Tuesday, 11 August 2009

vaccine yield is only 50%

But it is only for the current seed of Swine Flu virus. A new seed is
expected to give a better yield. Let us pray that it will be
sufficient for the most needy people.


Vaccine trials off to fast start for pandemic flu
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Nurse Carolyn Stefanski gives a shot to Nicholas Sarakas, 25, of St.
Peters, during an H1N1 vaccination trial at the Saint Louis University
Hospital in St. Louis, Mo. "Somebody has to do it, and I was probably
going to get it anyway," Sarakas said.
Enlarge image Enlarge By Emily Rasinski, St. Louis Post-Dispatch via
Nurse Carolyn Stefanski gives a shot to Nicholas Sarakas, 25, of St.
Peters, during an H1N1 vaccination trial at the Saint Louis University
Hospital in St. Louis, Mo. "Somebody has to do it, and I was probably
going to get it anyway," Sarakas said.

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By Steve Sternberg, USA TODAY
Nicholas Sarakas says his mother urged him not to take part in
pandemic vaccine trials. "She was worried about me. She didn't want
them guinea-pigging me," he says. "She made me promise never to be in
another clinical trial."

Sarakas, 25, decided to volunteer anyway. A college student without
health insurance at the University of Missouri in St. Louis, he
reasoned that he'd rather take his chances with the vaccine, and its
risks, than pandemic flu.

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"There are people my age that are dying from this," he says.

Early Monday, Sarakas rolled up his sleeves for an injection in each
arm, becoming one of dozens of adults enrolling in an unprecedented
flurry of fast-track flu vaccine trials that will grow to include
11,131 adults and 5,740 children, with more trials planned.

The vaccine is designed to blunt the effect of a virus that, starting
this fall, could infect 100 million people in the USA and cause 30,000
to 90,000 deaths based on scenarios drawn from past pandemics, says
Arnold Monto of the University of Michigan, an adviser to the Centers
for Disease Control and Prevention and the World Health Organization.
About 36,000 people in the USA die each year of flu.

The virus, a new type of H1N1 strain also known as swine flu, has been
linked to 6,506 hospitalizations and 436 deaths in the USA — up from
353 a week ago — since it emerged in Mexico in April.

Too many volunteers to count

The U.S. government has ordered roughly 195 million doses of pandemic
flu vaccine, in addition to the 120 million doses of seasonal flu
vaccine expected to be available by the end of September.

"Vaccine is a huge component of the public health response to
influenza," says Anthony Fauci, director of the National Institute of
Allergy and Infectious Diseases, which is sponsoring the trial that
enrolled Sarakas at Saint Louis University and four other trials at
eight federally funded vaccine research centers across the country.

The flurry of swine flu vaccine trials, some sponsored by the U.S.
government and others by five vaccine manufacturers, began late last
week. Now people are clamoring to take part.

"We've had over 1,000 people call wanting to participate," says Sharon
Frey, lead investigator of the St. Louis study. "We've stopped

Frey says she expects to meet her quota of 200 volunteers by next
week, thanks to widespread publicity.

Side effects, dosages unknown

"I feel really lucky that I get to participate," says Karla Payne, 54,
of Westchester, Ohio, who got her shots Monday in a study at
Cincinnati Children's Hospital Medical Center. "I used to work in the
public schools. So many students didn't have money for health care.
When I saw in the paper that they would start using schools to
vaccinate kids, I thought, gosh, this would be a good thing to do,
because they need to get vaccine out there."

The studies are necessary because so little is known about the
pandemic vaccine, though many researchers believe it is likely to act
much like seasonal vaccines, says Bruce Gellin, director of the
Department of Health and Human Services National Vaccine Program

Flu vaccines historically have few side effects beyond redness and
soreness at the infection site. Studies of several thousand volunteers
aren't big enough to detect more subtle side effects such as Guillain-
Barré syndrome, a rare nerve ailment that crops up in one of every
million flu vaccine recipients. Federal health agencies have ramped up
surveillance efforts to detect any severe side effects that might

There are other uncertainties as well. For instance, vaccine makers
don't know how big a dose to give, how many doses will be needed per
person for protection and whether it will be necessary to add an
immune-booster called an adjuvant.

Each one of those factors may affect how many people can be
vaccinated. For instance, if the usual 15-microgram dose has to be
doubled, the number of people who could be vaccinated would fall to 98
million. If two shots are required at double the dose, the number of
people who could be vaccinated would drop further, to 50 million.

Andrin Oswald, CEO of Novartis vaccines and diagnostics, says vaccine
makers also have found that the seed virus needed to make H1N1 vaccine
produces just half the yield of seasonal vaccine viruses. The low
yield may slow vaccine production so much that pandemic vaccine may be
in short supply during the fall flu surge, he says.

"What we normally say in our orders to the government is that if the
yield is 100%, we could deliver 10 million doses by December. If it's
only 50%, it would take until March," Oswald says, adding that
manufacturers now have a new seed strain that may boost yields.

"Timing is everything," Monto says. "We believe the second wave of flu
will come in the fall. If vaccine doesn't arrive until November-
December, it won't do as much good."

By the numbers:

The U.S. government and five companies on Monday began injecting
volunteers to test a new vaccine to guard against the H1N1 flu strain.
If effective, the vaccine will begin to be available to the general
public in mid October.

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