The U.S. Centers for Disease Control and Prevention restricted access on Thursday to samples of the 1918 pandemic flu virus taken from the frozen bodies and lung samples of victims, a standard precaution for such a dangerous virus.
Researchers who want to work with the virus, which killed anywhere between 20 million and 100 million people, depending on the estimate, will have to register with the CDC and account for their samples.
“We’ve learned why this virus was so deadly and we know it’s easily transmitted from person to person,” CDC Director Dr. Julie Gerberding said in a statement.
“But there is a lot we don’t know, so it’s only logical that we take immediate steps to regulate this virus as a select agent as an added way to protect the public.”
Select agents are considered potentially dangerous and are controlled.
The CDC lists 41 other organisms or toxins as select agents under the Public Health Security and Bioterrorism Preparedness and Response Act of 2002. They include Ebola virus, smallpox virus, the botulinum toxin and plague bacteria.
Understanding why so deadly
Earlier this month, researchers published a study in which they reconstructed the 1918 influenza virus, which was especially deadly and which swept the world at the end of World War One.
“The virus was reconstructed to aid public health officials in preparing for the possibility of another pandemic of influenza. It will also be helpful to biomedical scientists as they seek to understand what made the virus so harmful and to develop better antiviral drugs and influenza vaccines,” the CDC said in a statement.
Researchers wishing to study the 1918 virus can ask the CDC for samples. Gerberding said the CDC will send them to legitimate researchers who agree to the restrictions.
The researchers who reconstructed the 1918 flu virus studied mutations in the genes, to see why it became so deadly.
They compared it with the H5N1 avian influenza virus now sweeping through poultry in many Asian countries and into European countries including Russia and Romania.
Experts fear H5N1, which does not now easily infect people but which has killed more than 60, will mutate just enough to become a pandemic strain, passing easily among people and killing millions.
They found the 1918 flu virus appeared to also have passed directly from being a bird flu virus to being one that infected people, based on its genetic structure.