My weekend has finally begun and I’m caught up enough from attending the IDSA Seasonal and Pandemic Influenza conference Monday and Tuesday, now I get to sit down to comment on a few things that caught my attention this week on the PanFlu – H5N1 front.
The first is a Reuters article by Maggie Fox, a reporter/editor with well established credentials as a health and science writer/editor, often lacking in the world of All Things News and Reporting. I make the statement of Ms. Fox’s well-established credentials for two reasons: A) I respect her body of work, and B) Ms. Fox is not a reporter given a random assignment on a topic she has no familiarity.
By Maggie Fox, Health and Science Editor, Thu Feb 5, 2009
WASHINGTON (Reuters) – Strep infections and not the flu virus itself may have killed most people during the 1918 influenza pandemic, which suggests some of the most dire predictions about a new pandemic may be exaggerated, U.S. researchers said on Thursday.
The findings suggest that amassing antibiotics to fight bacterial infections may be at least as important as stockpiling antiviral drugs to battle flu, they said.
Keith Klugman of Emory University in Atlanta and colleagues looked at what information is available about the 1918 flu pandemic, which killed anywhere between 50 million and 100 million people globally in the space of about 18 months.
Some research has shown that on average it took a week to 11 days for people to die — which fits in more with the known pattern of a bacterial infection than a viral infection, Klugman’s group wrote in a letter to the journal Emerging Infectious Diseases.
“We observed a similar 10-day median time to death among soldiers dying of influenza in 1918,” they wrote. [emphasis added]
The graph included in the Emerging Infectious Diseases letter, but not included in the news article:
Image may be NSFW.
Clik here to view.
The graph shows that by day 11 ~47% from 1918 and ~50% from 1920s &30s had a fatal outcome. Furthermore, 10 is the median day of a 20-day spread, it would matter not what percentage was dead at that day… it is the median day.
What about the approximately 40% of the fatal outcomes prior to day six? The graph is not especially user-friendly, or perhaps, it’s just not very “layman-friendly”. I’m not a scientist, but to my layman’s eyes there is something terribly “forced” in how the findings are worded.
People with influenza often get what is known as a “superinfection” with a bacterial agent. In 1918 it appears to have been Streptococcus pneumoniae.
“Neither antimicrobial drugs nor serum therapy was available for treatment in 1918,” Klugman’s team wrote.
Now there are also vaccines that protect against many different strains of S. pneumoniae, which cause infections from pneumonia to meningitis.
Again, the wording is not especially “informative of the facts”. A “superinfection” is an infection of an additional pathogen, or pathogens, while a person is still struggling with the original viral or bacteriological infection.
It has been reported that influenza can – and does on occasion – “set up” the human body to be overrun by common upper respiratory tract bacteria, two of which are Streptococcus and Staphylococcus, both common causes of bacterial pneumonia.
WORST-CASE SCENARIO
Most health experts agree that another pandemic of influenza is inevitable. There were smaller pandemics in 1958 and in 1967.
Many government projections have been based on a worst-case 1918 scenario, in which tens of millions of people would die globally and up to 40 percent of the work force would be out for weeks, either sick, caring for others who are sick, or avoiding public places for fear of infection.
“Based on 1918 we would project less mortality in an era of antibiotics,” Klugman said in an e-mail.
“We -are currently modeling this — assuming of course that the bacterial superinfections remain susceptible to the antibiotics and that sufficient antibiotics are available.”
No one knows when a pandemic of flu might strike. Every year seasonal influenza kills between 250,000 and 500,000 people.
A pandemic occurs when a new strain of flu begins infecting people. One big fear is that H5N1 influenza, currently infecting many birds in Asia, Europe and Africa, might make the jump to people.
H5N1 currently infects people only rarely but it has killed 254 out of 405 infected since 2003, according to the World Health Organization. Many countries and companies are stockpiling antiviral drugs and vaccines in case it does strike.
Be that as it may, as was reiterated at the IDSA Seasonal and Pandemic Influenza conference just this past Monday and Tuesday, (and at last year’s as well) there is no evidence (yet) that bacterial pneumonia is a factor in the human H5N1 deaths thus far.
I make that statement knowing that we do not have many autopsies of human H5N1 fatalities to say that there have been no deaths from bacterial pneumonia, just that we do not know of any because autopsies have not been performed on the majority of fatalities.
A snip from a paper published in the October 1, 2008 Journal of Infectious Diseases by David M. Morens, Jeffery K. Taubenberger, and Anthony S. Fauci:
Predominant Role of Bacterial Pneumonia as a Cause of Death in Pandemic Influenza: Implications for Pandemic Influenza Preparedness [link]
[snip]
The viral etiology of and timing of the next influenza pandemic cannot be predicted. If, as some fear, a future pandemic is caused by a derivative of the current highly pathogenic avian H5N1 virus, lessons from previous pandemics may not be strictly applicable. Although histopathologic information concerning current human H5N1 infections is sparse, its pathogenic mechanisms may be atypical because the virus is poorly adapted to humans and because, in certain experimental animal models, some strains have induced severe pathology that differs from the findings associated with circulating human influenza viruses (which, in these models, cause disease resembling self?limited seasonal influenza in humans). However, if an H5N1 virus were to fully adapt to humans, the clinicopathologic spectrum of associated disease could become more like that of previous pandemics. [all emphasis added]
Different strains of influenza virus have different disease profiles. An H1N1 infection is generally milder than one from H3N2. H1N1 of today produces a far milder infection now than it did when it first burst upon the human population. It may be folly of a high order to assume the next strain of pandemic influenza will behave like any of the others, and not something unique. A point underlined in the above snip. Something that is being lost in the “noise” of this news, just as it was lost the first time this news was trotted out back in October of 2008 when the Morens, Taubenberger, and Fauci paper was first published.
I certainly agree that antibiotics should be stockpiled, bacterial pneumonia can be a major player, fatally or not, when influenza is involved, however, prudence dictates that we not be lulled into a false sense of security by words served up to us that are less than fully informative.
SZ