A monoclonal antibody developed in the United States could provide new protection against H5N1 bird flu. Tests in non-human primates confirm its efficacy against more severe disease. The researchers are zeroing in on new targeted therapies, applying the knowledge gained during the Covid-19 pandemic.
There is growing alarm across Europe, after the United States, about the spread of H5N1 bird flu, which is affecting masses of farmed and wild birds, but also mammals. In recent months it has also begun to infect humans, albeit in small numbers and primarily people who were in close contact with infected animals, leading to death in some cases.
The monoclonal antibody MEDI8852: a possible solution to H5N1 bird flu
But hope is now on the horizon, with regard to the possibility of creating drugs capable of curbing the most severe situations. A new study published in the journal Science shows the potential of a broadly neutralising monoclonal antibody (bnAb) called MEDI8852.
This bnAb has proven very effective in tests on non-human primates. And while it can’t prevent infection (which is instead the job of vaccines), it does seem able to protect against the development of more dangerous bird flu. If necessary, this antibody can be tested and used on humans too, say the researchers.
How does the monoclonal antibody work against the H5N1 virus?
Researchers at the University of Pittsburgh and the US National Institutes of Health Vaccine Research Center used the same approach as the one explored during the Covid-19 pandemic to find more effective therapies when it had become clear that the coronavirus was mutating rapidly. The H5N1 virus also undergoes constant mutation, which is why the scientists decided to search its genetic code for more stable regions, which they then targeted with the antibody MEDI8852.
Monoclonal antibodies are similar to natural antibodies but are made in a laboratory using genetic engineering techniques to mimic the activity of the immune system and aim at a target chosen by researchers. Specifically, the US virologists directed the monoclonal antibody MEDI8852 at the stalk of the virus, which is at the bottom of a protein called haemagglutinin.
H5N1 bird flu: a treatment with up to 12 weeks’ protection
As reported in Science, laboratory animals (monkeys and others) were pre-treated with MEDI8852 and were exposed to bird flu three days later, by means of an aerosol developed in 2023 by the same research team.
None of the animals got severe symptoms or died from the infection. In addition, by trialling different doses, the scientists identified the minimum effective concentration to ensure adequate protection.
The duration of the protective effect is also interesting: the antibody MEDI8852 was found to be effective for 8 to 12 weeks, which is long enough to reduce the risk of falling ill in the event of an outbreak of the virus.
H5N1 bird flu – are we ready to deal with a new emergency?
Possible future use of MEDI8852 will probably not be available for everyone, however, as monoclonal antibodies are extremely expensive and need to be injected under medical supervision. What’s more, their production requires the use of bioreactors, of which there aren’t enough in the world to deal with a large-scale epidemic. But if the new drug is approved, it will be able to protect the most vulnerable, such as people with a weakened immune system or healthcare workers.
This study also shows that lessons have been learned from the Covid pandemic and that we could indeed be better prepared in the event of a new emergency. Virologists consider the H5N1 virus to be the most likely candidate for spillover – jumping from animals to humans and mutating until it becomes transmissible between humans. The scientific community is therefore already working on possible countermeasures: monoclonal antibodies to treat severe cases and vaccines to prevent them. Many laboratories around the world are hard at work developing preventive solutions to the H5N1 virus.
