A/Brisbane and current flu season

[JohnW]

I posted this comment under the CDC news item, but thought I'd escalate it for action

Quote:
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Influenza A (H3) [19]

• Four viruses were characterized as A/Wisconsin/67/2005-like, the influenza A (H3) component of the 2007-08 influenza vaccine for the Northern Hemisphere.
• Fourteen viruses were characterized as A/Brisbane/10/2007-like. A/Brisbane/10/2007 is a recent antigenic variant which evolved from A/Wisconsin/67/2005-like. A/Brisbane/10/2007-like virus is the recommended influenza A (H3) component for the 2008 Southern Hemisphere vaccine.
• One virus showed somewhat reduced titers with antisera produced against A/Wisconsin/67/2005 and A/Brisbane/10/2007.

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I presume that A/Brisbane is the same strain that caused such a severe flu season in Australia. If 14 out of 19 specimens in the US were A/Brisbane, does this imply the US is going to have a severe flu season this year as well? Given that the current tri-valent vaccine did not include A/Brisbane, does this imply that those who received flu shots would not have protection against A/Brisbane? Could A/Brisbane also be behind some of what we are seeing in Egypt?

(Still trying to figure this stuff out)

[gsgs]

Re: A/Brisbane and current flu season

last year's circulating strains were also Brisbane-like.
Almost no H3 in Europe so far, most is H1N1 or B,
I'll check USA ...
influenza USA 5.Jan.2008
7.2&#37;of samples were positive for flu
307 were H1
94 were H3
1051 were flu-A, H?
222 were flu-B

so, 3/4 of flu-A are H1 so far. However, last year it was similar and H3 came later.

http://www.cdc.gov/flu/weekly/weeklyarchives2007-2008/data/whoAllregt01.htm

http://www.cdc.gov/flu/weekly/weeklyarchives2006-2007/data/whoAllregt20.htm

I assume there are other reasons for the severety of Australian flu-season.

This has nothing to do with H5N1 in Egypt

[Giuseppe]

Re: A/Brisbane and current flu season

This is the latest EISS Influenza Activity Bulletin:
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4) [SEASONAL INFLUENZA, EUROPEAN UNION, EISS, UPDATES] EISS - Weekly Electronic Bulletin - Week 1 : 31/12/2007-06/01/2008 - 11 January 2008, Issue N? 248 - Increased levels of influenza activity in seven European countries and low levels across the rest of Europe

Summary:

There is currently increased influenza activity in England, Ireland, Italy, Luxembourg, Slovenia, Spain and Switzerland.

In France and Portugal levels of influenza activity are around the baseline threshold.

All other countries reported low levels of influenza activity.

Of the total virus detections since week 40/2007 (N=1475), 82% were influenza A of which about 95% were of the H1 subtype.

Epidemiological situation - week 01/2008:

For the intensity indicator, the national network levels of influenza-like illness (ILI) and/or acute respiratory infection (ARI) were medium in England, Ireland, Italy, Luxembourg, Slovenia, Spain and Switzerland, whilst they remained low or became low again in 19 other countries that reported this indicator.

For the geographical spread indicator, three countries (England, Spain and Switzerland) reported regional influenza activity, five countries local activity, 13 countries sporadic activity and five countries reported no influenza activity. Definitions for the epidemiological indicators can be found here.

Cumulative epidemiological situation - 2007-2008 season (since week 40/2007):

So far this season, the consultation rates for ILI and/or ARI have been at levels usually seen outside the seasonal influenza peak period (i.e. below or at the national baseline threshold) in most countries in Europe.

A medium intensity of influenza activity (i.e. consultations rates were above the national baseline threshold) was first reported in Bulgaria (in week 48/2007), Austria (50/2007), Northern Ireland (50/2007) and Spain (week 51/2007).

In week 01/2008 intensity remained at medium level in Spain and England, Ireland, Italy, Luxembourg, Slovenia and Switzerland started reporting a medium intensity.

Virological situation - week 01/2008:

The total number of respiratory specimens collected by sentinel physicians in week 01/2008 was 643, of which 143 (22%) were influenza virus positive; 44 (31%) type A not subtyped, 79 (55%) type A subtype H1 [of which 23 were A(H1N1)], one (1%) type A subtype H3 and 19 (13%) type B.

In addition, 187 influenza virus detections were reported from non-sentinel sources (e.g. specimens collected for diagnostic purposes in hospitals), of which 130 (70%) were type A not subtyped, 28 (15%) type A subtype H1 [of which 14 were A(H1N1)] and 29 (15%) type B.

