Treatments, Cures, Vaccines
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Treatment
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Can
Herpes Simplex Be Treated?
Many of us are accustomed to taking antibiotics or other
medications that will rids us of infection quickly. With
virus-caused illnesses, however, a "cure" sometimes
is not possible, and infections can linger for long periods.
Herpes simplex virus has a complicated life cycle that enables
it to persist within the body.
The virus can be attacked, however, with medications called
antiviral drugs. While these can't rid the body of HSV, they
help many people with herpes control the infection and keep
symptoms to a minimum. Antiviral drugs can be taken daily in
small doses to prevent herpes symptoms or can be taken in
larger doses when signs and symptoms appear.
For many years, people diagnosed with genital herpes had to
cope with recurrent symptoms without the benefit of any
medications able to target herpes itself. Beginning in 1985,
however, the advent of antiviral medication in pills,
capsules, or liquid formulations gave patients new options for
gaining a measure of control over the infection. Today, a
decade later, therapeutic options have expanded yet again,
with two new antiviral agents reaching the market. Anyone
whose quality of life is significantly affected by genital
herpes should talk with a doctor about medication to control
outbreaks and minimize the discomfort.
Treatment Regimens
Anti-herpes medication can help to control the infection in
one of three ways:
First
episode: A 10-day course of medication can dramatically lessen
the severity of a first episode. With medication, sores heal
faster, other symptoms such as swollen glands are reduced, and
viral shedding is ended more quickly.
Episodic Therapy: Taken at the first warning sign of an
outbreak, medication can help to shorten the duration of
symptoms and speed healing of sores. Relief is not as dramatic
as in first episodes, however. Most likely to benefit from
episodic therapy are people who have severe or prolonged
recurrences and those who experience prodrome. Gains are much
greater if therapy is started before herpes lesions appear. In
some cases, the prompt use of medication during prodrome will
abort the episode before herpes lesions form. Episodic therapy
is most effective when patients have medication on hand and
can initiate treatment themselves.
Suppressive Therapy: In order to lessen the chance of
recurrences or avert them altogether, patients can take a
small dose of antiviral medication every day for long periods
of time. Patients on the suppressive regimen usually
experience a dramatic reduction in the frequency of symptoms,
and in one five-year study, 20 percent of patients had no
recurrences at all. Overall in this study, the average number
of outbreaks dropped from 13 to fewer than two per year by the
end of the first year and one per year by the end of the fifth
year. (Many physicians will interrupt suppressive therapy at
12-month intervals to re-evaluate the patient's need for
medication.)
In addition, recent research suggests that suppressive therapy
brings a 95% reduction in the number of days per year on which
sub clinical viral shedding occurs and poses a risk of
transmission. Whether suppressive therapy alone can prevent
transmission, however, is still a matter of study, and people
on suppression are still advised to use other precautions as
well.
The Medications
Acyclovir, sold under the brand name Zovirax(R) and now
available as a generic, has been the herpes drug of choice for
over a decade. Acyclovir disrupts the process by which the
virus makes copies of itself and spreads to new cells. Taken
by mouth several times a day ("acute therapy"), it
dramatically reduces the duration and severity of symptoms
during first episodes and can hasten healing during
recurrences as well if taken during prodrome. As mentioned
earlier, acyclovir also can be used on a twice-daily basis for
months at a time to prevent recurrences, a regimen called
"suppressive therapy."
Valaciclovir, a prescription drug sold as Valtrex(R), is a new
compound that uses acyclovir as its active ingredient but is
better absorbed by the body than the original formula. The
major advantage of this improved absorption is less frequent
dosing--twice daily for episodic therapy. Valtrex is approved
for use in treating recurrent genital herpes and will likely
be approved as well for first episodes and for suppressive
therapy.
Famciclovir, a prescription drug sold as Famvir (R), works by
a mode of action similar to acyclovir's but persists for
longer periods within the body, thereby requiring less
frequent dosing (twice daily for episodic therapy). Like
valaciclovir, it is approved for use in treating recurrent
genital herpes and will likely be approved as well for first
episodes and for suppressive therapy.
Safety Concerns
Acyclovir has been used by more than 30 million individuals in
96 countries and has an outstanding safety record. Large
numbers of people have taken it continuously for six or more
years, also without serious adverse effects. Acyclovir is even
being studied in pregnant women, although the drug is not yet
licensed for use in pregnancy outside formal research trials.
The Acyclovir in Pregnancy Registry, started over ten years
ago, has shown no rise in birth defects or any increase in
other problems to date. The newer prodrugs valaciclovir and
famciclovir have similar safety profiles.
Drug-resistant strains of herpes have been identified in
people with weakened immune systems, such as people with AIDS
or those on chemotherapy. It appears that strains of herpes
that are abnormal or deficient in certain enzymes are more
likely to flourish in immune-compromised people, and these
strains also are less likely to respond to therapy with
acyclovir, valaciclovir or famciclovir. On the other hand,
there has been no increase in drug-resistant strains of herpes
in the general population since acyclovir was introduced in
1985, and sensitivity to acyclovir remains high in those
taking the drug even for several years.
Vaccines
In addition to the new antiviral therapies listed here,
researchers are hard at work on vaccines for herpes. The
initial goal of such research is a preventive vaccine that
would protect the vaccine recipient from infection if he or
she were later exposed to herpes. The same type of vaccines
might also provide therapeutic benefit to those already
infected by reducing their number of herpes outbreaks.
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