“We had always been predicting this,’’ Dr. Lauren Smith, medical director of the state Department of Public Health, said yesterday. “We knew the H1N1 [swine flu] virus was going to be increasing. We didn’t know when, but now we do. It’s here.’’

It was just six months ago that the U.S. Centers for Disease Control and Prevention reported that two children in California had developed a respiratory illness never before seen in humans, referring to the infection as "swine flu" in its Morbidity and Mortality Weekly Report.

Flu activity is now widespread in 46 states. Nationwide, visits to doctors for influenza-like-illness are increasing steeply and are now higher than what is seen at the peak of many regular flu seasons. In addition, flu-related hospitalizations and deaths continue to go up nation-wide and are above what is expected for this time of year.

Below is a summary of the most recent key indicators:

• Visits to doctors for influenza-like illness (ILI) increased steeply since last week in the United States, and overall, are much higher than what is expected for this time of the year. ILI activity now is higher than what is seen during the peak of many regular flu seasons.
• Total influenza hospitalization rates for laboratory-confirmed flu are climbing and are higher than expected for this time of year.
• The proportion of deaths attributed to pneumonia and influenza (P&I) based on the 122 Cities Report has increased and has been higher than what is expected at this time of year for two weeks. In addition, 11 flu-related pediatric deaths were reported this week; 9 of these deaths were confirmed 2009 H1N1, and two were influenza A viruses, but were not subtyped. Since April 2009, CDC has received reports of 95 laboratory-confirmed pediatric 2009 H1N1 deaths and another 7 pediatric deaths that were laboratory confirmed as influenza, but where the flu virus subtype was not determined.
• Forty-six states are reporting widespread influenza activity at this time. They are: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming. This many reports of widespread activity are unprecedented during seasonal flu.
• Almost all of the influenza viruses identified so far are 2009 H1N1 influenza A viruses. These viruses remain similar to the virus chosen for the 2009 H1N1 vaccine, and remain susceptible to the antiviral drugs oseltamivir and zanamivir with rare exception.

Last week the CDC reported that influenza activity increased dramatically in the U.S.

• 4,855 (37.5%) 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 were positive for influenza.
• All subtyped influenza A viruses being reported to CDC were 2009 influenza A (H1N1) viruses.
• The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold.
• Eleven influenza-associated pediatric deaths were reported. Nine of these deaths were associated with 2009 influenza A (H1N1) virus infection and two were associated with an influenza A virus for which subtype is undetermined.
• The proportion of outpatient visits for influenza-like illness (ILI) was above the national baseline. All 10 regions reported ILI above region-specific baseline levels.
• Forty-six states reported geographically widespread influenza activity, Guam and three states reported regional influenza activity, one state, the District of Columbia, and Puerto Rico reported local influenza activity, and the U.S. Virgin Islands did not report.