— It’s been just a week since Monica Hankins first heard scientists were looking for volunteers to test an experimental vaccine to prevent the H1N1 swine flu, but the Festus, Mo., mom and her family already are signed up.
She wants her two young daughters, Isabella, 3, and Maya, 19 months, to be among the first to be protected against the previously unknown virus that has launched a global pandemic and claimed more than 800 lives worldwide, including more than 300 in the United States.
“I kind of jumped at the chance,” said Hankins, 28, a home health care worker. “The way that it’s sounding, it’s something that I’ve never experienced before. It’s really scary to me.”
From Seattle to St. Louis, at least 3,000 people so far have told scientists they’re eager to be part of fast-track clinical trials to assess the early safety of a shot aimed at preventing widespread infection, serious illness or death in a huge swath of the U.S. population.
That’s already more than the estimated 2,800 volunteers needed at the eight trial sites across the nation.
“We don’t generally ever get a response like this,” said Dr. Lisa Jackson, the principal researcher who’s heading the trials at Group Health Cooperative in Seattle, where nearly 1,100 people flooded phone lines within the first two days.
“It’s huge,” said Dr. Sharon E. Frey, the chief investigator at St. Louis University, where staff members have fielded 700 calls so far. Hankins and her family plan to participate there.
The volunteers may be motivated by a range of reasons, from altruism and patriotism to simple self-protection, said Dr. Wendy Keitel, the chief investigator for the trials at the Baylor College of Medicine in Houston.
“Many of our volunteers are specifically interested in making a contribution to the science and to medicine,” Keitel said. “Some are concerned about their own vulnerability.”
‘I'd just rather not get it.'
Ann Goldberg, 35, a Seattle research reviewer, said she just wants to head off a nasty bug if she can.
“When I do get the flu, I get knocked out and I’d just rather not get it,” she said.
A smaller motivation may be the compensation most volunteers receive. Hankins said she was told she and her family members would be paid $50 apiece for each of the three or four visits they expect to make to the clinic.
Researchers are seeking healthy adults ages 18 to 64, as well as elderly volunteers older than 65 and children ages 6 months to 17 years. They’ll be recruited initially for five trials conducted by the Vaccine and Treatment Evaluation Units, research stations specially selected for their ability to quickly evaluate vaccine effects.
Early trials will look at how much H1N1 vaccine, and how many doses, are necessary to stimulate a solid immune system response to the virus. Early trials will evaluate whether one or two 15-microgram doses of vaccine, or one or two 30-microgram doses, are needed to induce protection.
“Is one shot enough, or do you need two shots for those people who have never seen this strain before?” Frey said.
Starting in about two weeks, the adult doses will be given 21 days apart, testing vaccines made by Sanofi Pasteur and CSL Biotherapies. If early evidence suggests they’re safe, similar trials would be started in children.
At the same time, scientists will launch studies to determine whether it’s safe to give the normal seasonal flu vaccine along with the new H1N1 vaccine in adults and children.
Lab tests are expected to be processed in real time, as quickly as possible, with results expected as soon as early September, scientists said.
Researchers are conducting the trials over weeks instead of months or longer, hoping to assess safety in time to approve release of the H1N1 vaccine in the fall, before the virus is likely to spread widely in the general population.
Virus could sicken 36 percent of U.S. population
About 54 percent of the U.S. population could be infected, with about 36 percent actually becoming ill with symptoms, said Ira Longini, a leading influenza researcher at the University of Washington School of Public Health. Longini shared latest estimates based on research pending publication.
That squares with older modeling estimates from the CDC that showed that up to 40 percent of the U.S. population could become ill over two years during a pandemic without interventions such as vaccines.
So far, most of the more than 43,000 confirmed cases of swine flu in the United States have been mild. But scientists say that could change if the virus mutates and becomes more virulent. So far, there's been no sign of that. The vaccine could help slow that process by limiting the number of new infections.
The new vaccine is expected to be as safe as any flu shot given during a regular season, said Keitel, the Baylor researcher. She and other scientists say the new vaccine is merely a “strain change,” a shift similar to altering the mix of seasonal vaccines depending on which flu bug is expected to circulate each year.
This vaccine, like all flu vaccines, contains inactivated virus proteins, so there's no danger of getting the actual virus.
But because this particular virus has not been seen before, most of the population has no immunity to it, Keitel noted. “Because it is so different, they may have different immunization needs.”
Researchers don’t expect side effects to vary from normal flu vaccine: redness and soreness at the injection site, perhaps fever, especially in young children.
But they’ll be looking for alarming effects, such as widespread allergic reactions or fever in adults, noted Jackson, the Seattle researcher. These trials are too short and too limited in size to detect more serious problems, such as Guillain-Barre Syndrome, a neurological disorder that developed in 1 out of every 100,000 people who received vaccine during a swine flu epidemic in 1976.
“Any time you conduct a large campaign, you have to be concerned,” Keitel said.
At-risk populations to get vaccine first
If all goes well, the trials would pave the way for use of up to as many as 200 million doses of swine flu the U.S. has procured for the fall.
A CDC vaccine advisory panel on Wednesday recommended that first shots should go to pregnant women, household contacts of infants younger than 6 months, health care workers, young people ages 6 months to 24 years and non-elderly adults at high risk for the flu.
If supplies are very limited, the panel suggested prioritizing pregnant women, household contacts of children younger than 6 months, health care workers who have direct contact with ill people, children ages 6 months to 4 years and youngsters ages 5 to 18 to have greater risk factors for flu.
The CDC typically follows the panel's advice.
Hankins said she hopes that the vaccine is as effective and free of side effects as scientists expect. She’s more worried, though, about the risks of swine flu and wants to protect her family as soon as possible.
“I’ve been watching this and it does concern me quite a bit,” she said. “This one really bothers me.”