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StaphVAX
A
genetically engineered vaccine has been shown to protect against
life-threatening Staphylococcus aureus infections, a major risk
among hospitalized patients. arly results show promise for
lowering nosocomial infection rates.
Permanente Vaccine Study Center in Oakland, California, stated
that "the potential for this vaccine is very exciting. It could
well be a major breakthrough in protecting patients from these
serious infections."The results of the phase 3 testing of the S
aureus polysaccharide conjugate vaccine.
StaphVAX
involved 1,800 patients who were receiving dialysis for end-stage
renal disease and were considered at high risk of infection from
repeated needle punctures. Among patients receiving the vaccine, S
aureus antibody levels peaked at 10 to 14 days, plateaued until
about 40 weeks, and then dropped to baseline as the vaccine lost
its effectiveness. At 40 weeks, 26 patients in the placebo group
had had S aureus infections, compared with 11 in the vaccine
group. This represented a 57% reduction in the infection rate and
was considered statistically significant.
"These patients were at very high risk," Dr Shinefield pointed
out. "The fact that the vaccine prevents infection, rather than
stopping it after it starts, offers new avenues for prophylaxis in
many high-risk situations. This is especially important because of
increasing resistance of bacteria to antibiotics."
A
second trial is now under way to evaluate a booster dose of the
vaccine in 100 of the patients who participated in the first
trial. Also, because the initial trial fell short of its original
goal of showing effectiveness at 54 weeks after vaccination,
the US Food and Drug Administration has requested another phase 3
trial before considering approval.
The
vaccine was created at the National Institutes of Health and is
one of several S aureus vaccines in development. None of the other
products have reached the advanced clinical trial stage at this
time.
Antibodies to Target Biofilm
The bacteria produces the substance when growing a biofilm that
protects them from antibiotics. Scientists are are targeting this
material as a possible vaccine, but natural exposure to the sugar
compound does not result in most people and animals making an
immune response that would protect them from attack by the
bacteria or recurring infections.
Methicillin-resistant Staphyloccus aureus, or MRSA, infections
can range from boils to more severe infections of the bloodstream,
lungs and surgical sites. MRSA is a growing problem worldwide and
can cause life-threatening and disfiguring infections.
The antibody is being manufactured to start tests in humans in
about 12 to 18 months.
“An effective antibody treatment for Staph infections could
have a major benefit for anyone who enters a hospital or works in
the community and is at risk.”
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