The CDC report for Week 16, ending April 24, 2010 lists

• No states with widespread influenza activity.
  
• No states with regional influenza activity.
  
• Local influenza activity in two states (Alabama and South Carolina).
  
• Sporadic influenza activity in the District of Columbia, Guam, Puerto Rico, Arizona, Arkansas, California, Colorado,Florida, Georgia, Hawaii, Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri, Nevada, New Jersey, New Mexico, New York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Utah, Virginia, Washington, Wisconsin, and Wyoming.
  
• No influenza activity in Connecticut, Delaware, Idaho, Iowa, Kansas, Maine, Massachusetts, Montana, Nebraska, New Hampshire, North Carolina, North Dakota, Oregon, Rhode Island, South Dakota, Vermont, and West Virginia.
  
• The U.S. Virgin Islands and Alaska did not report.

From the WHO Pandemic (H1N1) 2009 update 98
Weekly virological surveillance update for 30 April 2010:
Overall influenza activity has remained at low levels in most parts of the world. In most countries where human infection of influenza virus was reported, the pandemic influenza A(H1N1) continues to be the predominating influenza A viruses subtyped (100% in Canada, and the United States and 74.2% globally). Seasonal A(H1N1) viruses were detected very sporadically in Russian Federation and China. Sporadic influenza A(H3N2) activity was reported from some countries including China, Japan and Russian Federation. Influenza B was reported as the predominating
influenza virus accounting for 72.0% of all influenza detections in Russian Federation, 88.5% in China, 92.9% in Sweden, 95,6% in Republic of Korea, 90% in Iran and 100% Mongolia. Increased sporadic influenza B activity has also been observed in some other countries. Based on FluNet reporting for the week from 11 April to 17 April 2010, the total number of specimens reportedly positive for influenza viruses by National Influenza Centres (NIC) from 29 countries was 1,451 Of these, 277 (19%) were typed as influenza A and 1,174 (81%) as influenza B. From the start of the pandemic in 19 April 2009 to 17 April 2010, based on
FluNet reporting by 85 countries, the total number of specimens reported positive for influenza by NIC laboratories was 19,919 *. Of these, 477,593 (77.0%) were pandemic A(H1N1), 8,801 (1.4%) were seasonal A(H1N1), 31,690 (5.1%) were A(H3N2), 73,603 (11.9%) were A (not subtyped) and 28,132 (4.5%) were influenza B.

The CDC Influenza Season update for Week 17, ending
May 1, 2010, reports

• No states with widespread influenza activity.
  
• No states with regional influenza activity.
  
• Local influenza activity in Alabama, Hawaii, Maine, and South Carolina.
  
• Sporadic influenza activity in the District of Columbia, Guam, Puerto Rico, Alaska, Arizona, Arkansas, California, Colorado, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, Mississippi, Missouri, Nevada, New Jersey, New Mexico, New York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Vermont, Virginia, and Wisconsin.
  
• No influenza activity in Connecticut, Delaware, Idaho, Iowa, Kansas, Massachusetts, Minnesota, Montana, Nebraska, New Hampshire, North Carolina, North Dakota, Oregon, Rhode Island, South Dakota, Utah, Washington, West Virginia, and Wyoming).
  ◦The U.S. Virgin Islands did not report.

WHO's Pandemic (H1N1) 2009 - update 99, on 7 May 2010 says, as of 2nd May, more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18001 deaths.

The CDC Update for Week 18, ending May 8, 2010, lists

• No states with widespread influenza activity.
  
• No states with regional influenza activity.
  
• Local influenza activity in Hawaii.
  
• Sporadic influenza activity in Guam, Puerto Rico, Alaska, Arizona, California, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Missouri, Nevada, New York, Ohio, Pennsylvania, Tennessee, Texas, Virginia, and Wisconsin.
  
• No influenza activity in the District of Columbia, Alabama, Arkansas, Delaware, Idaho Iowa, Maine, Minnesota, Mississippi, Montana, Nebraska, New Hampshire, New Jersey, New Mexico, North Carolina, North Dakota, Oklahoma, Oregon, Rhode Island, South Carolina, South Dakota, Utah, Vermont, Washington, West Virginia, and Wyoming.
  
• The U.S. Virgin Islands did not report.

WHO's Pandemic (H1N1) 2009 - update 99 for 7 May 2010—As of 2nd May, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18001 deaths.

The CDC update for Week 19, ending May 15, 2010, lists

• No states with widespread influenza activity.
  
• No states with regional influenza activity.
  
• Local influenza activity in Hawaii.
  
• Sporadic influenza activity in Puerto Rico, Arizona, California, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Missouri, Nevada, New Jersey, New York, South Carolina, Texas, and Virginia.
  
• No influenza activity in the District of Columbia, Guam, Alabama, Alaska, Arkansas, Delaware, Idaho, Iowa, Maine, Massachusetts, Michigan, Minnesota, Mississippi, Montana, Nebraska, New Hampshire, New Mexico, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Dakota, Tennessee, Utah, Vermont, Washington, Wisconsin, West Virginia, and Wyoming.
  
• The U.S. Virgin Islands did not report.

