National Visits Influenza-like Illnesses: March 24, 2012

2012 3-24 ILI 570

This graph posted by the Centers for Disease Control and Prevention (CDC) on March 30, 2012 shows visits for influenza-like illness (ILI) nationwide during the week ending March 24. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

Flu activity has fallen below the baseline level of 2.4% this week after briefly peaking at 2.4% two weeks ago. This remains a very slow influenza season, with very little activity reported in most regions of the country. It is unlikely that flu activity will expand significantly from this late point in the season.

  Click here to get more detailed information from CDC.

How is this curve constructed?       Each week a group of “sentinel providers” around the country reports to CDC on how many of their patients in emergency departments and clinics have illnesses that match the CDC case definition for “influenza-like illness”, or ILI. ILI is defined as fever PLUS either cough or sore throat that cannot be attributed to another cause such as Strep throat (i.e. Strep throat is NOT an ILI). This data is collected at CDC and posted.

What does the curve mean?     The ILI curve does not tell us the total number of people with flu, it tells us what proportion of patients around the country have an illness like the flu. ILI occurs at a low background rate of 1-2%  throughout the year, even when flu is not circulating.  This background rate of ILI is due to other viruses such as  Rhinovirus (cold virus), RSV, and Parainfluenza. Years of experience has shown that when the ILI curve rises above its baseline and peaks 4-8 weeks later, it closely correlates with actual influenza activity as determined by more tedious and expensive viral cultures. Thus, the ILI curve provides a convenient way to track the progress of our yearly influenza season, which almost always arrives between December and March. During the winter (i.e., flu season), most people with ILI actually do have the flu. During the summer and autumn months, patients with ILI almost invariably are infected with other respiratory viruses. The summer of 2009 was a major exception to this rule, reflecting the first wave of pandemic flu due to 2009 H1N1 during the US summer months.

*******************************************************************************

Past Updates 2011-2012 Season

Feb 5, 2012

This graph posted by the Centers for Disease Control and Prevention (CDC) on Feb 5, 2012 shows visits for influenza-like illness (ILI) nationwide during the week ending Jan 28. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

Flu remails well below baseline ILI activity of 2.4%. Activity above the baseline generally heralds the beginning of the flu season. There has been a slow but steady rise in ILI over the past 2-3 months, most of which is due to the presence of other respiratory viurses that mimic flu.

Jan 27, 2012

This graph posted by the Centers for Disease Control and Prevention (CDC) on Jan 27, 2012 shows visits for influenza-like illness (ILI) nationwide during the week ending Jan 21. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

The graph shows that there has been a slow but steady increase in ILI cases nationwide beginning 2-3 months ago. However, we are not close to the threshold level of 2% that generally heralds the beginning of the nationwide flu season. Over the past 30 years, about half of the flu seasons have begun in January or February. We can expect this curve to begin a more rapid rise over the next 2-4 weeks.

**********************************************************************************

Past Updates 2010-2011 Season

March 2011

This graph posted by the Centers for Disease Control and Prevention (CDC) on Jan 27, 2012 shows visits for influenza-like illness (ILI) nationwide during the week ending Jan 21. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

The graph shows sharp declines in ILI activity for two consecutive weeks. It appears that we have passed the peak in ILI for this flu season, but we are still above the national baseline of 2 1/2% that serves as a marker for “Flu Season”. We should continue to see a steady decline as the flu season winds down over the next 2-6 weeks.

 ILI cases nationwide began trending steadily upward starting in week 35 and crossed the ILI threshold of 2.5% in late December. An ILI rate at that level early in the winter months generally heralds the beginning of the flu season. However, the early season surge in influenza B declined after mid-December, and influenza A has become the predominant type since then. This has given us the appearance of a two-part flu season. Visits for ILI cases are currently at approximately 3% in clinics and emergency departments across the country, only slightly above the national baseline. At this point in the season, this indicates that flu will be gone from our communities soon.

The flu season is nearing an end but not yet over.

