INFLUENZA (25): H3N2 SURVEILLANCE CANADA (BRITISH COLUMBIA), USA
A ProMED-mail posthttp://www.promedmail.org
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International Society for Infectious Diseaseshttp://www.isid.org
Date: Sat 7 Apr 2012
From: Danuta Skowronski
Re: Influenza in previously vaccinated children (USA Pacific Northwest)
In response to Dr. Wilson's ProMED posting of 6 Apr 2012 [Influenza (24): USA (Pacific NW) 20120406.1092588] querying variation in recent influenza A/H3N2 viruses away from the A/Perth/16/2009-like vaccine strain component of the seasonal trivalent influenza vaccine (TIV) since 2010-11 we would like to share findings from the sentinel surveillance system in Canada. Our findings for 2010-11, currently in press with Clinical Infectious Diseases , are also relevant to Dr. Wilson's queries for the 2011-12 season.
During the 2010-11 season, H3N2 viruses dominated among influenza detections in Canada and through phylogenetic analysis we identified two variant clades among strains circulating through the sentinel system . Viruses belonging to the A/Hong Kong/2121/2010 clade comprised nearly 90% and those belonging to the A/Victoria/208/2009 clade about 10% of sequenced strains. Based on phylogenetic analysis, few belonged to the A/Perth/16/2009 vaccine clade. Both variant clades showed substantial amino acid substitutions away from the vaccine strain in key antigenic sites, meeting genetic criteria for potential antigenic drift . Consistent with this, we measured suboptimal vaccine effectiveness for the H3N2 component of TIV that season .
For the 2011-12 northern and 2012 southern hemisphere influenza seasons, the A/Perth/16/2009 vaccine strain was retained as H3N2 component but has been replaced for the 2012-13 TIV by A/Victoria/361/2009 . The latter belongs to the A/Victoria/208/2009 clade we identified through sentinel surveillance in Canada in 2010-11, but has accumulated further mutations in antigenic sites .
In British Columbia, we have identified more significant contribution from the A/Victoria phylogenetic clade this season and given our geographic proximity, the same may also be anticipated in the USA Pacific Northwest. The most recent surveillance bulletin for Washington state reports that 10/22 H3N2 viruses characterized to date for 2011-12 show reduced titres with antiserum produced against the A/Perth/16/2009 vaccine strain . In that regard, suboptimal protection among vaccinated children this season may not be unexpected. It would be informative if the viruses detected by Dr. Wilson and colleagues were also strain characterized and sequenced to better elucidate their identity.
We should point out that influenza B has also been a contributor to influenza activity in British Columbia in recent weeks, with some lineage-level mismatch to the vaccine component noted among characterized strains, a finding also in common with Washington state .
1. Skowronski DM, Janjua NZ, De Serres G, et al. A sentinel platform to evaluate influenza vaccine effectiveness and new variant circulation, Canada 2010-11 season. Clinical Infectious Diseases [in press].
2. Bush RM, Bender CA, Subbarao K, Cox NJ, Fitch WM. Predicting the evolution of human influenza A. Science 1999;286:1921-5.
3. World Health Organization. Recommended composition of influenza virus vaccines for use in the 2012-2013 northern hemisphere influenza season. Available at: http://www.who.int/influenza/vaccines/v ... dation.pdf
4. Washington State Department of Health. Communicable Disease Epidemiology Influenza
Update. 2012 CDC Week 13 (3/25/12 - 3/31/12). Available at: http://www.doh.wa.gov/EHSPHL/Epidemiolo ... update.pdf
Danuta M Skowronski MD, FRCPC
Naveed Z Janjua MBBS, DrPH
Jennifer L Gardy PhD
Communicable Disease Prevention and Control Services
Suzana Sabaiduc BSc
Martin Petric PhD, FCCM
BC Public Health Microbiology and Reference Laboratory
BC Centre for Disease Control
Vancouver, British Columbia, Canada
Date: 7 Apr 2012
From: James M. Wilson V
We have report of another metropolitan hospital in the Pacific NW seeing influenza in previously vaccinated children.
Here in western Colorado, we saw the death of an elderly woman who had a prior medical history of chronic pulmonary disease. Both she and her husband were vaccinated for influenza, but the husband was the first to be infected, then the wife who later succumbed.
James M. Wilson V, M.D.
Delta County Memorial Hospital
Chief of Station
Ascel Bio Black Canyon Infectious Disease Forecast Station #1
[ProMED thanks Dr. Skowronski and colleagues for their communication supporting antigenic drift of influenza A strains as one of the factors responsible for infection in vaccinated individuals in the adjacent Northwestern USA, such as those noted by Dr. Wilson. - Mod.LM
A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/r/1*kk
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