MONDAY, Oct. 18 (HealthDay News) -- Canadian researchers say they do not expect the H1N1 virus -- the so-called swine flu -- to be very severe this year, although they are recommending that everyone over the age of 50, especially those with chronic health conditions, get immunized this fall.
Researchers in British Columbia examined the results of blood tests given to 1,127 people in the province both before and after the 2009 pandemic. Before the pandemic, less than 10 percent of children showed signs of antibodies, which are the "soldiers" in the immune system that develop resistance to specific germs. By contrast, more than three-quarters of people over the age of 80 had the antibodies, suggesting they'd been exposed to the virus before.
This helps explain why children were so severely affected by H1N1 compared to older people, the study authors noted.
In contrast, after the pandemic, 70 percent of people under the age of 20 showed signs of this type of protection, according to the report published online Oct. 18 in the CMAJ.
"The higher percentage with seroprotection [antibodies in blood] we observed in the young may have resulted from higher pandemic H1N1 infection rates and earlier prioritization of pandemic H1N1 vaccine to young children," said study co-author Dr. Danuta Skowronski, of the BC Centre for Disease Control and University of British Columbia, in a news release from the journal's publisher.
The researchers wrote that enough people appear to be protected that "these findings reassure against the likelihood of a substantial third pandemic H1N1 wave during the 2010-2011 season, unless there is a significant waning of antibody or change in the virus."
They also found that "adults 50 to 79 years exhibited the lowest seroprotection and also remain at higher risk of severe outcomes if infected. Our findings support a shift from the prioritized immunization of the young that occurred
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