The reason for that is that the influenza virus has a rapid rate of mutation, forcing companies that manufacture the vaccine to make their best guess as to which flu types will be more prevalent in a given season.
Experiments in Germany tested 22 flavonoids on human lung cells infected with the H5N1 influenza A virus.
Swine flu is a respiratory disease which is caused by a strain of the influenza type A virus known as H1N1.
This year's North American vaccine is made from three viruses: two types of influenza A virus (H3N2 and H1N1) and an influenza B virus.
The virus that is contagious between humans does not yet exist (or it may just have come into being inside a young person in China who contacted both vH7N9 and a human influenza A virus to which they were not immune).
FORBES: Urgent Warning On New Bird Flu H7N9: Could Pose Global Threat
Two common gut bacteria, Escherichia coli and Helicobacter pylori, and also the influenza-A virus, are particularly adept at playing the evasive game of molecular mimicry, and the team is now looking at possible connections between different gut bacteria and autoantibodies against melanocortins to see if they can pin down which, if any, of these bugs might be responsible.
The children were infected with a virus known as swine influenza A H1N1, which has a unique combination of genes not previously seen in flu viruses in either humans or swine - although it shares similarities with a virus that has been circulating in pigs since 1999.
As of January 5, the CDC said Friday, the predominant virus in the United States was an influenza A (H3N2) virus that matched well with the H3N2 virus represented in the vaccine.
It is caused by a type-A influenza virus.
CNN: Inaccurate 'swine' flu label hurts industry, pork producers say
According to Dr. Ron Fouchier, a Dutch virologist, this mutation allows the virus to reproduce at much lower temperatures than a standard avian influenza virus.
Unlike cold viruses, which have been tested in humans, influenza is a potentially deadly virus.
The H7N9 strain has lead to the usual concerns about the virus causing a deadly influenza epidemic in China.
Since neither of the two children, a 10-year-old boy and a 9-year-old girl, had contact with pigs, it "increases the possibility that human-to-human transmission of this new influenza virus has occurred, " according to a CDC report.
We shouldn't be seeing this much influenza and it's with a new virus and that's the cause fo the concern.
CNN: 2 U.S. swine flu dead had other health problems, officials say
The World Health Organization declared the virus, also known as the novel influenza A(H1N1), a global pandemic June 11.
All influenza vaccines are made by growing influenza virus particles in chicken eggs before treating them in a way to kill (inactivate) or weaken the viruses.
Person-to-person transmission is believed to occur in a manner similar to the spread of the influenza virus: through infected people coughing and sneezing, the CDC said.
Flavonoids and flu: Two plant-based flavonoids disease-fighting compounds found in many foods significantly impaired the infectious activity of H5N1 avian-flu virus in laboratory experiments and may form the basis of future influenza treatments, a report in Antiviral Research says.
The archaic technology for making them, which involves injecting influenza virus into chicken eggs and separating out the resulting antibodies, only allows for a few flu strains to be included and they must be picked far in advance.
FORBES: The Flu Shot's Not A Great Vaccine, But You Should Get One Anyway
The new virus has genes from North American swine influenza, avian influenza, human influenza and a form of swine influenza normally found in Asia and Europe, said Nancy Cox, chief of the CDC's Influenza Division.
CNN: Among the swine flu mysteries: Why only deaths in Mexico?
应用推荐