UC Davis pair confirm findings on seniors' immunity to swine flu

Wednesday, Oct. 14, 2009
UC Davis pair confirm findings on seniors' immunity to swine flu
By Anita Creamer - acreamer@sacbee.com
New research by a pair of UC Davis School of Veterinary Medicine scientists confirms previous theories that people 65 and older may be protected from the most serious effects of the novel H1N1 virus by many decades' worth of previous exposure to other flu viruses.

"The more you're exposed to viruses that can stimulate all types of immune response, the better protected you're likely to be," said Dr. Carol Cardona, a UC Davis veterinarian and Cooperative Extension specialist, who partnered in the research with Dr. Zheng Xing.

"There does seem to be some level of antibody protection that people over 65 seem to have. There are some good things about getting older."

Call The Bee's Anita Creamer, (916) 321-1136.
The duo's findings will appear in the November edition of Emerging Infectious Diseases, a journal published by the Centers for Disease Control and Prevention.

In their research, Xing and Cardona surveyed data from earlier studies of the swine flu epidemic, identifying specific molecular sites – or epitopes – that strains of H1N1 found in California, New York and Texas share with the seasonal influenza A virus.

They theorize that those shared epitopes result in a degree of immunity to the new virus among people who have already been exposed to the seasonal flu, either through illness or through vaccination.

Their research also suggests that the epitopes involved with novel H1N1 exposure stimulate a kind of immunity in which T-cells attack and clear out pathogens. That's a different kind of immunity than one involving a protective antibody.

"It's really complicated, and it's hard to explain well in the media," said Cardona. "PacMan is the image that people generally use," she said in describing the kind of immunity she and Xing theorize. "But we're getting to the point where a lot of people don't know what PacMan is."

She cautions that people with some immunity may still come down with novel H1N1, but their symptoms are likely to be mild.

Both Xing and Cardona have also worked extensively in the past on avian flu research.