The flu vaccine may only be 20 per cent effective this winter, researchers predict as the threat of a severe outbreak lies ahead.
A study found H3N2, the same strain which blighted Australia and caused an influx of cases during their winter, has mutated.
Scientists blame the 70-year-old manufacturing process of the vaccine, warning it has allowed the aggressive strain to escape detection.
Officials are concerned H3N2 will pose the same danger to Britain, as the flu season tends to mirror that of the Southern Hemisphere’s.
And experts are worried it could prove as deadly to humanity as the Hong Kong flu in 1968, which killed one million people.
The new findings, based on last year’s jab, echo the beliefs that this year’s vaccine isn’t strong enough to fight the aggressive strain.
The US Government-funded study backs up the belief that this annual year’s flu jab isn’t strong enough to fight an aggressive strain which has blighted Australia
University of Pennsylvania researchers found that last year’s jab, created by the World Health Organization, had between 20-30 per cent effectiveness.
The mutation did not show up in the mass-produced vaccine, said the report in the Proceedings of the National Academy of Sciences.
Flu vaccines work by delivering purified proteins from the outer layer of dead flu viruses, which primes the immune system to fight off a new invasion.
But if a virus mutates, and the vaccine doesn’t change to match it, effectiveness is lost, said lead author Dr Scott Hensley.
He said: ‘The 2017 vaccine that people are getting now has the same H3N2 strain as the 2016 vaccine.
‘So this could be another difficult year if this season is dominated by H3N2 viruses again.’
How is the vaccine made?
For more than 70 years, manufacturers have made the flu vaccine by injecting strains into chicken eggs.
This allows the virus to replicate. The fluid in the eggs is then purified to get enough of the virus to use in vaccines.
It strengthens the beliefs that this year’s flu jab isn’t strong enough to fight the H3N2 strain, which is expected to wreak havoc on the NHS this winter
But flu viruses are constantly changing proteins on their surface to avoid being spotted, and the old technique is helping them.
According to the study, a strain of the H3N2 virus with a different outer layer protein emerged during the 2014-2015 flu season.
Last year’s flu vaccine was updated to include the new version of this protein, but the egg-grown version had acquired a new mutation.
Researchers found antibodies elicited by the vaccine in ferrets and humans ‘did a poor job of neutralizing H3N2 viruses that circulated last year’.
But a version of the jab produced without eggs allowed antibodies to ‘recognize and neutralize the new H3N2 virus’.
Dr Hensley said that the new findings show that a new method urgently needs to be developed for widespread use.
THE EGG-BASED FLU VACCINE METHOD
Researchers at The Scripps Research Institute last month made similar findings about the egg-based method.
Dr Ian Wilson, study author, said viruses have to evolve to grow in the egg environment, meaning they mutate to develop better.
They found the egg-based process causes the virus to develop a mutation, called L194P, on one of its key proteins – hemagglutinin glycoprotein.
This mutation disrupts the region on the protein that is commonly recognized by our immune system, they wrote in PLoS Pathogens.
This means a vaccine containing the mutated version of the protein will not be able to trigger an effective immune response.
This leaves the body without protection against circulating strains of H3N2, which was behind one of Australia’s worst ever flu seasons.
He said: ‘Current H3N2 viruses do not grow well in chicken eggs, and it is impossible to grow these viruses in eggs without adaptive mutations.
‘Our data suggest that we should invest in new technologies that allow us to ramp up production of influenza vaccines that are not reliant on eggs.’
However, he urged people to go ahead and get the flu vaccine this year as ‘some protection is better than nothing’.
Australia – whose winter occurs during the British summer – had one of its worst outbreaks on record, with two and a half times the normal number of cases.
Some of the country’s A&E units had ‘standing room only’ after being swamped by more than 100,000 cases of the H3N2 strain.
Official figures are yet to confirm how many people have lost their lives to this year’s outbreak, but 370 deaths have been reported so far.
The elderly with their compromised immune systems are particularly susceptible, and a spike in cases among young children has also been shown.
The flu season in the UK and the rest of the Northern Hemisphere tends to mirror what has happened in Australia and the Southern Hemisphere.
The same strains of the virus will circulate north in time for the British flu season, which typically begins in November and lasts until March.
But there are concerns the vaccine, made by World Health Organisation scientists, will prove to be ineffective as it will not match the H3N2 strain
Scientists create the vaccines in March, based on which flu strains they expect to be in circulation. They are then given out in September.
Some health experts in Australia have blamed the severe outbreak on it having mutated. The vaccine used in the UK will be very similar.
Flu viruses are constantly changing proteins on their surface to avoid detection by the body’s immune system – making it more deadly.
This transformation is called an ‘antigenic shift’ if it’s large enough, and can lead to a pandemic. This was responsible for the swine flu outbreak in 2009.
The Aussie flu is transforming quickly, but not fast enough for experts to describe it as a shift. However, it is slowly building up immunity.
WHERE CAN YOU GET THE FLU JAB?
Flu can be a serious illness. If you become very ill with it, it can cause complications such as pneumonia, inflammation of the heart, brain or muscle, and kidney failure.
People at most risk of serious illness or death if they get flu are offered the vaccine on the NHS. Ideally you should have this before the end of December, when flu peaks (it takes about two weeks after the jab for antibodies to develop completely).
At-risk groups include anyone aged 65 and over; people living in long-stay residential care homes; carers and pregnant women.
The vaccine is also offered to anyone aged six months to 65 years with certain conditions, such as diabetes.
It is available via your GP’s surgery.
All children aged two to eleven (on August 31, 2017) are also offered the vaccine as a nasal spray. The UK introduced the child vaccination programme in 2013 — last year, the vaccine had 66 per cent effectiveness. Australia does not have a similar programme.
If you don’t qualify to have the jab on the NHS, you can pay to get it at a pharmacy.
Well Pharmacy charges £9 to £14 (depending on the number of strains in the vaccine), Superdrug from £9.99, Lloyds Pharmacy £10, Boots £12.99, and Tesco £9.
Older children who fall outside the NHS scheme can get the nasal spray vaccine from some pharmacies such as Well (£23 for those aged between two and 18; this may involve a second dose at least four weeks later for another £23) and the injection for those 12 and over for £9.
Boots offers the jab to those aged 16 and over at £12.99. Tesco offers it to those 12 and over at £9.