CDC

During week 10 (March 2 – 8, 2008), influenza activity continued to decrease in the United States.

One thousand nine hundred thirty-six (21.6%) specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories were positive for influenza.

The proportion of deaths attributed to pneumonia and influenza was above the epidemic threshold for the ninth consecutive week.

The proportion of outpatient visits for influenza-like illness (ILI) was above national baseline levels, while the proportion of outpatient visits for acute respiratory illness (ARI) was below national baseline levels. ILI decreased in eight of the nine regions compared to week 9, and fell below the region specific baseline in the Mid-Atlantic region, but remained above region-specific baselines in the remaining eight regions. The West North Central region reported ARI above its region-specific baseline.

Forty-two states reported widespread influenza activity; eight states reported regional influenza activity; the District of Columbia reported local influenza activity; and Puerto Rico reported sporadic influenza activity.

During week 10, 8.7% of all deaths reported through the 122 Cities Mortality Reporting System were reported as due to P&I. This percentage is above the epidemic threshold of 7.2% for week 10. Including week 10, P&I mortality has been above epidemic threshold for nine consecutive weeks.

Eight influenza-associated pediatric deaths were reported to CDC during week 10 [ME, MA, NJ, NM, PA(2), VA, and WI]. These deaths occurred between February 15 and March 2, 2008. One additional death from Illinois, confirmed during week 9, was not reported last week. Since September 30, 2007, CDC has received a total of 41 reports of influenza-associated pediatric deaths that occurred during the current season.

As ususal, posting data well behind the actual date. This is through March 1.

CDC

• Two thousand four hundred one (27.2%) specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories were positive for influenza.
• The proportion of deaths attributed to pneumonia and influenza was above the epidemic threshold for the eighth consecutive week.
• The proportion of outpatient visits for influenza-like illness (ILI) and acute respiratory illness (ARI) was above national baseline levels. ILI decreased in seven of the nine regions compared to week 8, but remained above region-specific baselines in all nine regions. The Mid-Atlantic and West North Central regions reported ARI at or above their region specific baselines.
• Forty-seven states reported widespread influenza activity; three states reported regional influenza activity; and the District of Columbia reported local influenza activity.

Neuraminidase Inhibitor Antiviral Drugs: Of the 743 influenza A and B viruses from the United States tested for antiviral resistance so far this season, 45 (6.1%) have been found to be resistant to oseltamivir. Currently all of the resistant viruses are H1N1 viruses, with 45 (8.7%) of 519 H1N1 viruses tested exhibiting a genetic mutation that confers oseltamivir resistance. All tested viruses retain their sensitivity to zanamivir.

Adamantane Antiviral Drugs: Resistance to the adamantanes continues to be high. Among 511 influenza A viruses tested, 111 (21.7%) are resistant to adamantanes, including 98.9% of H3N2 viruses and 4.3% of H1N1 viruses. The adamantanes are not effective against influenza B viruses.

Based on the level of oseltamivir resistance observed in only one influenza subtype, H1N1, and persisting high levels of resistance to the adamantanes in both H3N2 and H1N1 viruses, CDC continues to recommend the use of oseltamivir and zanamivir for the treatment or prevention of influenza. Use of amantadine or rimantadine is not recommended.

CDC

During week 8 (February 17 – 23, 2008), influenza activity decreased slightly in the United States.

Two thousand three hundred twenty-one (30.0%) specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories were positive for influenza.

The proportion of deaths attributed to pneumonia and influenza was above the epidemic threshold for the seventh consecutive week.

The proportion of outpatient visits for influenza-like illness (ILI) and acute respiratory illness (ARI) was above national baseline levels. ILI decreased in seven of the nine regions compared to week 7, and was above region-specific baselines in all nine regions. The East South Central, Mid-Atlantic, Mountain, New England, Pacific, South Atlantic and West North Central regions reported ARI at or above their region specific baselines.

Forty-nine states reported widespread influenza activity; one state reported regional influenza activity; and the District of Columbia reported local influenza activity.