Dec 5, 2003 (CIDRAP News) – Signs of an unusually bad influenza season increased this week as federal health officials reported widespread influenza in 13 states and hints of a possible vaccine shortage began to appear.
In its weekly flu update, the Centers for Disease Control and Prevention (CDC) said today that flu activity was widespread last week in 13 states, most of them in the West. In Colorado, 6,306 confirmed cases had been reported as of Dec 3, more than twice the total for all of last season, according to the Colorado Department of Public Health and Environment.
Five Colorado children have died of flu this season, and a sixth death may have been flu-related, the department said. The children ranged in age from 21 months to 15 years. In normal flu seasons the state has an average of zero to two flu-related deaths in children, state health officials said in a news release.
A spokesman for vaccine maker Aventis SA predicted that the company might soon run out of flu vaccine, according to a Reuters report published today. The spokesman, Len Lavenda, said the current outbreaks around the country have spurred "unprecedented demand" for the vaccine. Signs of vaccine shortages were reported in several states this week, including Wyoming, Arizona, and New Mexico. In Arizona, a number of vaccination events around the state had to be canceled, according to the Associated Press.
In a statement today, the CDC said it is working with vaccine manufacturers, state health departments, and healthcare workers to assess the vaccine supply. "This year it appears that many more people than in recent years received a flu shot during October and November, and unlike other years, there is high interest in obtaining flu shots into December," said CDC Director Julie Gerberding.
She said the CDC is working to identify any localized surpluses of flu vaccine so that the extra doses can be made available where supplies are short. This year manufacturers produced 83 million doses of flu vaccine. In a typical year, 70 million to 75 million Americans receive flu shots, and the number has never exceeded 80 million, the CDC said.
The agency said it is not unusual for flu vaccine supplies to be limited at this time of year, when many healthcare providers begin to wind down their vaccination programs. "Therefore, people wishing to be vaccinated may need to be persistent to find vaccine," the CDC said.
This year there is also concern that the flu vaccine may offer less protection than usual. The CDC says the vaccine may not fully protect against a flu strain called Fujian A (A/Fujian/411/2002 [H3N2]), which has been prominent in virus isolates analyzed so far this season. The Fujian strain, which predominated in the Southern Hemisphere this year, is related to the vaccine strain, called A/Panama/2007/99 (H3N2). Of 157 influenza A viruses analyzed by the CDC so far this season, 29% were antigenically similar to the vaccine strain and 71% were similar to the Fujian strain.
The vaccine may be less effective against the Fujian strain than the Panama strain, but the vaccine is expected to offer "some cross-protective immunity" against the Fujian strain and to "reduce the severity of disease," the CDC states in its weekly flu report.
States with widespread flu activity last week included Alaska, Washington, Idaho, Nevada, Utah, Wyoming, Colorado, Nebraska, New Mexico, Texas, Arkansas, Tennessee, and Pennsylvania, according to the CDC. Regional flu outbreaks were reported in 16 states, local outbreaks in six states, and only scattered cases in 13 states.
The CDC said 5.1% of visits to representative healthcare providers last week were for influenza-like illnesses. The agency continued to advise people at high risk for flu complications and people who work with high-risk groups to get a flu shot.
Dr. Keiji Fukuda, a CDC medical epidemiologist who specializes in influenza, said it is too early to tell if high levels of flu will persist through the winter. "Flu is very unpredictable," he said in a news release. "It is not uncommon for seasons to be quite different in their timing. We still don't know how this season will progress."
CDC Dec 5 news release on flu vaccine supply