Major trial for human bird flu vaccine launches

A first-of-its-kind trial has been launched to test a new vaccine for bird flu in humans.

Thousands of people in the UK are expected to be recruited for the study, with poultry farmers or those who have close contacts with birds encouraged to sign up.

The A(H5N1) strain of the virus is “evolving and spreading” in animals, and while it does not yet move easily between people, human-to-human transmission must be treated “as a real possibility”, experts said.

The mRNA-1018 vaccine, developed by Moderna, uses mRNA technology, similar to jabs for Covid-19.

It instructs the body to produce specific proteins from a specific virus to help train the immune system to recognise and respond quickly if it comes into contact with the illness.

The phase 3 trial will include around 4,000 people in the UK and US.

Some 3,000 UK patients – half of whom will be over 65 – will have the jabs at 26 sites across England and Scotland.

Poultry farmers or people who have close contact with birds are encouraged to sign up.

The A(H5N1) strain has come to affect birds globally in recent years, but has also caused outbreaks among other animals such as mink and marine mammals.

It had also spread to dairy cows in the US, with a number of human cases in those working on farms with affected cattle.

The study, backed by the National Institute for Health and Care Research (NIHR) and sponsored by Moderna, will take seven months, with patients given two doses of the vaccine three weeks apart.

According to Dr Hiwot Hiruy, senior director of clinical development at Moderna, said early trials of the jab found it to be “generally well tolerated, with most of the side-effects being mild to moderate, and there were no safety concerns”.

She added: “We also saw that mRNA-1018 induced a strong immune response, and that we were able to pick that immune response as early as seven days after the first injection, and the immune response persisted.”

Given the absence of bird flu in humans, researchers will use immune response as an early indicator that the treatment is likely to work.

Dr Rebecca Clark, who is based at Layton Medical Centre in Blackpool and is the trial’s national co-ordinating investigator, said: “We know that the A(H5N1) strain is evolving and spreading across animal species, and though it does not yet move easily between humans, we have to treat human-to-human transmission as a real possibility.

“This trial is our proactive attempt to shield against that possibility, and any future pandemic that could emerge from it.

“With recruitment sites across the country, we have shifted from traditional hospital settings into the heart of our communities, helping ensure the research can be carried out across a range of locations and populations.

“This work is an important part of strengthening our understanding of how we can respond to emerging public health threats and improve pandemic preparedness for the future.”

The A(H5N1) bird flu viruses first emerged in southern China in 1996, with the first human infections recorded a year later.

Since 2024, there have been 116 confirmed cases of bird flu in people across the world, with almost all linked to close contact with infected animals.

Dr Richard Pebody, director of epidemic and emerging infections at the UK Health Security Agency (UKHSA), said: “We clearly don’t know when the next pandemic is going to be, we obviously don’t know what it’s going to be caused by, but what we do know is that a flu pandemic is the most likely future pandemic.”

He added that while the current risk of bird flu in humans “remains low” the virus “continues to evolve”.

“UKHSA remains alert to the potential that this pathogen could adapt to spread from person to person, and will continue to monitor all available data,” Dr Pebody said.

“This important initiative to trial a new mRNA pandemic influenza vaccine is a key step towards further strengthening our ability to protect people against future influenza pandemics.”

At the end of 2024, the Government announced it had agreed a contract for more than five million doses of an H5 influenza vaccine to bolster pandemic preparedness.

The jab is based on a current H5 bird flu virus.

However, Dr Pebody said that the current stockpile uses more traditional vaccine technology.

Dr Hiruy also said that mRNA vaccines can be produced faster and can be adjusted to strains rapidly.

She said that while there are other vaccines out there, the new jab would be an “additional tool in pandemic preparedness”.