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Table 1 Relationship between duration week from the lowest WSD week to the peak week and proportions of circulated type/subtype of influenza virus

From: Novel measurement of spreading pattern of influenza epidemic by using weighted standard distance method: retrospective spatial statistical study of influenza, Japan, 1999–2009

Seasons Lowest WSD week (a) Peak week* (b) Duration between (a) and (b), weeks Prevalence of type or subtype of influenza virus in early phase of the season†
      A/H3N2   A/H1N1   B
1999/2000 51st, 1999 5th, 2000 6 45.2% A/Sydney/5/97 54.8% A/New Caledonia/20/99 0.0% -
2000/2001 48th, 2000 10th, 2001 14 14.3% A/Panama/2007/99 43.4% A/New Caledonia/20/99 42.3% B/Sichuan/379/99
2001/2002 1st, 2002 8th, 2002 7 38.3% A/Panama/2007/99 51.2% A/New Caledonia/20/99 10.5% B/Shandong/7/97
2002/2003 52nd, 2002 5th, 2003 5 85.4% A/Fujian/411/2002 0.0% -‡ 14.6% B/Shandong/7/97
2003/2004 52nd, 2003 6th,2004 6 98.6% A/Fujian/411/2002 0.1% - 1.3% B/Shanghai/361/2002
2004/2005 42nd, 2004 9th, 2005 20 35.4% A/California/7/2004 3.7% A/New Caledonia/20/99 60.9% B/Shanghai/361/2002
2005/2006 6th, 2006 5th,2006 -1§ 83.0% A/Wisconsin/67/2005 16.1% A/New Caledonia/20/99 0.9% B/Malaysia/2506/2004
2006/2007 49th, 2006 11th, 2007 14 49.0% A/Brisbane/10/2007 9.2% A/New Caledonia/20/99 A/Solomon Islands/3/2006 41.8% B/Malaysia/2506/2004
2007/2008 39th, 2007 5th, 2008 18 5.4% A/Brisbane/10/2007 93.0% A/Solomon Islands/3/2006 1.6% B/Florida/4/2006
2008/2009 44th, 2008 5th, 2009 13 28.1% A/Brisbane/10/2007 61.8% A/Solomon Islands/3/2006 10.1% Brisbane/60/2008
  1. * The peak week of influenza cases.
  2. † See method section about a definition of “early phase”.
  3. ‡ Data not available.
  4. § Minus value of duration between means that peak week came earlier than the lowest WSD week.
  5. After A/New Caledonia/20/99 was circulated, A/Solomon Islands/3/2006 was equivalently circulated in 2006/2007 season.