Greetings jat,
What a timely question! Flu vaccines have been available for 60 years,
and yet each year, 10% to 20% of the total world population will be
afflicted with the flu! This translates to about 4 million cases of
severe illness and around 400,000 deaths worldwide. To have adequate
stores of flu vaccine at the ready each year is a tremendous task, and
one that often is impossible. Because the vaccine is made from
different strains of the influenza virus each year, and requires a
great deal of research and prep time, stockpiling vaccine is not an
option. This leaves occasional shortages in epidemic areas.
http://www.who.int/csr/disease/influenza/sars/en/
Keeping the number of global influenza cases each year to a minimum is
a huge job, one that is well done by the collaboration of numerous
agencies around the world.
Keeping up with flu viruses requires the constant vigilance of many
organizations, including 110 National Influenza Centers, WHO (World
Health Organization), along with WHO laboratories in 83 countries, as
well as the US Department of Health and Human Services, state and
local health authorities, and the medical community in general.
In the hospital I work for, during flu season ER patients with flu
symptoms have their noses and/or throats cultured. These specimens are
sent to the State Lab for identification. The information is tabulated
and sent up the investigative chain. This is one way that numbers and
locations of cases are documented, and influenza strains are
identified.
Research Centers for Influenza are located in London, Atlanta,
Melbourne and Tokyo, where viruses are studied. The virus samples are
collected in approximately 180 countries. ??the CDC actively monitors
U.S. disease activity and deaths related to influenza between October
and May of each year.?
Some of these isolated viruses are sent to the CDC in Atlanta for
testing. Here, the CDC looks at all the data collected to determine
the most virulent strains, and those most likely to result in flu
outbreaks. Once the CDC determines which flu virus has the potential
for an epidemic, the information is presented to WHO and the FDA (Food
and Drug Administration) where the next season?s vaccine can be
formulated. It?s not impossible to stockpile a great deal flu vaccine,
as the strain changes year to year.
http://www.cdc.gov/od/nvpo/pandemics/flu4.htm
http://www.who.int/csr/alertresponse/field/en/
http://www.who.int/gb/EB_WHA/PDF/EB111/eeb11110.pdf
How are vaccines made?
Vaccines can be as simple as an ancient Chinese method of inhaling
dried and pulverized smallpox lesion scabs to today?s modern vaccines,
made in controlled environments, and injected with sterile syringes
and needles.
http://www.accessexcellence.org/AE/AEC/CC/vaccines_how_why.html
In the case of the flu vaccine, the virus used is a dead virus of the
type that is causing flu, or expected to cause outbreaks. In some
vaccines, notably the MMR and the polio vaccines, an attenuated virus
is used. This means the virus is cultured repeatedly until it loses
most of its virulence (ability to cause disease). The body still
recognizes it as a pathogen, and develops protective antibodies.
http://www.immunisation.nhs.uk/howmade.html
http://www.nlm.nih.gov/medlineplus/ency/imagepages/9469.htm
Vaccine production is an amazing process. The FDA supplies four
pharmaceutical companies, in the US, with the three chosen strains of
the current year?s flu viruses, based on the data gathered by the
health organizations.
The virus is injected into specially cleaned and disinfected 11
day old chicken eggs. The eggs are incubated for a specified time. The
egg whites are next removed, as this is where the virus has been
replicating. The egg white is then purified to remove large proteins,
and treated with formalin to kill the virus. The virus is then
?split?, breaking the virus into fragments. (Fragments, rather than
intact proteins confer a stronger immunity).
This process is performed, simultaneously to three strains of
virus. Once the egg white liquid is purified and split, the ?brew? of
all three strains is mixed (This is where the name ?Trivalent? that
you see associated with flu vaccines comes in). At this point, the
?brew?, now vaccine, is quality controlled; the strength of the
vaccine is checked to be sure it is strong enough to produce an immune
response in the patient, and purity is re-checked.
Next the FDA checks each lot of vaccine, and must approve each
lot, by ?releasing? the batch for shipment. The vaccine is then ready
to label, package and ship; all this must be done in time to ship in
September, the beginning of ?Flu shot season?
This Aventis Pasteur Pharmaceutical site has some excellent videos
showing the process. There are 7 videos, available in Windows Media
Player and Quick Time formats.
http://www.influenzaconnection.com/video.html
This PBS site has a Flash video on the making of vaccines. This video
does not include flu vaccine, but the process for making the killed
polio vaccine is similar enough that you can get the idea. Look for
the ?Guide to making vaccines? link, to the right of the center of
the page, under the illustration of viruses.
http://www.pbs.org/wgbh/nova/bioterror/vacc_flash.html
A good resource site, you can see flu alerts, and learn about ?Flu
Hunters?, folks who track and report flu outbreaks. A state by state
Flu Map is here too,
http://www.fluwatch.com/index2.html
Influenza Connection has a pictorial timeline of vaccine production:
http://www.influenzaconnection.com/pdf/productiongraphic.pdf
Flu vaccine selection and manufacture the CDC actively monitors U.S.
disease activity and deaths related to influenza between October and
May of each year. This information is provided each week in influenza
surveillance summaries.
http://www.cdc.gov/od/nvpo/pandemics/flu4.htm
======================================
20th century pandemics and scares:
http://www.cdc.gov/od/nvpo/pandemics/flu3.htm
From the CDC, a list of flu vaccine manufacturers
http://www.who.int/csr/disease/influenza/manulist/en/
CDC has a nifty little flu-risk calculator by state:
http://www2a.cdc.gov/od/fluaid/fluaid_page1.asp
Vaccines of the future: Got bananas?
http://whyfiles.org/166plant_vaccines/index.html
http://www.twnside.org.sg/title/twr127d.htm
Some pertinent articles on flu vaccine shortages:
http://www.ama-assn.org/amednews/2003/11/17/hlsc1117.htm
http://www.hida.org/govtrelations/article.asp?Article_ID=530&Subj_ID=173
European Influenza Surveillance Scheme has a weekly bulletin, to stay
updated on influenza:
http://www.eiss.org/cgi-files/bulletin_v2.cgi
SARS and vaccines
http://www.who.int/csr/disease/influenza/sars/en/
The word ?vaccine? comes from the Latin word for cow, ?vacca?. You can
read about the history of vaccines here:
http://www.accessexcellence.org/AE/AEC/CC/vaccines_how_why.html
Hope this helps you understand the vaccine production process! I hope
you are able to evade the flu bug yourself this year- have you had
YOUR flu shot?
If any part of my answer is unclear, please request an Answer
Clarification before rating this answer. This will enable me to assist
you further.
Regards,
crabcakes-ga
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