October 2, 2009

How many H1N1 cases have been reported at VUMC?

How many H1N1 cases have been reported at VUMC?

Seasonal influenza typically doesn't hit the nation until November, so the current glut of flu-like cases seen at Vanderbilt and elsewhere is attributed to the novel H1N1 influenza virus, which has lately been widespread in Tennessee.

Per guidelines published by the Centers for Disease Control and Prevention (CDC), patients who present with flu-like symptoms generally aren't being tested to confirm influenza; lab confirmation is ordered only for those patients who are exceptionally sick or otherwise immuno-compromised.

The number of flu-like cases being seen at Vanderbilt has subsided somewhat from highs seen earlier in September. But as of press time the numbers were still quite high – much higher than seasonal flu at its typical February peak.

“We view this now as a race between H1N1, seasonal flu, and vaccination against both for our patients, staff and doctors,” said Corey Slovis, M.D., chair of Emergency Medicine.

So far, H1N1 has sickened far more children than adults. On Sept. 6, the Pediatric Emergency Department saw more than 140 children with flu-like illness. By the week of Sept. 29, flu-like cases in the pediatric ED had dropped to 60 to 70 per day.

The usual daily expectation for September would have been around 18 to 24 flu-like cases in the pediatric ED, and perhaps another six or seven flu-like cases in the adult ED. The difference this year is H1N1.

“The Pediatric ED has responded really well, with doctors and nurses pitching in at the height to work extra shifts. It was pretty impressive to see the entire Department of Pediatrics respond to the onslaught,” said Paul Hain, M.D., associate chief of staff at the Monroe Carell Jr. Children's Hospital at Vanderbilt.

The week of Sept. 6 is also when daily flu cases peaked in the Adult Emergency Department and in Vanderbilt Medical Group adult and pediatric clinics.

At the height, the adult ED saw more than 20 patients per day with flu-like illness. More recently, flu-like cases in the adult ED have been in the range of 12 to 18 per day.

The single highest-volume day in Vanderbilt Medical Group clinics (i.e., excluding emergency departments) was Sept. 8, when 142 flu-like cases were seen across adult and pediatric clinics in Nashville and Williamson County.

Daily flu volume in the clinics is thought to have subsided some since early September, but data aren't yet available.