|"It's like the avian flu on steroids"|
|By Staff and Wire Reports|
|Saturday, 17 October 2009 15:42|
The Centers for Disease Control and Prevention reported Friday that H1N1 vaccine production was proceeding more slowly than hoped. Officials had predicted that about 40 million doses would be available by the end of October, but that projection will probably fall short by about 10 million to 12 million doses, this according to a front page story in this weekend's Washington Post.
Seasonal flu viruses tend to infect primarily the upper respiratory system. But recent animal studies and autopsies on about 100 swine flu victims show that H1N1 infects both the upper respiratory tract, which makes it relatively easy to transmit, and also the lungs, which is more similar to the avian flu virus that has been circulating in Asia.
"It's like the avian flu on steroids," said Sherif Zaki, chief of Infectious Disease Pathology at the CDC. He noted that unusually large concentrations of the swine flu virus have been found in the lungs of victims: "It really is a new beast, so to speak."
About a third of patients who required intensive care had bacterial pneumonia, but H1N1's proclivity to infect lung cells makes it more likely than seasonal flu to cause viral pneumonia, which can lead to life-threatening lung damage.
"Remarkably different is this small subset of patients that presents very severe viral pneumonia," Shindo said.
One of those patients was Karen Ann Hays of Sacramento, Calif., an otherwise healthy nurse whose hobby was tackling grueling triathlons. Despite desperate measures to keep her alive, Hays, 51, died in July within days of coming down with swine flu.
"I have seen more cases like this in the last three months than I have in the last 30 years," said Peter Murphy, director of intensive care at the Mercy San Juan Medical Center in Carmichael, Calif., who tried to save Hays.
Although it remains unclear how frequently the virus makes people seriously ill, recent reports from Mexico, Canada, the United States, Australia and New Zealand indicate that perhaps 1 percent of patients who get infected require hospitalization. Between 12 to 30 percent of those hospitalized need intensive care, and 15 to 40 percent of those in intensive care die.
While about two-thirds of U.S. patients who were hospitalized in the spring had other medical conditions, the CDC reported this week that an analysis of more than 1,400 hospitalized victims found perhaps half had no serious health problems.
About one-third of those around the world who have died or became seriously ill from swine flu appear to have been vulnerable because they had heart or lung disease, chronic kidney problems, or other ailments that usually put people at risk. But others had conditions that many may not immediately associate with frailness, such as mild asthma, high blood pressure, high cholesterol and obesity.
"Many of these people look just like you or me," said Anand Kumar, an associate professor of critical care and infectious disease at the University of Manitoba in Winnipeg, Canada, which was hit hard by the pandemic's first wave last spring.
Elsewhere, the Los Angeles Times is reporting that swine flu activity is widespread in 41 states, up from 37 last week, and all the other states are reporting regional or local activity, Schuchat said. That level of activity "is unprecedented for this time of year." On average nationally, 6.1% of visits to doctors' offices are for influenza-like illness, which is generally assumed to be swine flu.