Feb 25 

This graph posted by the Centers for Disease Control and Prevention (CDC) on Feb 25, 2011 shows visits for influenza-like illness (ILI) nationwide during the week ending Feb 19. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

There has been a distinct pause in the rise in ILI over the past three weeks. We are probably nearing the peak of activity for the season.

 ILI cases nationwide began trending steadily upward starting in week 35 and crossed the ILI threshold of 2.5% in late December. An ILI rate at that level early in the winter months generally heralds the beginning of the flu season. However, the early season surge in influenza B declined after mid-December, and influenza A has become the predominant type since then. This has given us the appearance of a two-part flu season. Visits for ILI cases are currently at approximately 5% in clinics and emergency departments across the country. Historically, this is a relatively low rate.

We are in the midst of the yearly flu epidemic. There are more states reporting widespread activity this week than at any time during the 2010-2011 season. We can expect the decline in flu activity to begin in the next 2-4 weeks.

Feb 18, 2011

 This graph posted by the Centers for Disease Control and Prevention (CDC) on Feb 18, 2011 shows visits for influenza-like illness (ILI) nationwide during the week ending Feb 12. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

There was a slight pause in the upward trajectory of the national ILI curve this week. It is too early to tell if we have arrived at our peak of activity for the season, or if there will be a continued rise.

ILI cases nationwide began trending steadily upward starting in week 35 and crossed the ILI threshold of 2.5% in late December. An ILI rate at that level early in the winter months generally heralds the beginning of the flu season. However, the early season surge in influenza B declined after mid-December, and influenza A has become the predominant type since then. This has given us the appearance of a two-part flu season. Visits for ILI cases are currently at approximately 5% in clinics and emergency departments across the country. Historically, this is a relatively low rate.

Flu season is here, although in many states it is still not widespread. Even in states where it is widespread, flu activity appears to be moderate.

Feb 11, 2011

 This graph posted by the Centers for Disease Control and Prevention (CDC) on Feb 11, 2011 shows visits for influenza-like illness (ILI) nationwide during the week ending Feb 5. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

The winter season increase in ILI cases paused during the Christmas and New Year holidays, but has increased through every week of the new year. The steady rise will likely continue for several more weeks before peaking in late February or early March.

ILI cases nationwide began trending steadily upward starting in week 35 and crossed the ILI threshold of 2.5% in late December. An ILI rate at that level early in the winter months generally heralds the beginning of the flu season. However, the early season surge in influenza B declined after mid-December, and influenza A has become the predominant type since then. This has given us the appearance of a two-part flu season. Visits for ILI cases are currently at approximately 5% in clinics and emergency departments across the country. Historically, this is a relatively low rate that is likely to rise as the season progresses.

Jan 29, 2011

This graph posted by the Centers for Disease Control and Prevention (CDC) on January 29, 2011 shows visits for influenza-like illness (ILI) nationwide during the week ending Jan 22. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

The winter season increase in ILI cases paused during the Christmas and New Year holidays, but has increased again for the past two weeks. We are likely to see steady rises again in the coming weeks.

ILI cases nationwide began trending steadily upward starting in week 35 and crossed the ILI threshold of 2.5% in late December. An ILI rate at that level in the winter months generally heralds the beginning of the flu season. Increasing isolation of influenza, especially influenza B, was also noted starting in November, leading many to believe we would see an early flu season. However, influenza B has clearly waned over the past 4 weeks while influenza A (H3N2) is on the rise.

Flu season is here, and the rapid surge in influenza cases that is typical of the yearly epidemics is likely to occur in the next  2-4 weeks.

 Jan 21, 2011

This graph posted by the Centers for Disease Control and Prevention (CDC) on January 21, 2011 shows visits for influenza-like illness (ILI) nationwide during the week ending Jan 15. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

The winter season increase in ILI cases paused two weeks ago nationally. There was a slight decrease during the Christmas and New Year holidays, and a slight increase again in the past week. We are likely to see steady rises again in the coming weeks.

