Scientists aim to dispel fears on H1N1 flu vaccine
Untested? No.
Rushed into production? Not really.
Full of substances that do harm? Hardly, and especially not compared with the dangers of the H1N1 flu virus.
These are the retorts of researchers, scientists, federal health authorities and others familiar with how the swine flu vaccine is being made as they listen to the debate unfolding around kitchen tables and over the Internet.
“We’ve been baking this bread for 60 years, and we’re pretty good at it,” said Kenneth Alexander, an infectious disease expert at the University of Chicago, expressing the frustration that decades of experience in making flu vaccines hasn’t resulted in more public confidence.
Jesse Goodman, the Food and Drug Administration’s acting deputy commissioner for public health, said the swine flu vaccine was “the absolute best protection” available, and perfectly safe.
“We think it is important,” Goodman said, “to have the actual facts laid out and let people make their own decisions.”
When the H1N1 virus first appeared in April in Mexico and California, federal health officials sent samples to pharmaceutical companies so they could formulate their vaccine versions for field testing.
Mass production geared up in August, and the first 2 million doses were delivered to doctors and clinics two weeks ago. Officials at the Centers for Disease Control and Prevention recently acknowledged slower production than they had hoped, but predicted “widespread availability” by the beginning of November.
That turnaround from discovery to delivery was fast enough that many Americans who told pollsters they don’t plan to vaccinate their children said they were worried the vaccine had been rushed into production before being tested adequately for potential side effects.
Nonsense, Alexander said.
“This H1N1 vaccine is made just like all the flu vaccines we have been making for 60 years, which have an extraordinary record for safety,” he said.
“The only difference between this one and the seasonal flu shots is the virus it is made from, so we have no reason to believe this one will be any less safe.”
Although pharmaceutical researchers worldwide are trying to find newer and speedier ways to make flu vaccines, in the U.S., the only FDA-approved method is from the 1940s: injecting the virus into chicken eggs to be grown into larger quantities.
For the arm-shot vaccine, the virus eventually is harvested from the eggs, killed and chopped into segments. When injected into the recipient, it activates the body’s immune system to produce antibodies that kill the actual flu virus if the recipient is exposed.
The alternative, nasal-spray vaccine is made using a live virus. It too is grown in eggs, but at lower temperatures, weakening or “attenuating” it so that it can survive only in the nose, not at greater body heats in the lungs.
“The nasal vaccine infects the mucosal cells [in the nose], which are closely monitored by our immune system,” said Patrick Wilson, a University of Chicago immunologist. Once that system detects the vaccine, Wilson said, it produces permanent immunity to the targeted flu virus.
The first testing of both vaccines was performed on 3,000 volunteers in eight laboratories at Baylor University in Texas, Cincinnati Children’s Hospital Medical Center, Emory University in Georgia, Seattle Group Health Cooperative, St. Louis University, University of Iowa, University of Maryland and Vanderbilt University in Nashville.
It also is being tested on volunteers by the five companies licensed to make as many as 250 million doses of the vaccine by next spring for the U.S. market -- CSL Ltd., Novartis Vaccines, Sanofi Pasteur, GlaxoSmithKline and MedImmune.
“It is tested to see if it produces the level of antibody production in the blood that reaches the FDA standard,” said William Schaffner, an infectious disease specialist at Vanderbilt.
“It is also tested for safety in the volunteers, something I know a little bit about since I was one of the volunteers for this vaccine.”
On its website, the FDA has posted the contents of the vaccines produced by the five companies.
Schaffner said that, like many foods and medicines, they contain a number of vital chemical substances that could be toxic in large volume but are in such tiny amounts that they are harmless.
The most questioned ingredient is thimerosal, a preservative added in trace amounts to keep vaccine in two-shot doses from deteriorating if stored while awaiting application.
Thimerasol contains ethyl mercury, and critics allege it can cause autism and other neurological disorders. But researchers say there is so little thimerasol in the vaccine that it poses no harm. Nevertheless, they have produced thimerosal-free single-shot doses that can be ordered, and they say there is no thimerosal in the nasal spray.
“I continue to be amazed that people bring this issue up,” said Paul Offit, a pediatrician and University of Pennsylvania vaccine researcher. “There have been six exhaustive studies [of a possible link between thimerosal and autism]. . . . They each came back with a definitive answer: No. Three other studies were done to see if thimerasol caused any signs of mercury poisoning. All three answered: No.”
Thimerosal is no longer used in most childhood vaccines, however, because of potential health concerns.
Others have raised concerns about “adjuvants” -- compounds sometimes added to vaccines to stimulate the immune response in recipients. It is added in several European nations, but not in the U.S.
Dr. Anne Schuchat, the CDC’s director of immunization and respiratory diseases, said the U.S. sees no need to add them unless the virus mutates into a far deadlier form.
“Since April, this flu has caused tens of thousands of hospitalizations and more than a thousand deaths,” Offit said. “This is only October, and influenza is a winter disease, so no telling what we are about to see.
“We should thank the Lord that we have this vaccine at this stage.”
--
