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# 6489
Robert Roos of CIDRAP has an excellent report on a study – published on Aug 7th in The Journal of Infectious Diseases – that looks at pre-existing, and vaccine-induced immunity to the emerging H3N2v swine flu virus by age cohorts.
This serological study, conducted in Canada, is called :
Cross-reactive and vaccine-induced antibody to emerging swine influenza A(H3N2)v
Danuta M. Skowronski, Naveed Z. Janjua, Gaston De Serres3, Dale Purych, Vladimir Gilca, David W. Scheifele, Marc Dionne, Suzana Sabaiduc, Jennifer L. Gardy, Guiyun Li, Nathalie Bastien, Martin Petric, Guy Boivin and Yan Li
Below is Robert’s report on these findings, and as I’m hardly likely to improve upon his work, I’ll simply invite you to follow the link below and read:
Study: Children, middle-aged most vulnerable to variant H3N2
Robert Roos
News Editor
Aug 10, 2012 (CIDRAP News) – A serologic study from Canada suggests that children and middle-aged adults have little or no immunity to the swine-origin variant H3N2 influenza virus (H3N2v), but about half of adolescents and young adults have some degree of immunity as measured by antibody levels.
Robert’s story mentioned earlier studies with similar findings, and you can find details on them in these earlier blogs:
Last April in MMWR: Antibodies Cross-Reactive to Influenza A (H3N2) Variant Virus, we saw a study that found that children under the age of ten were practically devoid of antibodies to this virus, and were likely the most susceptible to infection.
A few months before, in Eurosurveillance: Older People May Be Susceptible To The H3N2v Virus), we saw evidence that the moderate levels of immunity detected in adolescent and young adult populations declined with age.
In other H3N2v news, Lisa Schnirring of CIDRAP has a excellent roundup, including the release of new interim clinician guidelines, the poor reliability of RIDTs (Rapid Influenza Detection Tests) with this virus, and an age breakdown of confirmed cases that now includes 10 adults.
CDC updates novel H3N2 info for clinicians
Lisa Schnirring
Aug 10, 2012 (CIDRAP News) – The US Centers for Disease Control and Prevention (CDC) today reported that it has received 153 reports of novel H3N2 infections (H3N2v) since illnesses started surfacing in the middle of July, nearly all of them in people who had contact with pigs or were around pigs at fairs.
In another development, the CDC issued new information on H3N2v for clinicians, including an evaluation of rapid influenza tests that found their sensitivity varies greatly, and the agency urged clinicians not to use negative results as the basis for treatment.
A blogger’s Note:
The slow emergence of this swine H3N2v virus into the human population is a fascinating story, and one that certainly deserves ongoing coverage. But at the same time, the last thing this story needs is unwarranted hype.
According to the CDC, this virus has not adapted well enough to human physiology to spark a pandemic. Nearly all confirmed cases appear to be the result of direct contact with an infected pig.
Sustained and efficient Human-to-Human transmission does not appear to be occurring at this time.
The caveat being, that over time, that could change.
For now, this virus is less a public health threat story and more an opportunity for us to learn how these types of viruses evolve in swine and (on rare occasion) seep into the human population.
A cautionary tale, if you will, on how nature’s laboratory is open 24/7 - constantly trying out new viral combinations - looking for an evolutionary advantage.
The dilemma, from my standpoint, is how to cover this story responsibly.
Rather than rush to post a blog every time we get an updated case count, for my own sanity, I’ve decided only to blog on the H3N2v virus when there is something more substantial to report.
This weekend I’ll explore the possibility of keeping a daily update `State Confirmed H3N2v Cases’ in my sidebar, at least until that becomes too unwieldy.
Even so, I’m sure H3N2v will get ample attention in these pages.
As we wait to see what this H3N2v virus ends up doing - between seasonal flu, bird flu, swine flu, seal flu, and bat flu, plus non-flu related stories - I’m confident there will be no shortage of topics to blog about.
