‘Universal’ flu vaccine promises long-lasting immunity
In a paper published in Nature Communications on Wednesday, researchers at Georgia State University say they have created a “universal vaccine” that provides long-lasting immunity against several variations of the influenza virus.
Since the flu can be caused by hundreds of different types of virus, scientists at the World Health Organization spend five to six months identifying which influenza viruses will be the most common in the upcoming season to develop a flu vaccine each year.
Traditional flu vaccines target the “head” of the virus’ surface protein, known as hemagglutinin (HA). The protein is what helps the virus cling to the cells in the nose, throat and lungs of an infected person, where it grows and spreads.
Seasonal vaccines contain inactivated virus particles made with the heads of those proteins in order to train the body’s immune system to produce antibodies against the virus. However, the protein heads are different for each virus, and they are typically the first parts of the virus to mutate. The US Centers for Disease Control and Prevention (CDC) states that the flu vaccine works better against some influenza strains than others, and only typically reduces the risk of flu illness by between 40 and 60 percent.
“The seasonal influenza vaccines induce the dominant immune response against the head domain of the HA molecules, which is hypervariant,” Dr Lei Deng, co-author of the study, said in a statement. “That is why we have to adopt new influenza strains for the new vaccine every year. Our vaccine overcomes this problem.”
To provide wider protection, the researchers said they used double-layered protein nanoparticles to target the body, or “stalk,” of the virus instead of the head.
“What we wanted to do is to induce responses to this stalk part of the influenza surface glycoprotein, not the head part. This way you’re protected against different viruses because all influenza viruses share this stalk domain,” Dr Bao-Zhong Wang, co-author of the study, said in a statement.
Wang said the stalk is the most effective part of the virus to target since it does not mutate as fast or drastically, which means scientists would not need to develop and administer a seasonal vaccine each year.
“You wouldn’t need to change the vaccine type every year because it’s universal and can protect against any influenza virus,” Wang said.
To test the effectiveness of the protein, researchers immunized mice that were then exposed to several influenza viruses, including H1N1, H3N2, H5N1 and H7N9. The study claims that the immunization provided “universal, complete protection against lethal virus exposure and dramatically reduced the amount of virus in the lungs.”
Researchers will test the vaccine on ferrets next, which have a similar respiratory system to humans.
According to the most recent weekly report from the CDC, 30 children have died of the flu in the US since October. While the CDC does not record how many adults have died from the virus, the Los Angeles Times reported that 74 people under the age of 65 have died of the flu since October, compared to 14 in the same period last year.
“California is facing the same problem that most of the US is facing,” said Dr Karen Smith, Director of the California Department of Public Health, according to the Los Angeles Times. “This has been a very early season and a more severe one.”
For the first time in 13 years since the CDC began tracking influenza, “widespread” influenza activity was reported across 49 states, with “high activity” in 32 states.
The CDC estimates that anywhere from 3,000 to 49,000 people die from flu-related complications each year. However, a recent outbreak of the H1N1 virus in 2009 caused an estimated 151,700 to 575,400 deaths during the first 12 months the virus circulated.