A new study, published Sunday in the journal Nature, found that people who lived through the 1918 flu pandemic, the worst in human memory, can still produce antibodies to kill the deadly strain of the H1N1 flu.
American scientists reached their findings after studying 32 people aged 92 to 102 who lived through the 1918 flu. They tested the blood of all participants, and found that even 90 years later all had antibodies in their blood to destroy the virus with efficiency.
The team of US researchers, headed by Dr. James E. Crowe Jr., a professor of pediatrics, microbiology and immunology
define at Vanderbilt University, also found that some volunteers even had the cells which produce the antibodies.
In experiments with mice, Dr. Crowe’s team found that these antibodies continue to protect the mice from infection with the 1918 flu strain. The team manipulated the volunteers’ antibodies into a vaccine and found that it kept alive all the mice they injected with the killer virus.
"It was very surprising that these subjects would still have cells floating in their blood so long afterward," said Dr. Crowe. "Most people have a notion that elderly people have very weak immunity or they have lost immunity. This study shows that extremely elderly people have retained memory of being infected with the 1918 flu, even 90 years later."
Dr. Crowe suggests the similar antibodies could be developed to kill new strains of bird flu that currently is circulating in Asia, Europe, the Middle East and Africa. He hopes to use similar techniques to enhance the efficacy of vaccines that would be more useful against newer bird flu strains.
"This study shows that humans can develop very potent immune responses against dangerous influenza that cause pandemics," Dr. Crowe said. "It gives us hope that we can develop vaccines and antibody treatments for any other pandemic viruses that come along."
The Spanish flu outbreak of 1918, which was an H1N1 strain that apparently came straight from birds, swept around the world at the end of World War One, killing about 50 million people.
H5N1, also known as A(H5N1), is a subtype of the Influenza A virus that is capable of causing illness in many animal species, including humans, while a bird-adapted strain of H5N1, called "highly pathogenic avian influenza virus of type A of subtype H5N1 {HPAI A(H5N1)}, is the causative agent of H5N1 flu, commonly known as "avian influenza" or simply "bird flu", and is endemic in many bird populations, especially in Southeast Asia.
The H5N1 virus though remains primarily a virus of birds, but experts fear that once it starts transmitting from person to person, like the H1N1 virus did in 1918, it would sweep the world, leaving millions more to die and triggering a devastating human pandemic.
Since the deadly H5N1 strain re-emerged in Asia in 2003, it has infected more than 385 people and killed 243 of them.
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