Cumulative virological situation - 2007-2008 season (since week 40/2007):

Based on (sub)typing data of all influenza virus detections since week 40/2007 (N=1475; sentinel and non-sentinel data), 599 (41%) were type A not subtyped, 588 (40%) were A(H1), 28 (2%) were A(H3) and 260 (17%) were B.

Based on the antigenic and/or genetic characterisation of 268 influenza viruses, three were A/New Caledonia/20/99 (H1N1)-like, 216 were A/Solomon Island/3/2006 (H1N1)-like, two were A/Wisconsin/67/2005 (H3N2)-like, seven were A/Brisbane/10/2007 (H3N2)-like, 24 were B/Florida/4/2006-like (B/Yamagata/16/88 lineage) and 16 were B/Malaysia/2506/2004-like (B/Victoria/2/87 lineage) (click here).

Comment:

Consultation rates for ILI and ARI reported are affected by seasonal holidays.

Since this report is based on a week which includes New Year?s Day (1 January), usual patterns of access to primary care and patient swabbing procedures were probably disrupted and the reported consultation rates could be lower than an equivalent non-holiday week.

Hence reported rates should be interpreted cautiously.

Despite this, the current data indicate that confirmed influenza activity is increasing in 16 European countries (see intensity map) and a further increase in influenza activity in the coming weeks can be expected.

Countries reporting a medium intensity were located in Northern (England and Ireland), Southern (Italy, Slovenia, Spain) and Western (Luxembourg and Switzerland) Europe [according to the UN Geographical Regions].

In the rest of Europe, the ILI and/or ARI consultation rates are currently below the national baseline level but if the pattern of previous seasons is repeated it is likely that some or many of those countries will also see rises.

Overall, for Europe as a whole, 82% of total virus detections since week 40/2007 (N=1475) have been influenza A, of which 95% were of the H1 subtype (calculation excludes the type A not subtyped virus detections).

The characterisation data reported to EISS since week 40/2007 indicate that there seems to be a good match between the circulating A(H1) virus and the corresponding vaccine strain A/Solomon Island/3/2006 which is included in the 2007-2008 vaccine (click here).

Background:

The Weekly Electronic Bulletin presents and comments influenza activity in the 31 European countries that are members of EISS.

In week 01/2008, 26 countries reported epidemiological data and 28 countries reported virological data to EISS.

The spread of influenza virus strains and their epidemiological impact in Europe are being monitored by EISS in collaboration with the WHO Collaborating Centre in London (United Kingdom) and the European Centre for Disease Prevention and Control in Stockholm (Sweden).

Other bulletins: To view national/regional bulletins in Europe and other bulletins from around the world, please click here.


Network comments (where available)

* Italy - Five A/H1N1 and 1 B influenza viruses have been detected during the last two weeks.


* Serbia - In the 52nd week of 2007 (28.12.2007), we received 3 nose/throat samples obtained from children aged 6-8 years, all from Belgrade. Real-time results confirmed Inf A (H1) infection on the same day, but the results were not officially recorded until it was confirmed in tissue culture in the 1st week of 2008.


* Sweden - We are courrently transfering our influensa reporting to a new reporting system from week 1/ 2008.We have therefore a substantial delay in reporting influensa activity for week 1/ 2008 due to some technical problem. The clinical data is not yet complete. The influenza activity is now increasing in Sweden. The RSV activity increases as well.


*Switzerland - Medical consultation for ILI bypassed threshold this week. Influenza A (H1N1) virus are mainly detected. Some influenza B virus are also detected.
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[JohnW]

Re: A/Brisbane and current flu season

"Based on the antigenic and/or genetic characterisation of 268 influenza viruses, three were A/New Caledonia/20/99 (H1N1)-like, 216 were A/Solomon Island/3/2006 (H1N1)-like, two were A/Wisconsin/67/2005 (H3N2)-like, seven were A/Brisbane/10/2007 (H3N2)-like, 24 were B/Florida/4/2006-like (B/Yamagata/16/88 lineage) and 16 were B/Malaysia/2506/2004-like (B/Victoria/2/87 lineage)"

Now that really surprises me. The clip I posted above was from the CDC for the US. I always thought the predominate A clade was H3N2, with H1N1 a very minor player each year. You are suggesting 95% of the cases in Europe this year are H1N1. What are the implications of this, if any?

[gsgs]

Re: A/Brisbane and current flu season

some years are H1N1 dominated, some H3N2.
H1N1-years are usually milder.

last year H3N2 comes later than H1N1 so this 95%
can still change to 50% or such.