Swine Flu Might Be Mutating, But We're Not Sure Because Virus Monitoring Sucks
The lack of reporting out of India's current outbreak puts the population at a greater risk, a new study shows.
Influenza virus. Image: Kat Masback/Flickr
A swine flu outbreak has killed more than 700 people in India since December. This is a strain of the H1N1 virus that killed hundreds of thousands of people worldwide in 2009, and a new study shows it may be mutating into an even deadlier version.
So if this deadly virus is back, why isn't there the same panic as when the disease first broke out in 2009?
Well, H1N1 isn't "back." It never went away, according to Lone Simonsen, co-director of the Global Health Epidemiology Program at George Washington University. When the swine flu pandemic happened in 2009, a lot of people got sick because it was a new strain of the H1N1 type virus. Nobody had any natural immunity to the virus, because nobody had been exposed to it before. After the first wave, the virus rolled into the normal rotation of flu viruses we see every flu season, Simonsen explained.
"We think of it now as another seasonal strain," Simonsen told me. "It happens all the time. We have epidemics of H1N1 in lots of countries, about every two years now. In Mexico, for example, they had a severe fourth wave of that virus in 2011-2012 season where suddenly they had a lot of hospitalization and death again. The same thing in England, they had a third wave two years after the pandemic where more people died than in the original one. The fact that H1N1 is circulating in India is not strange at all."
In India, there have been more 8,000 reported cases and between 700-800 reported deaths due to the outbreak since December. Simonsen suspects the number of actual cases is much higher and that lots of people who are getting sick are just staying home, riding it out like a normal flu, and not reporting it.
"Those numbers suggest that 1 in 10 people will die. That's unheard of, even for the Spanish influenza of 1918," she said. "It sounds like they're undercounting the cases, which can easily happen. It's not a criticism of Indian health care officials. Many people will not seek care when they get a fever."
And given the country's dense population—India has more than 1.2 billion people—it's likely thousands of more people are getting sick and recovering just fine, which makes the outbreak less severe overall.
"I mean it's tragic, but it's not that many deaths for such a big population. The United States, in an average flu season, might have 20,000 deaths and it's a smaller population," Simonsen said.
Outbreaks of any virus, even the more familiar H3 flu strain, need to be closely monitored, and that's not happening in India, according to a new study published today in Cell Host & Microbe journal.
Researchers at MIT analyzed the publicly available databases for records from this year's outbreak in India and found a major dearth of information. For example, they looked at a database of flu sequences which can be shared with the global health network. In the past two years, only two sequences have been submitted from India.
The problem is that, if the flu virus starts to mutate or change, it can turn into a new strain and quickly spread. If current outbreaks aren't being carefully monitored and documented, it puts the population at a great risk, the researchers wrote.
In analyzing the limited data available for this outbreak, MIT researchers Ram Sasisekharan and Kannan Tharakaraman found evidence that this strain may in fact be starting to mutate, despite reports from Indian health officials that it had not. They observed changes to the virus's amino acids that can make it both more deadly and spread more easily.
Unfortunately, the researchers concluded, without more data it's impossible to say how much, or if, the virus has really changed. We need to be doing more to facilitate a global network of virus monitoring, they say, to close the gap between discovering a new strain and developing a vaccine.
"There is an urgent need to develop a comprehensive and at least somewhat standardized response to influenza epidemic outbreaks," Sasisekharan and Tharakaraman wrote. "Improved surveillance and monitoring of the influenza outbreak will significantly enhance the options of how best we can manage outreach to both treat as well as prevent spread of the virus."