Swine Flu (cont.)
In this Article
What is the history of swine flu (H1N1) in humans?
In 1976, there was an outbreak of swine flu at Fort Dix. This virus is not the same as the 2009 outbreak, but it was similar insofar as it was an influenza A virus that had similarities to the swine flu virus. There was one death at Fort Dix. The government decided to produce a vaccine against this virus, but the vaccine was associated with neurological complications (Guillain-Barré syndrome) and was discontinued. Some individuals speculate that formalin, used to inactivate the virus, may have played a role in the development of this complication in 1976. There is no evidence that anyone who obtained this vaccine would be protected against the 2009 swine flu. One of the reasons it takes a few months to develop a new vaccine is to test the vaccine for safety to avoid the complications seen in the 1976 vaccine. New vaccines against any flu virus type are usually made by growing virus particles in eggs. A serious side effect (allergic reaction such as swelling of the airway) to vaccines can occur in people who are allergic to eggs; these people should not get flu vaccines. Individuals with active infections or diseases of the nervous system are also not recommended to get flu vaccines.
Can novel H1N1 swine flu be prevented with a vaccine?
The best way to prevent novel H1N1 swine flu would be the same best way to prevent other influenza infections, and that is vaccination. The CDC has multiple recommendations for vaccination based on who should obtain the first doses when the vaccine becomes available (to protect the most susceptible populations) and according to age groups. The CDC based the recommendations on data obtained from vaccine trials and infection reports gathered over the last few months. The current (October 2009) vaccine recommendations from the CDC say the following groups should get the vaccine as soon as it is available:
- pregnant women,
- people who live with or provide care for children younger
than 6 months of age,
- health-care and emergency medical services personnel,
-
people between 6 months and 24 years of age, and
- people from the ages of
25 through 64 who are at higher risk because of chronic health disorders such as
asthma, diabetes, or a weakened immune system.
Currently, the CDC is stating that people ages 10 and above are likely to need only one vaccine shot to provide protection against novel H1N1 swine flu and further suggest that these shots will be effective in about 76% of people who obtain the vaccine. New vaccine trial data showed that healthy adults produce protective antibodies in about 98% of people in 21 days. Unfortunately, the vaccine shot in children ages 6 months to 9 years of age is not as effective as it is in older children and adults. Consequently, the CDC currently recommends that for ages 6 months up to and including 9 years of age, the children obtain two shots of the novel H1N1 vaccine, the second shot 21 days after the first shot.
Pregnant women are strongly suggested to get vaccinated as stated above.
Although some vaccine preparations (multidose vials) contain low levels of
thimerosal preservative (a mercury-containing preservative), the CDC still
considers the vaccine safe for the fetus and mother. However, some vaccine
preparations that are in single-dose vials will not have thimerosal
preservative, so those pregnant individuals who are concerned about thimerosal
can get this vaccine preparation when it is available.
Another type of vaccine (currently named Influenza A [H1N1] 2009 Monovalent Vaccine Live, Intranasal) has been made available during the first week in October 2009. It is a live attenuated novel H1N1 flu vaccine that contains no thimerosal, is produced by MedImmune, LLC, and is sprayed into the nostrils. This vaccine is only for healthy people 2-49 years of age, and some data suggest that it is less effective in generating an immune response in adults than the vaccine injection. The dosing schedule is as follows:
- Children 2-9 years of age should receive two doses (0.1 ml in each nostril; total
equals 0.2 ml per dose) -- the second dose should be given the same way about one
month after the first dose
- Children, adolescents and adults, 10-49 years of age should receive one dose -- (0.1 ml in each nostril; total equals 0.2 ml per dose)
The CDC occasionally makes changes and updates its information on vaccines
and other recommendations about the current flu pandemic. The CDC states, "for the
most accurate health information, visit http://www.cdc.gov or call 1-800-CDC-INFO,
24/7." Caregivers should check the vaccine package inserts for more detailed
information on the vaccines when they become available. This article has an
updated timeline for novel H1N1 swine flu attached (see below) and provides the
reader with current details about the pandemic.
The following is a list of the CDC-approved H1N1 vaccines and the companies that name and manufacture them as of 10/29/09:
- Influenza A (H1N1) 2009 Monovalent Vaccine by Sanofi Pasteur
- Influenza A (H1N1) 2009 Monovalent Vaccine by Novartis
- Influenza A (H1N1) 2009 Monovalent Vaccine Live, Intranasal by MedImmune, LLC
- Influenza A (H1N1) 2009 Monovalent Vaccine by CSL Limited
The CDC says that a good way to prevent any flu disease is to avoid exposure
to the virus; this is done by frequent hand washing, not touching your hands to
your face (especially the nose and mouth), and avoiding any close proximity to
or touching any person who may have flu symptoms. Since the virus can remain
viable and infectious for about 48 hours on many surfaces, good hygiene and
cleaning with soap and water or alcohol-based hand disinfectants are also
recommended. Some physicians say face masks may help prevent getting airborne
flu viruses (for example, from a cough or sneeze), but others think the better
use for masks would be on those people who have symptoms and sneeze or cough.
The use of Tamiflu or Relenza may help prevent the flu if taken before symptoms
develop or reduce symptoms if taken within about 48 hours after symptoms
develop. Some investigators say that administration of these drugs is still
useful after 48 hours, especially in high-risk patient populations .However,
taking these drugs is not routinely recommended for prevention for the healthy
population because investigators suggest that as occurs with most drugs, flu
strains will develop resistance to these medications. Recently, the CDC made
further suggestions about the use of these antiviral medications. Dr. Schuchat,
a CDC official, indicated that three modifications were being suggested
(Sept. 8, 2009) to the interim guidelines for use of Tamiflu and Relenza:
1. Patients with high-risk factors should discuss flu symptoms and when to
use antiviral medications; doctors should provide a prescription for the
antiviral drug for the patient to use if the patient is exposed to flu or
develops flu-like symptoms without having to go in to see the doctor.
2.
"Watchful waiting" was added as a response to taking antiviral medications, with
the emphasis on the fact that those people who develop fever and have a
preexisting health condition should then begin the antiviral medication.
3. The
antiviral medications are the first-line medicines for treatment of novel H1N1
swine flu, and most current cases of flu are novel H1N1 and are, to date,
susceptible to Tamiflu and Relenza.
Your doctor should be consulted before these drugs are prescribed.
In general, preventive measures to prevent the spread of flu are often
undertaken by those people who have symptoms. Symptomatic people should stay at
home, avoid crowds, and take off from work or school until the disease is no
longer transmittable (about two to three weeks) or until medical help and advice is
sought. Sneezing, coughing, and nasal secretions need to be kept away from other
people; simply using tissues and disposing of them will help others.
Quarantining patients is usually not warranted, but such measures depend on the
severity of the disease. The CDC recommends that people who appear to have an
influenza-like illness upon arrival at work or school or become ill during the
day be promptly separated from other people and be advised to go home until at
least 24 hours after they are free of fever (100 F [37.8 C] or greater), or
signs of a fever, without the use of fever-reducing medications. The novel H1N1
swine flu disease takes about seven to 10 days before fevers stop, but new research
data (Sept. 14, 2009) suggests waiting until the cough is gone since many people are
still infectious about one week after fever is gone. The CDC has not yet
extended their recommendations to stay home for that extra week.
Next: Can H1N1 be prevented if the H1N1 flu vaccine is not readily available? »
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