May 28, 2013
The ongoing spread of H7N9 avian flu across Asia could be much more serious than the mainstream media is currently leading on, as some reports now suggest that the actual number of infections and deaths may be at least double what is being reported. Researchers from the University of Hong Kong (UHK) say there could already be as many as 120 adults with H7N9 that are flying under the radar due to milder infections that have not yet been detected.
As of last month, the World Health Organization (WHO) is reporting 109 confirmed cases of H7N9 infection and 22 deaths from the disease. The majority of infections have thus far emerged in Zhejiang, Shanghai, and Jiangsu, but the first confirmed case of H7N9 outside of China was recently identified in nearby Taiwan. And according to reports, the condition is striking primarily elderly males, with younger populations less susceptible to infection.
But if you add another 120 mild cases of H7N9 to the mix, the overall number of infected individuals more than doubles to 229 cases. According to Benjamin Cowling, an associate professor at UHK’s Public Health Research Center, this figure is likely more accurate than the official one, and there could even potentially be many more infections that have yet to emerge and be reported.
“One thing that is very striking is the age distribution of the cases,” says Cowling, as quoted by Bloomberg.com. “They’re very different from the confirmed infections of H5N1,” he adds, noting that H5N1 has mostly afflicted younger people in their 20s and 30s.
You can monitor the spread of H7N9 using Bloomberg‘s graphic tracking module:
People vaccinated with seasonal, H1N1 flu vaccines more susceptible to serious H7N9 infection
With a current mortality rate of about 20 percent, H7N9 appears to be a particularly virulent flu that many health experts are concerned may lead to a pandemic. The infamous 1918 Spanish Flu, according to The New Yorker, is estimated to have killed as many as 100 million people worldwide in three deadly waves, and it only had a roughly two-percent mortality rate.
“It could be that hundreds of other people have mild infections” with H7N9, says Tom Frieden, Director of the U.S. Centers for Disease Control and Prevention (CDC), confirmed the UHK researchers’ assessment of the situation.
But what is even more disturbing is the fact that people who have already been vaccinated for seasonal flu or H1N1 swine flu may be more susceptible to serious infection or death from H7N9, should they contract it, compared to those who have not been vaccinated. A paper recently published in the journal Eurosurveillance explains that flu vaccines can prevent neutralizing antibodies from recognizing new pathogens, resulting in weakened immunity and higher susceptibility to more serious infection.
“Sometimes - and for reasons that aren’t well understood – an earlier viral infection can set the host up for a more serious infection when exposed at a later date to a similar virus,” explains the paper. “The problem usually comes later, when a person is infected with a different serotype,” it adds, referring to closely-related, yet distinct, viruses that can cause more serious infection down the road.
What this means, of course, is that all those people who rushed to their local flu clinics to get jabbed for H1N1 swine flu back in 2008 and following could be the ones most seriously affected by H7N9, should it spread globally.
You can read the full Eurosurveillance paper here:
You can also read an assessment of it compiled by the blog Avian Flu Diary here:
Sources for this article include:
This article was posted: Tuesday, May 28, 2013 at 10:25 am