通用流感疫苗开始在人体实验

The World Health Organization says about 500,000 people die every year from seasonal flu. To combat that, doctors recommend getting a flu vaccine at the beginning of each flu season and researchers are now working on a universal vaccine that could protect people from all strains of the flu.  What's more, they say the vaccine could work for several years.

This pediatrician's office in Atlanta, Georgia is busy taking calls.

The state of Georgia in southern United Sates has reported the nation's most number of flu cases this year. Influenza viruses are uNPRedictable and this year, health officials say they are seeing several strains.

Dr. Jennifer Shu is with Children's Medical Group in Atlanta. "In our office, we are seeing influenza B, plus an influenza A strain, which I believe the CDC (Center for Disease Control and Prevention) says most of that circulating right now is H3N2, although there is some that's H1N1," she said.

To guard against the flu, health officials recommend vaccines before the each  flu season for everyone six months and older .  This year's vaccine protects against all the strains of flu circulating right now, but scientists have to make an educated guess about which flu virus will circulate next year. Then new vaccines will have to be produced .

Researchers working on the universal flu vaccine say that yearly flu shots will become a thing of the past if a new vaccine proves successful. Dr. Anthony Fauci is the director of the National Institute of Allergy and Infectious Diseases in Washington.

"The concept has been proven in mice and ferrets and in monkeys that you can actually do that. It is very likely since studies have already been started in humans that we can illicit that type of immune response in humans," he said.

When the scientists gave the vaccine to ferrets, the animals produced antibodies that protected them against a wide range of flu strains. Dr. Fauci explains the science of this vaccine.

"There is a part of the virus called the stem. So if this is the bulb - this is the stem [shows using his hand]. We were able to identify part of this hemagglutinin that doesn't change from one virus to another. So we determined, can you make an antibody response against that stem, and the answer is yes you can," he said.

Flu viruses can mutate faster than vaccines can be made using current technology.  That's how epidemics get started.

But researchers say if this universal vaccine is successful in human trials, it will provide protection from all strains of the influenza virus.  What's more, it could be given to children and provide protection over the better part of their lives.
Again, Dr. Fauci.

"The work is important because the concept that you could vaccinate with a component of a vaccine of the virus that was a 1999 strain and illicit antibodies that in mice and in ferrets and other animal models protect in everything from 1934 and 2007 is a very important concept," he said.

In 2009, vaccines were in short supply when the H1N1 circulated around the world. Production was slow because scientists must first grow the virus in millions of eggs, and the process takes a long time.

But scientists say a universal vaccine will not rely on growing viruses in eggs. They will produce it by using the genetic sequencing of the flu, so it will be available faster, fewer people will get sick and die and it will be much cheaper than producing a new flu vaccine every year.