The WHO Update 100, on May 14, 2010—Reports, worldwide, as of 9 May, more than 18036 deaths (cumulative) from H1N1 influenza.

     This CDC Influenza update for Week 20, ending May 22, 2010,is the final report of the 2009-2010 season. The first weekly report of the 2010-2011 season (week 40, ending October 9, 2010) will be published on October 15, 2010.
     During week 20, the following influenza activity was reported:

• No states with widespread influenza activity.
  
• No states with regional influenza activity.
  
• Local influenza activity in Hawaii.
  
• Sporadic influenza activity was reported by Guam, Puerto Rico, California, Florida, Illinois, Kentucky, Louisiana, Maryland, Missouri, Nevada, New Jersey, New York, Texas, Virginia, and West Virginia.
  
• No influenza activity in the District of Columbia, Alabama, Alaska, Arkansas, Colorado, Connecticut, Delaware, Georgia, Indiana, Iowa, Kansas, Maine, Massachusetts, Michigan, Minnesota, Mississippi, Montana, Nebraska, New Hampshire, New Mexico, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Utah, Vermont, Washington, Wisconsin, and Wyoming.
  
• The U.S. Virgin Islands, Arizona and Idaho did not report.

WHO's Update #101:
     As of 16 May, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18097 deaths in all.

     Flu shots conferring immunity to influenza B, as well as the A/H1N1 and the A/H3N2 strains are now available, nation-wide, on a walk-in basis, at Walgreen's and CVS pharmacies. I had my shot six hours ago with no bad effect beyond a slight dull ache at the injection site.
Seán

     On the second day pain from the flu shot increased so I took some Advil. That worked but another dose was needed after each eight hour interval. Most Websites on the subject of flu injection pain say pain-killers are OK to use, but I found one that says they prevent immunity development! The article seems credible to me, so I quit taking Advil. Instead I use cold compresses, which are working well enough.
Seán

Sean,

I'm sure the answer is somewhere on this thread, I just won't be able to find it no doubt. Question: The immunity lasts for a given period of time right? IT peaks and then begins to wane. Therefore, is it not possible to take the vaccine too early if the peak flu period is predicted in February or March? We got ours very late last year when it became widely available.

What's your take on this?

Peachy

Peachy,
     The CDC answers this question:

Does getting vaccinated against flu early in the season pose a risk that immunity may wane before the end of the season?

No. Flu vaccination provides protection against the influenza strains contained in the seasonal vaccine for the entire season. Vaccination can begin as soon as vaccine becomes available.
Seán

The Flu Map for the week ending October 23, 2010 shows sporadic cases in the populous states, local cases in Texas, regional in Hawaii and negligible incidence elsewhere in the USA. Expect flu to spread rapidly when holiday shopping and group festivities provide opportunities for exposure.
Seán

     Excepting Vermont, which was still untainted as of December 18, flu is now active in all states. The Eastern seaboard and the Gulf states have been hit the hardest.
Seán

     The number of positive tests for flu was sharply down on week 1 (ending 01/08/2011). Probably that does not mean this flu season will be a mild one. One may hope, however.
Seán

     The incidence of flu and flu-like illnesses remained low in the USA on January 15, 2011.
Seán

     During Influenza Season Week 3 ending January 22, 2011 the
incidence of flu increased, but remained below the epidemic level.

During Influenza Season Week 4, ending January 29, 2011,

• Widespread influenza activity was reported by 30 states (Alabama, Alaska, Arizona, Arkansas, Colorado, Connecticut, Florida, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Mississippi, Nevada, New Mexico, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Vermont, Virginia, West Virginia, and Wyoming).
  
• Regional influenza activity was reported by 15 states (California, Georgia, Idaho, Iowa, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Jersey, North Dakota, Rhode Island, South Dakota, and Wisconsin).
  
• Local influenza activity was reported by the District of Columbia and Washington.
  
• Sporadic influenza activity was reported by Puerto Rico, the U.S. Virgin Islands, Delaware, Hawaii, Oregon, and Utah.
  
• Guam reported no influenza activity.

For Influenza Season Week 5, ending February 5, 2011

• Widespread influenza activity was reported by Alabama, Alaska, Arizona, Arkansas, Colorado, Connecticut,
  Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Minnesota,
  Mississippi, Nebraska, Nevada, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma,
  Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Vermont, Virginia, West Virginia,
  Wisconsin, and Wyoming. (Thirty-seven states)
  
• Regional influenza activity was reported by California, Idaho, Iowa, Michigan, Missouri, Montana,
  New Hampshire, North Dakota, and Washington. (Nine states)
  
• The District of Columbia reported local activity.
  
• Sporadic influenza activity was reported by Delaware, Hawaii, Oregon, and Utah Guam, Puerto Rico, and
  the U.S. Virgin Islands.

During week 6 (February 6-12, 2011), influenza activity
in the United States remained elevated.

• Of the 9,448 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and
  Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 3,306 (35.0%) were positive for influenza.
  
• Widespread influenza activity was reported by 36 states: Alabama, Alaska, Arizona, Arkansas, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Mexico New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Vermont, Virginia, West Virginia, Wisconsin, and Wyoming.
  