ILI cases nationwide began trending steadily upward starting in week 35 and crossed the ILI threshold of 2.5% in late December. An ILI rate at that level in the winter months generally heralds the beginning of the flu season. Increasing isolation of influenza, especially influenza B, was also noted starting in November, leading many to believe we would see an early flu season. However, the spread of flu in the past month has been inconsistent around the country, and in the case of Georgia and several other states, activity has even decreased over the past several weeks.

Flu season is fast approaching, but we are probably a number of weeks away from the rapid surge in influenza cases that is typical of the yearly epidemics.

Jan 15, 2011

 This graph posted by the Centers for Disease Control and Prevention (CDC) on January 13, 2011 shows visits for influenza-like illness (ILI) nationwide during the week ending Jan 7. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

ILI cases nationwide began trending steadily upward starting in week 35 and crossed the ILI threshold of 2.5% in late December. An ILI rate at that level in the winter months generally heralds the beginning of the flu season. Increasing isolation of influenza, especially influenza B, has also been noted since November, leading many to believe we would see an early flu season. However, ILI rates have declined nationally for the past two weeks after peaking on Dec 24 at 2.7%.

The US Southeast (CDC Region 4) continues to be the focal point for flu activity in the US so far this season. Region 4 is the only region in the country with ILI rates above the national threshold. It does appear that the rise in flu activity noted in Region 4 in early December has declined somewhat but the region continues to have more states reporting widespread activity than any other region.

Flu season is fast approaching, but we are probably a number of weeks away from the significant surge in influenza cases that is typical of the yearly epidemics.

Jan 7, 2011

ILI activity has been rising steadily since week 35, and has been slightly above the seasonal baseline rate of 2.5% for the past two weeks. A rise in the ILI rate above the seasonal baseline generally heralds the beginning of the influenza season. However, as the weekly map from CDC shows (see G-LINE home page), flu activity is quite variable around the country. Some regions in the US are seeing significant numbers of influenza patients, but many regions are not. The US Southeast region has reported regional or widespread activity for the past 4-6 weeks and appears to be the focal point for the annual influenza season so far.

Dec 23, 2010

This graph posted by the Centers for Disease Control and Prevention (CDC) on December 23 2010 shows visits for influenza-like illness (ILI) nationwide during the week ending Dec 18. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

ILI activity appears to be on the rise, although the national ILI rate has not yet crossed the threshold that would indicate the beginning of flu season. Only one region in the US, the Southeast Region, is reporting ILI levels above baseline.

Dec 10, 2010

This graph posted by the Centers for Disease Control and Prevention (CDC) on December 10 2010 shows visits for influenza-like illness (ILI) nationwide during the week ending Dec 4. There is generally a  one-week lag between data collection and release to the public. The units at the bottom of the graph indicate the date by week of the year.

Flu activity remains low throughout the United States. There had been several weeks of increased activity in the Southeast with a focus in Georgia starting in mid-November, but activity in this region has declined in the past week. All 10 US regions are reporting activity well below their baseline, with most states reporting only sporadic activity.

Flu season has not yet arrived.

It is not quite easy to receive funds through other external resources, ordinarily to deal with health care needs. What points families think when they are going to order any drugs? Nowadays ten percent of men aged 40 to 70 were unable to maintain an erection during sex. It affects men of all races. Matters such as viagra ingredients are very pops for last year. Who have to not use Viagra? What do you should know about viagra composition? Also, think about sildenafil ingredients. The signs of sexual disorders in men turn on incredibility to reach an orgasm despite adequate sexual stimulation. Get medic help if you have any of these signs of a side effect to this medication. If the drug you are taking is not approved, your sex therapist can prescribe another medication.

Leave a Reply

cdc situation overview

Each week CDC analyzes information about influenza disease activity in the United States and publishes findings of key flu indicators in graphical form in a report called FluView. See the latest update by clicking here.

For an in-depth discussion about the national flu situation this week, click here.