How to Make the Flu Vaccine Better


So far in the 2016-2017 flu season, there have been over 144.6 million flu shots given in the United States. That’s about the population of Russia! About 25,600 people have gotten sick enough to be tested and they tested positive for the flu. That’s about half the capacity of yankee stadium! Now most of the people that get the flu are people that haven’t gotten the vaccine, but even though you get the vaccine… There isn’t a 100% guarantee that you’re not going to get the flu. That really makes me wonder if the flu vaccine that we have right now is the best it can be or… Can we make the flu vaccine better? When we get the flu vaccine it causes us to make antibodies against the flu. These antibodies are protection for when we come across the virus in our daily lives… But we can only make antibodies against what were presented in the vaccine. A new paper from nature medicine suggests that the antibodies were making aren’t as good as they could be. That’s because the flu virus that we grow for the vaccines are grown in eggs. This paper recommends that instead of growing virus for the vaccines in eggs… we should start growing them in human cells in a dish. In order to get why eggs might be the problem, we should learn a little more about the flu vaccine… and why we use eggs in the first place. You might have heard that the flu vaccine is a better or worse match for the flu depending on the year. Each year three or four different types of flu virus are chosen to go into the vaccine. Those three or four different viruses are chosen really carefully to make sure that the vaccine causes people to make antibodies that will have the most protective effect. But occasionally… the flu that ends up infecting people isn’t the one that’s found in the vaccines. This makes the vaccine less effective and not a good match. The types of flu are labeled by H#N# The H and N refer to proteins on the surface of the virus. So when you hear H1N1 or H5N1… that means that those are two different types of flu virus that have the same N protein, but different H proteins like the two that you see here. So that’s all good information about the flu virus… but where do the eggs come in? In order to make enough virus for the approx 160 million vaccine doses made every year… they need a way to replicate the three or four viruses chosen fast, easy, and cheap. That’s where the eggs come in! The eggs used to make viruses for vaccines are fertilized chicken eggs and it takes about one egg make one dose of vaccine. Using an egg to make a virus is actually pretty easy. You simply inject a little bit of the virus that you want to grow into the egg and let incubate for a few days. After a few days you collect the liquid inside. That liquid now contains over 1 Billion flu viruses! It’s kind of like planting an appleseed to get a tree full of apples… only much faster and way more efficient! After collecting all those viruses, you purify and treat them so that they’re dead. Then they’re ready for the vaccines! Making viruses for vaccines in eggs is easy, cheap, and clearly very effective given how few people actually get the flu each year. So why change? According to researchers at Harvard and the University of Texas, the flu that you put into the eggs isn’t always exactly the flu that you end up with afterwards. The flu virus has a protein on its surface that helps direct it to the type of cell it should infect. For human cells that has a human specific protein. For birds, it has a bird specific one. It’s kind of like having different keys for different doors even though they’re both keys… they are specific to the type of door they open. Thanks to these researchers and others in the field we now know that when we grow our vaccine virus in eggs we’re actually picking out flu virus that has a more bird-specific protein than a human-specific one. This means that the antibodies we make in response to the vaccine are also more bird-specific than human-specific. To find this out, the researchers took a close look at the antibodies made by three different people in response to the flu vaccine. They then took these antibodies and tried them against the egg-grown flu that’s used for the vaccine and the flu that infects humans before it was ever put into an egg. One of the antibodies they tested was over 1,000 times more effective against the egg grown flu than it was against the flu that had never been grown in eggs… even though that flu is the one that makes us sick! That huge effect was only seen with one antibody, and most of the antibodies weren’t affected by the virus being grown in eggs… but if we can make the flu vaccine even better… why not try? Right now it’s clear that our vaccines from flu virus grown in eggs work really well, but it might be time to upgrade the way we make the vaccines from growing them in eggs to growing them in human cells in a dish. Of course more research needs to be done on whether the antibodies made as a result of the cell grown flu virus are actually better and worth the switch from eggs, but the preliminary data suggests that we really should consider the switch. Maybe in the near future our already good flu vaccine can be even better! Thanks for watching! If you want to keep learning about viruses feel free to check out my video on HIV! Please subscribe to my channel if you enjoy my videos and feel free to check me out at simplebiologist.com for more updates. See you next time!

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