Know
H1N1 Flu (Swine Flu) – Its Symptoms,
Prevention and
Treatment
What is novel H1N1 (swine flu)?
Novel H1N1 (referred to as “swine flu” early
on) is a new influenza virus causing illness
in people. This new virus was first detected
in people in the United States in April
2009. This virus is spreading from
person-to-person worldwide, probably in much
the same way that regular seasonal influenza
viruses spread. On June 11, 2009, the (WHO)
signaled that a pandemic of novel H1N1 flu
was underway.
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Why is novel H1N1 virus
sometimes called “swine flu”?
This virus was originally
referred to as “swine flu”
because laboratory testing
showed that many of the genes in
this new virus were very similar
to influenza viruses that
normally occur in pigs (swine)
in North America. But further
study has shown that this new
virus is very different from
what normally circulates in
North American pigs. It has two
genes from flu viruses that
normally circulate in pigs in
Europe and Asia and bird (avian)
genes and human genes.
Scientists call this a
"quadruple reassortant" virus. |
What are the signs and symptoms of this
virus in people?
The symptoms of novel H1N1 flu virus in
people include fever, cough, sore throat,
runny or stuffy nose, body aches, headache,
chills and fatigue. A significant number of
people who have been infected with this
virus also have reported diarrhea and
vomiting. Severe illnesses and death has
occurred as a result of illness associated
with this virus.
How severe is illness associated with novel
H1N1 flu virus?
Illness with the new H1N1 virus has ranged
from mild to severe. While most people who
have been sick have recovered without
needing medical treatment, hospitalizations
and deaths from infection with this virus
have occurred.
In seasonal flu, certain people are at “high
risk” of serious complications. This
includes people 65 years and older, children
younger than five years old, pregnant women,
and people of any age with certain chronic
medical conditions. About 70 percent of
people who have been hospitalized with this
novel H1N1 virus have had one or more
medical conditions previously recognized as
placing people at “high risk” of serious
seasonal flu-related complications. This
includes pregnancy, diabetes, heart disease,
asthma and kidney disease.
One thing that appears to be different from
seasonal influenza is that adults older than
64 years do not yet appear to be at
increased risk of novel H1N1-related
complications thus far. CDC laboratory
studies have shown that children and few
adults younger than 60 years old do not have
existing antibody to novel H1N1 flu virus;
however, about one-third of adults older
than 60 may have antibodies against this
virus. It is unknown how much, if any,
protection may be afforded against novel
H1N1 flu by any existing antibody.
Treatment of Swine Flu
Antiviral drugs are prescription medicines
(pills, liquid or an inhaler) with activity
against influenza viruses, including swine
influenza viruses. Antiviral drugs can be
used to treat swine flu or to prevent
infection with swine flu viruses. These
medications must be prescribed by a health
care professional. Influenza antiviral drugs
only work against influenza viruses -- they
will not help treat or prevent symptoms
caused by infection from other viruses that
can cause symptoms similar to the flu.
There are four influenza antiviral drugs
approved for use in the United States (oseltamivir,
zanamivir, amantadine and rimantadine). The
swine influenza A (H1N1) viruses that have
been detected in humans in the United States
and Mexico are resistant to amantadine and
rimantadine so these drugs will not work
against these swine influenza viruses.
Laboratory testing on these swine influenza
A (H1N1) viruses so far indicate that they
are susceptible (sensitive) to oseltamivir
and zanamivir.
Benefits of Antiviral Drugs
Treatment:
If you get sick, antiviral drugs can make
your illness milder and make you feel better
faster. They may also prevent serious
influenza complications. Influenza antiviral
drugs work best when started soon after
illness onset (within two [2] days), but
treatment with antiviral drugs should still
be considered after 48 hours of symptom
onset, particularly for hospitalized
patients or people at high risk for
influenza-related complications.
Prevention:
Influenza antiviral drugs also can be used
to prevent influenza when they are given to
a person who is not ill, but who has been or
may be near a person with swine influenza.
When used to prevent the flu, antiviral
drugs are about 70% to 90% effective. When
used for prevention, the number of days that
they should be used will vary depending on a
person’s particular situation.
Centers for Disease
Control and Prevention (CDC) Recommendation
CDC recommends the use of oseltamivir or
zanamivir for the treatment and/or
prevention of infection with swine influenza
viruses.
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Oseltamivir (brand name Tamiflu ®) is
approved to both treat and prevent
influenza A and B virus infection in
people one year of age and older.
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Zanamivir (brand name Relenza ®) is
approved to treat influenza A and B
virus infection in people 7 years and
older and to prevent influenza A and B
virus infection in people 5 years and
older.
Recommendations for using antiviral drugs
for treatment or prevention of swine
influenza will change as we learn more about
this new virus.
Clinicians should consider treating any
person with confirmed or suspected swine
influenza with an antiviral drug.
Source: CDC
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