Vaccine makers like Moderna say they are “ready” for a human bird flu pandemic

Big vaccine companies are preparing bird flu vaccines in case the H5N1 virus, which has killed millions of animals, mutates to infect humans.

Vaccine makers GSK, Moderna and CSL Seqirus have begun developing new human vaccines to combat the fast-spreading strain of the virus. Others, like Sanofi, have stockpiled vaccines against the H5N1 virus that could serve as the basis for making syringes tailored for the strain currently circulating.

Epidemiologists claim the risk to humans is low, but the specter of another pandemic claiming hundreds of millions of lives worldwide has sent the scientific inquiry into overdrive.

The strain currently ripping through bird populations — H5N1 clade 2.3.4.4b — didn’t evolve to infect humans, but it has begun to spread at an unprecedented rate in mammals after causing record deaths in birds — which is the Increased chance of stain acquiring dangerous mutations.

An 11-year-old Cambodian girl recently made headlines for becoming the first person to die of bird flu this year.

But Cambodian scientists who have sequenced the virus’ genome have confirmed that the clade that killed it – 2.3.2.1c – is not the one causing mass deaths in wild and domestic birds worldwide.

Still, the virus’ proven ability to rapidly mutate and jump from birds to mammals worries experts. There have been fewer than 1,000 human cases, but it has killed about 53 percent of people diagnosed with the disease.

The Director-General of the World Health Organization, Tedros Ghebreyesus, warned last month: “Since H5N1 first emerged in 1996, we have seen only rare and non-sustained transmission of H5N1 to and between humans, but we cannot expect it to continue will, and we must prepare for any change in the status quo.’

The current avian flu outbreak has infected or killed more than 200 million birds and thousands of mammals worldwide, including mink in Spain, seals in the US, sea lions in South America and dolphins in the UK.

Executives from GSK, Moderna and CSL Seqirus told Reuters they will develop or test samples of human vaccines that better match the circulating subtype. Sanofi, meanwhile, said they are ready to start production if needed, with existing H5N1 vaccine strains in stock.

The US also keeps a stock of chickens to produce eggs, which are crucial for developing flu vaccines, a method that has been used for about 80 years.

Hundreds of thousands of eggs are placed every day in locked and guarded facilities whose whereabouts are not disclosed for reasons of national security.

To make the vaccine, a selected virus is injected into chicken eggs, where it incubates and replicates for a few days in much the same way as a human.

Scientists extract fluid from the egg that contains the virus and inactivate it so it can no longer cause disease, cleaning it and leaving behind the crucial antigen that triggers an immune response if infected.

Moderna, maker of one of two pioneering mRNA vaccines for Covid, meanwhile, is working on a pandemic flu vaccine tailored for avian flu using the same technology.

The basis for Moderna’s successful use of mRNA technology for Covid-19 was seasonal flu shots.

While vaccine development would normally take years or even a decade, the Covid pandemic has accelerated the process, producing two highly effective mRNA vaccines in less than 12 months.

Raffael Nachbagauer, Moderna’s executive director for infectious diseases, told Politico that the company will begin clinical trials of an mRNA vaccine for pandemic avian influenza this year.

If they do, he hopes they will be able to respond “within two months to a true pandemic outbreak” with a shot equipped to combat the specific circulating strain.

But there are concerns that while many types of influenza vaccines have been pre-approved by regulators to reduce the risk of lengthy human clinical trials slowing the crucial distribution of vaccines, mass-produced versions have been tweaked depending on the specification load can take months.

Raja Rajaram, head of global medical strategy at CSL Seqirus, said, “Manufacturing the first dose is the easiest… The most difficult thing is manufacturing in bulk.”