Single flu jab based on 1918 strain could provide protection for life

Scientists hail flu breakthrough that could confer lifetime immunity – ‘within five years’ – against future mutations after working on the influenza strain that killed millions after WWI.

Flu jabs currently have to be modified each year to fit the strain of the virus that is circulating. Picture: Getty Images

A single-shot vaccine against flu that would provide a lifetime of protection even against future mutations could be available in “five years or less”, scientists have said after making a breakthrough.

The researchers created a vaccine to target a 106-year-old strain of Spanish influenza that killed millions in 1918 and 1919 after WWI.

They found that the vaccine was also effective against a strain of bird flu from the 21st century, providing protection despite the virus having undergone almost a century of evolution.

Flu jabs have to be modified each year to fit the strain of the virus that is circulating in that particular season but scientists are hoping to develop a “one and done” vaccine that need be administered only once and can “confer lifetime immunity against an evolving virus”.

The new research, published in the journal Nature Communications, was conducted on macaques, who are our primate cousins and share about 93 per cent of their DNA with humans. Researchers at the Oregon Health and Science University (OHSU) said the study represented a leap towards a vaccine for use in humans.

“It’s exciting because in most cases, this kind of basic science research advances the science very gradually, [where you can say] ‘in 20 years, it might become something’,” said Dr Jonah Sacha, head of OHSU’s pathobiology department. “This could actually become a vaccine in five years or less.”

Eleven cynomolgus or crab-eating macaques were given inoculations against the deadly 1918 strain of Spanish flu. From 1918, the virus swept a world already devastated by the First World War and killed an estimated 50 million people, two to three times more than the death toll from the war itself.

The macaques were then exposed to one of the deadliest influenza viruses circulating in the world today, the H5N1 virus, better known as avian influenza or bird flu. A group of six unvaccinated macaques were all killed by the virus.

Out of the 11 animals vaccinated against the 1918 strain, six survived exposure to a strain of bird flu from 2004.

Sacha said the same approach used in their research could “absolutely” be applied to other mutating viruses, including Covid.

Instead of trying to trigger a response from the body’s antibodies, researchers developed their vaccine to trigger a response from the body’s T-cells. These attack the internal proteins of an invading virus, which do not tend to change much over time, rather than the spike proteins on the surface, which tend to mutate and change as the virus evolves between strains to evade the immune system.

The researchers took small segments of the flu virus and inserted them into a common herpes virus that infects most people in their lifetimes with mild or no symptoms. It was designed to trigger a response in a specific type of T-cell in the lungs called effector memory T-cells.

They had to work within a “highly secure biosafety laboratory” at the University of Pittsburgh to ensure that none of the Spanish flu or bird flu could escape into the general population.

“It worked because the interior protein of the virus was so well preserved,” Sacha said. “So much so, that even after almost 100 years of evolution, the virus can’t change those critically important parts of itself.”

He said that this meant that “a one-and-done shot for influenza is realistic”. He added said: “It’s a massive sea change within our lifetimes. There is no question we are on the cusp of the next generation of how we address infectious disease.”

The Times