• Regional influenza activity was reported by 10 states: California, Idaho, Kentucky, Mississippi, Nevada, New Jersey, North Dakota, South Dakota, Utah, and Washington.
  
• The District of Columbia reported local activity.
  
• Sporadic influenza activity was reported by Delaware, Hawaii, Oregon, Puerto Rico, and the U.S. Virgin Islands.
  
• Guam reported no influenza activity.

     The flu season typically ends in March, which is only eight days away!
Seán

During week 8 (February 20-26, 2011)

• Eighteen states (Alabama, Arkansas, Colorado, Idaho, Indiana, Louisiana, Missouri, Nebraska, New Jersey, New Mexico, North Carolina, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, and West Virginia) experienced high ILI activity.
  
• Six states (Hawaii, Kansas, Kentucky, Michigan, New York, and Washington) experienced moderate ILI activity.
  
• New York City and 16 states (Alaska, Arizona, California, Florida, Georgia, Illinois, Maryland, Massachusetts, Minnesota, Mississippi, Montana, Nevada, North Dakota, South Dakota, Utah, and Wisconsin) experienced low ILI activity.
  
• Minimal ILI activity was experienced by 10 states (Connecticut, Delaware, Iowa, Maine, New Hampshire, Ohio, Oregon, Rhode Island, Vermont, and Wyoming).
  
• The District of Columbia had insufficient data to calculate an activity level.

Influenza Season Week 9 ending March 5, 2011 saw

• Ten states (Alabama, Alaska, Arkansas, Idaho, Indiana, Nevada, New Mexico, Texas, Virginia, and West Virginia) with high ILI activity.
  
• Twelve states (California, Colorado, Hawaii, Louisiana, Missouri, Nebraska, North Dakota, Oklahoma, South Carolina, South Dakota, Tennessee, and Wisconsin) with moderate ILI activity.
  
• Nine states (Georgia, Illinois, Kansas, Kentucky, Massachusetts, New Jersey, North Carolina, Rhode Island, and Wyoming) with low ILI activity.
  
• Minimal ILI activity in New York City and 19 states (Arizona, Connecticut, Delaware, Florida, Iowa, Maine, Maryland, Michigan, Minnesota, Mississippi, Montana, New Hampshire, New York, Ohio, Oregon, Pennsylvania, Utah, Vermont, and Washington).
  
• The District of Columbia had insufficient data to calculate an activity level.

During week 10 (March 6-12, 2011), influenza activity in the United States decreased.
These ILI levels were reported:

• Four states (Alabama, Idaho, Missouri, and North Dakota) experienced high ILI activity.
  
• Six states (Alaska, Nevada, New Jersey, Oklahoma, Texas, and Virginia) experienced moderate ILI activity.
  
• Eleven states (California, Indiana, Kansas, Louisiana, Massachusetts, New Mexico, New York, South Carolina, Utah, West Virginia,
  and Wisconsin) experienced low ILI activity.
  
• Minimal ILI activity was experienced by New York City and 28 states (Arizona, Arkansas, Connecticut, Delaware, Florida, Georgia,
  Hawaii, Illinois, Iowa, Kentucky, Maine, Maryland, Michigan, Minnesota, Mississippi, Montana, Nebraska, New Hampshire, North Carolina,
  Ohio, Oregon, Pennsylvania, Rhode Island, South Dakota, Tennessee, Vermont, Washington, and Wyoming).
  
• The District of Columbia and one state (Colorado) had insufficient data to calculate an activity level.

During Influenza Season Week 11 ending March 19, 2011, the following ILI activity
levels were experienced:

• One state (Idaho) experienced high ILI activity.
  
• Two states (West Virginia and Wisconsin) experienced moderate ILI activity.
  
• Eleven states (Arkansas, Hawaii, Illinois, Indiana, Massachusetts, Nevada, New Mexico,
  North Dakota, Oklahoma, Utah, and Virginia) experienced low ILI activity.
  
• Minimal ILI activity was experienced by New York City and 35 states (Alabama, Alaska,
  Arizona, California, Connecticut, Delaware, Florida, Georgia, Iowa, Kansas, Kentucky,
  Louisiana, Maine, Maryland, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska,
  New Hampshire, New Jersey, New York, North Carolina, Ohio, Oregon, Pennsylvania, Rhode Island,
  South Carolina, South Dakota, Tennessee, Texas, Vermont, Washington, and Wyoming).
  
• The District of Columbia and one state (Colorado) had insufficient data to calculate an activity level.

During Influenza Season Week 12 ending March 26, 2011
these following ILI activity levels were reported:

• One state (Idaho) experienced high ILI activity.
  
• Three states (Alaska, Illinois, and North Dakota) experienced low ILI activity.
  
• Minimal ILI activity was experienced by New York City and 46 states (Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming).
  
• The District of Columbia had insufficient data to calculate an activity level.

During Influenza Season Week 13 ending April 2, 2011 minimal ILI activity was experienced by New York City and all 50 states. The District of Columbia had insufficient data to calculate an activity level.