20/03/2023
Vaccine makers prep bird flu shot for humans 'just in case'; rich nations lock in supplies
Some of the world's leading makers of flu vaccines say they could make hundreds of millions of bird flu shots for humans within months if a new strain of avian influenza ever jumps across the species divide.
One current outbreak of avian flu known as H5N1 clade 2.3.4.4b has killed record numbers of birds and infected mammals. Human cases, however, remain very rare, and global health officials have said the risk of transmission between humans is still [USN:L1N35227C TEXT:"low"].
NEW APPROACHES
In a pandemic, vaccine manufacturers would shift production of seasonal flu vaccines and instead make shots tailored to the new outbreak when needed. They already have the capacity to make hundreds of millions of doses.
Many of the potential pandemic shots are pre- approved by regulators, based on data from human trials showing the vaccines are safe and prompt an immune response, a process already used with seasonal flu vaccines. This means they might not require further human trials, even if they have to be tweaked to better match whichever strain does jump to humans. Data on how well the vaccines actually protect against infection would be gathered in real-time.
In all, the WHO said there are close to 20 licensed vaccines against the broader H5 strain of flu. Existing antiviral treatments for people already infected will also help mitigate the impact.
At the same time, moving to large-scale production of a more targeted shot could take months, the manufacturers said. Some potential shots use a traditional method, growing the virus used in the vaccines in chicken eggs over four to six months
"Creating the first dose is the easiest," said Raja Rajaram, head of global medical strategy at CSL Seqirus. "The hardest is manufacturing in large quantities."
Experts have long advocated for new approaches in developing vaccines, both for seasonal and pandemic flu. COVID proved the potential of mRNA technology to adapt more quickly to changing viruses because the vaccines use genetic information from the pathogen, rather than having to grow the virus itself.
Moderna's mRNA vaccine research actually began with pandemic flu, and was modified for COVID, said Raffael Nachbagauer, executive director of infectious diseases at Moderna.
The company plans to launch a small human trial of an mRNA pandemic flu vaccine tailored to the new avian influenza subtype in the first half of 2023, he said, adding Moderna could respond "very quickly" in an outbreak scenario. The results will be closely watched, as the data on Moderna's seasonal flu candidate was [USN:L1N34W2C0 TEXT:"mixed"].
Nachbagauer said the company was mindful of the equity issue needing to be addressed but has
no contracts yet.
"It would be premature to sign anything or commit to anything that we can't actually deliver on as of today," he said.