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Thursday March 29, 2018

The Search for a One-Time Flu Vaccine

Christmas

Doctors and public health experts were bracing for a particularly severe flu season, and it unfortunately, and in many cases tragically, came true. It was a difficult winter of flu, and  though disease activity has been down in the past couple of weeks, the CDC has been warning that a second wave, this time of the B strain of flu, appears to be making the rounds.

Making matters worse, this year’s flu vaccine was not as effective as it is many years, though it was far more effective than many had thought.

But wouldn’t it be wonderful if there were a single, effective flu shot that worked for all strains? One that we might get once and never need again?

Scientists are at work on that right now, and they think they might have found a pathway to making it work. Their work revolves around overcoming two issues: While a few flu strains predominate each year, there are many more around. That means that each year, vaccine makers and public health officials must make an educated guess about which strains should be included in that year’s vaccine – and they have to do it many months before flu season arrives, because incubating the vaccine in eggs takes a long time.

Then there’s the problem of the flu virus’s sneakiest trick – its propensity to mutate often and quickly, unlike the measles virus, which remains stable.

One branch of research has looked into ways to produce the vaccine far more quickly, in order to match whatever strains dominate during flu season.

But other researchers are working on circumventing the entire problem by creating a vaccine that will work for any flu.

It all has to do with which part of the virus the vaccine tackles.

In this case, researchers are focusing on the hemagglutinin protein, which covers the outside of the flu virus. Think of the protein as being shaped like broccoli – a stalk with a wider head. As a press release from the University of Rochester Medical Center explains it, our current vaccines target the head of the broccoli, which is the part that’s always changing.

But scientists believe that the stalk is much less inclined to change, and that this is the part of the virus they’ll need to target.

Of course, it’s not quite that simple. The head is the part of the flu virus that the human body reacts to the most, and produces antibodies to fight, according to a report in Science News. But in 2011, researchers published a study  in the Journal of Experimental Medicine showing that if antibodies encountered a totally unfamiliar virus “head,” they were more likely to attack the stalk.

And a year later, a study published in Frontiers in Immunology reported that if those stem-attacking antibodies were injected into mice, the mice were protected from a totally different strain of the virus.

According to the article in Science News, the obstacle that needs to be overcome is keeping those familiar “heads” out of the picture, so that the immune system will go after the stalk instead. This might mean creating headless stalks, which is a lot more challenging than it sounds because, unlike with our metaphorical broccoli, the stem falls apart without the head. Scientists are looking at various ways to do that, including genetic modification. Another group took the head of a virus that affects only birds – so it would be unfamiliar to other species – and attached it to the stalk of another virus.

But scientists at the University of Rochester’s New York Influenza Center of Excellence said that although stalk research could result in a much improved vaccine that covers more strains and works far longer, it’s unclear that such a vaccine would last a lifetime. Their research shows that repeated exposure to assaults from the body’s immune system can trigger mutations in the stalk as well.

“The good news is that it’s much more difficult to drive mutations in the stalk, but it’s not impossible,” said David J. Topham, co-director of the Center for Excellence.

Other scientists are taking a totally different approach, Science News reported. It described the work of researchers at the University of Georgia who took hemagglutinin mutations from every H1N1 flu strain that had circulated, and attached the blend to a particle to make a vaccine that was found to protect mice from a flu they had never encountered before.

The researchers are now working on doing the same thing with the H3N2 flu virus, which is the one that sickened so many people in Australia last winter and appears to be responsible for the more serious cases of flu in the United States now.

The National Institute of Allergy and Infectious Diseases is working along similar lines.

“Instead of trying to predict which influenza virus strains are likely to cause human disease and then make a vaccine to match those specific strains,” NIAID  reported, “Jeffery Taubenberger, M.D., Ph.D., and his colleagues created a vaccine cocktail incorporating four of the 16 different subtypes of an influenza virus protein called hemagglutinin.”

The scientists then vaccinated mice with the cocktail, and “exposed them to lethal doses of several different influenza viruses,” including ones that weren’t in the cocktail. The mice nonetheless showed “significant protection” from the flu viruses.

These efforts are promising, but even if they bear fruit, they’re still years from the doctor’s office. For now, the best we can do is get the flu shot that’s available and does provide some significant protection, wash our hands frequently with soap and water, and generally take good care of our health. We also can cheer on the scientists whose work might go far in protecting the public from a disease that kills tens of thousands of Americans each year.

 

YOU MIGHT ALSO LIKE:

Colorful Facts About Vaccination 

Another Benefit of Vaccines: Milder Disease 

Could Be a Rough Flu Season. Let's Get Ready! 

 

 

 

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