpox
and hepatitis, seasonal influenza is the only one for which a new
vaccine is recommended every year. A more efficient approach is long
overdue.
The medical research
community has set its sights on developing a revolutionary type of flu
vaccine, one to protect against a broad spectrum of flu viruses -- a
so-called universal influenza vaccine. Experiments in animals and early
phase clinical trials in humans indicate that this concept of broad
protection is entirely feasible.
Traditional flu vaccines
target regions in the head of a protein found on the surface of the
virus, regions readily seen by the immune system but prone to mutations
as the viruses carelessly reproduce themselves.
In contrast, the new
vaccine may target more stable regions of the influenza protein found in
the stem, somewhat hidden from the immune system by other molecules
nearby, that rarely vary from virus to virus.
Optimally, a universal
flu vaccine would protect against both seasonal and potential pandemic
flu viruses and provide long-lasting protection so it would be given
just once or in a series of boosts, like the measles vaccine.
Realistically, however, a
universal flu vaccine likely will be developed in incremental steps
rather than in one giant leap -- a flu vaccine given once every ten
years, like a tetanus shot, for example, or one shot that offers
cross-protection against a subgroup of related influenza viruses is more
likely in the short term.
A universal flu vaccine
would modernize our prevention strategy, lower health care costs, and
bring influenza vaccines more in line with other licensed vaccines.
Much work needs to be
done before this goal is reached, and in the meantime, getting an annual
flu shot in its current form is still the best protection for everyone.
But in 2013, 80 years after scientists discovered that influenza is
caused by a virus, we all can be encouraged that research on a
transformative approach to influenza prevention is moving ahead.
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