Dec 24, 2008 (CIDRAP News) – While the US influenza season has started slowly, cases are surging in England, raising concern that the country could have its toughest season since 1999-2000.
In England and Wales last week, about 68.5 people per 100,000 saw a general practitioner for influenza-like illness (ILI), a 73% increase over the 39.5 per 100,000 the week before, according to the latest weekly report from the Royal College of General Practitioners (RCGP). A BBC News report said the number also is73% higher than the same week a year ago.
Dr. Douglas Fleming, director of the RCGP Research Unit in Birmingham, said the increase was significant, according to BBC News. "In the past 10 years, the only substantial outbreak was in 1999-2000," he said. "I think we could be looking at something that approaches that this year."
The RCGP report says ILI visit rates of 30 to 100 per 100,000 population per week are "usual when influenza viruses are circulating," rates above 100 are above average, and rates exceeding 200 are "exceptional." The RCGP data are drawn from about 85 general practitioner clinics around the country, representing an at-risk population of about 840,000.
ILI rates rose in all age-groups and regions in the week of Dec 15 to 21, the RCGP report says. The highest rates were seen among 15- to 44-year-olds, with 79.7 cases per 100,000, and 45- to 64-year-olds, with 75.6 cases. The 65-and-older group had 44.7 cases per 100,000, which was more than double the 18 cases seen the week before.
The BBC report said experts believe the unusually cold weather might have contributed to the surge in cases.
British public health officials define a flu epidemic as an ILI rate of 200 per 100,000, according to the BBC story. The last time that happened in England was in 1989-90, the report said.
"That one caught everyone a bit off guard but there's been a big push on flu vaccination since then," virologist John Oxford of Queen Mary's School of Medicine and Dentistry in London told the BBC.
Oxford and others quoted in the story urged people to get a flu shot if they haven't done so yet.
David Salisbury, director of immunization at the UK Department of Health, told the BBC, "We have had a very unusual run of winters with almost no flu, so we should not be surprised that here is a winter with more flu. It is very difficult to predict what makes the change winter to winter."
In contrast to the situation in England, flu activity in the United States has remained low so far this season, according to the latest report from the Centers for Disease Control and Prevention, issued Dec 19. The report, for the week that ended Dec 13, said only three states—Texas, Virginia, and Hawaii—were reporting local flu activity. Thirty-six states reported sporadic cases and 11 states were reporting none.
Google Flu Trends, a Web site that estimates US flu activity from the volume of Internet searches for flu information, currently shows "moderate" activity only in Hawaii, Maryland, and Virginia, with the rest of the country having low activity.
See also:
CDC flu surveillance update
http://www.cdc.gov/flu/weekly/
Google Flu Trends
http://www.google.org/flutrends/
