Researchers from Erasmus Medical Center have just published their research on the transmissibility of H5N1 avian influenza virus in the journal Science. The publication was delayed by several months due to the fact that various organizations first wanted to investigate whether the details could be misused by malicious individuals. In the study the researchers show that only a small number of mutations were necessary to change the H5N1 virus so that it can spread through the respiratory system between mammals. This implies that the risk of a H5N1 pandemic cannot be ruled out.
"We show that only five to 10 mutations are necessary before H5N1 becomes transmissible by air," says research leader and virologist Ron Fouchier of Erasmus Medical Center. The researchers found changes in the virus that were as yet unknown, giving them a better understanding of how viruses become transmissible by air. The knowledge gained on these changes can be used by researchers to determine worldwide whether the virus does actually undergo these changes and becomes a threat to humans and/or animals. A second publication in the same edition of Science discusses this in further detail. Furthermore, timely testing of drugs and vaccines can take place.
Initially, the researchers determined how viruses that had caused a pandemic in the past had developed. Fouchier notes, "What genetic changes were apparent in these viruses from 1918, 1957 and 1968? Using this knowledge we manipulated the avian influenza virus in such a way that it became transmissible by air. They succeeded in doing this after repeatedly passing the virus in the ferrets nose. Eventually the ferrets started sneezing and coughing thereby infecting other ferrets."
The researchers studied various viruses to determine which mutations in the genes are specifically responsible for the virus becoming airborne.
The publication in Science has been a long time in coming. Various organizations were concerned that in addition to the benefits the research could also be misused, for example, by bioterrorists. The World Health Organization (WHO), the National Science Advisory Board for Biosecurity (NSABB) and the Dutch government first wanted to obtain clarity on these risks. The researchers have proven that it is safe to publish the study and that the research was conducted under safe conditions. They showed that the virus is not deadly when transmitted by air.
The article has not been censored, stresses Fouchier. "All methods and results are the same as in the original manuscript and no data has been removed." On consultation with the organizations, the researchers actually added information as it is likely that this manuscript will be read by a broader audience than is usually the case for this type of publication. "Among other, we explain in detail why this research was carried out, the benefits to public health and how we ensure that the research is conducted as safely as possible."
The research on H5N1 came to a standstill at the end of January. The researchers decided to take a break to allow for the public debate that had ensued. They want to proceed with the experiments once the general public has been given sufficient information and all authorities are convinced that the research can be continued safely. Says Fouchier, "In publishing our work we will finally be given the opportunity to discuss if and when we can continue our research. There are many questions remaining to be answered and we want to find these answers."