# 3536
Back in early May of this year I wrote a blog entitled Who Knew? New Flu about reports of a new mutation showing up in the seasonal H3N2 virus.
Maggie Fox, science reporter for Reuters, brought us some of the early details, some of which also appeared in ProMed-Mail.
Second strain of flu may complicate picture-study
06 May 2009 15:02:09 GMT
Source: Reuters
* Mutations seen in seasonal flu strain
* May have caused Canadian late-season outbreak
* May complicate picture in Mexico
By Maggie Fox, Health and Science Editor
WASHINGTON, May 6 (Reuters) - A second strain of influenza, one of the seasonal strains, may have mutated and may be complicating the picture in Mexico, Canadian researchers reported on Wednesday.
They have found a strain of the H3N2 virus that appears to have made a shift and could have complicated the flu picture in Mexico, epicenter of an outbreak of a new strain of the H1N1 swine flu virus.
One was seen in a traveler returning from Mexico, the team at the British Columbia Centre for Disease Control reported to Pro-MED, an online forum for infectious disease experts. And it may have been involved in an unusually late outbreak of flu in long-term care facilities this year.
As I stated in my blog at the time: This is, quite obviously, a story that bears watching.
Now Helen Branswell, intrepid medical and health reporter for the Canadian Press, brings us quite an extensive update.
H3N2, you may remember, tends to be a more serious seasonal flu than the H1N1 virus, and also seems to go after the elderly more aggressively as well.
A shift in the virus away from this year’s vaccine could prove serious, assuming that the novel H1N1 virus doesn’t completely supplant the seasonal viruses early in the fall and this mutation spreads.
Ms. Branswell’s report today is lengthy, detailed, and well worth following the link to read it in its entirety.
More flu vaccine woes: Possible mismatch with one part of seasonal flu shot
By Helen Branswell (CP) – TORONTO — Another storm may be brewing for the coming flu season: A component of the seasonal flu shot may not be well matched to the circulating viruses, potentially setting up what's known as a vaccine mismatch.
Some samples of the emerging new strain of H3N2 viruses show a substantially reduced response to antibodies generated by the corresponding virus in the seasonal vaccine, raising the possibility of significantly reduced protection in some cases.
Vaccine mismatches are bad at the best of times. More people get sick during flu seasons with mismatches. But a seasonal flu vaccine mismatch coinciding with a flu pandemic? That is no one's idea of a good time.
Dr. Allison McGeer groaned when she heard a new H3N2 variant is circulating in some parts of the Southern Hemisphere.
"It's going to be a long winter. I know that already," said McGeer, an influenza expert and head of infection control at Toronto's Mount Sinai Hospital.
"It's not going to be pleasant because ... it's going to be one big long influenza season, from some time in September until next May."
The new variant has been seen on a number of continents, though it still remains a minority member of the H3N2 family, according to experts at the World Health Organization and the U.S. Centers for Disease Control in Atlanta.
