Bird flu viruses would have to make at least two simultaneous genetic mutations before they could be transmitted readily from human to human, according to research published in PLoS ONE.
The authors of the new study, from Imperial College London, the University of Reading and the University of North Carolina, US, argue that it is very unlikely that two genetic mutations would occur at the same time. The study adds to current understanding of why avian influenza has not yet caused a pandemic. Earlier this year, the Imperial researchers also showed that avian influenza viruses do not thrive in humans because, at 32°C, the temperature inside a person’s nose is too low. H5N1 has a high mortality rate in humans, at around 60%, but to date there has been no sustained human to human transmission of the virus, which would need to happen in order for a pandemic to occur. Professor Wendy Barclay, corresponding author of the study at Imperial College London, said: “Our new research suggests that it is less likely than we thought that H5N1 will cause a pandemic, because it’s far harder for it to infect the right cells. The odds of it undergoing the kind of double mutation that would be needed are extremely low. However, viruses mutate all the time, so we shouldn’t be complacent. Our new findings do not mean that this kind of pandemic could never happen. It’s important that scientists keep working on vaccines so that people can be protected if such an event occurs.”
