If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:9:02

Video transcript

the HIV vaccine was developed in 1985 and it's a vaccination for Hamas influenza type B now this specific strain of this bacteria Moff lewis influenza was very serious it could cause severe complications and diseases for example this strain could cause severe meningitis which is swelling of the tissue that surrounds the brain and it could also cause pneumonia which is swelling of the lung tissue caused by this bacterial infection and epiglottitis which is swelling of the epiglottis which is that little covering that folds over the airway whenever we swallow so that food doesn't get into our lungs before the development of this vaccine about 40 to a hundred of a hundred thousand people could become infected by this strain of hemolysis influenza now that may not seem like a lot but because it causes such severe conditions and also because it primarily affects newborns and children this was a very serious public health concern but after the development of this vaccine that number was reduced to less than one case per a hundred thousand people per year so that's a reduction from about point zero four percent of the population to point zero zero zero one percent of the population which is a dramatic difference now the way this vaccine works is by inducing an immune response to a specific polysaccharide sequence that is found on this specific strain of homophonous influenza so what all that means is essentially there is a carbohydrate sequence and this is commonly found on the surface of the bacteria now since this polysaccharide sequence this carbohydrate sequence is found specifically on the type B strain of homophily influenza we want to target this sequence because if our immune system can recognize this if the real deal comes along then we'll be able to eliminate this however the problem with a polysaccharide sequence is it doesn't produce a large immune response our body is better at recognizing foreign proteins rather than car hydrates and so what we do to amplify this response is we attach a little protein with a molecular bond to link the two together this conjugation this combining of these two the polysaccharide and the protein is called a conjugate they're combined together so this type of vaccine is a conjugated vaccine that creates a larger immune response and due to this conjugation the HIV vaccine is more than 95 percent efficacious meaning it's very effective against stopping the bacteria but keep in mind this is all for only the type B strain all the other types of Hamas influenza can still afflict the patient but it's really the type B strain that's the most severe and so it's good that we were able to develop a vaccine for it now like I said our immune system can recognize foreign proteins much better than it can polysaccharides so this creates a huge immune response and causes white blood cells known as macrophages to recognize this and engulf it macrophage means big eaters so these big eaters eat up this polysaccharide and protein link and once these guys do that they'll travel all the way down the bloodstream into lymph nodes and in those lymph nodes are specialized white blood cells and these specialized white blood cells are called t-cells once macrophages present this material to T cells the T cells become activated and these activated T cells will let other cells known as b-cells know that there's something going on here b-cells are famous for creating antibodies and antibodies are little Y shaped proteins that recognize specific sequences and in this case these b-cells these antibodies that they create recognize the specific sequence for these proteins and polysaccharides and so that's how the immune response is generated and another way to create a greater response is to introduce this protein and polysaccharide mix multiple times now before I go into the dosing let me highlight this again remember this is the h i Mullis influenza strain B polysaccharide now to create a really good immune response these proteins are often from other viruses or products from bacteria so for example some bacterias create a toxin such as diphtheria pertussis or tetanus which is essentially a protein that creates a huge immune response so there are actually a lot of vaccines out there for hemolysis influenza type B and they may be paired with different types of toxins whether they're tetanus pertussis diphtheria sometimes this protein can be an inactive virus so hepatitis B all sorts of different combinations and it's also very useful to pair these different proteins and polysaccharides because not only will the patient get immunization from Buffalo influenza but they'll also get immunization from these other bacteria or viruses that are paired with this polysaccharide sequence now in order to generate a very strong immune response and since a polysaccharide sequence generates a very weak response the Hib vaccine needs to be dosed three times and then again with an additional booster vaccine a booster essentially contains the same components but it reminds the immune system hey you need to keep creating antibodies keep creating these little signal markers to identify this polysaccharide sequence and allow the immune system to destroy it and since newborns and very young children at are at a higher risk for hemolysis influenza strain be the first dose starts at two months of age after that initial dose it's recommended that the patient gets another dose four weeks after that initial dose so four weeks will be about at four months and then six months and remember this is all to create a very strong immune response to make sure that the baby has immunity against this bacteria after these three doses the final booster dose is recommended at fifteen to eighteen months of age now what if the patient actually misses one of these doses what if the child is about four months old well that's okay you can start the dosing at four months and then just have an extra dose four weeks from then so if the child gets the first dose at four months they should receive the next dose at six months and then the next dose at eight months and then follow up with a booster at 15 to 18 months now if the child is about 7 to 11 months old then will actually skip one of these doses and again the reason for that is because these doses are trying to get the baby through the first months of life without being infected by this bacteria so if they're already 7 to 11 months old we just need to get them through a couple more months before they get their booster shot so a 7 to 11 month old will only need two vaccines plus the booster and if the child is 12 to 14 months old then they'll only need one shot plus the booster and if the child has missed all the opportunities to get these regular shots so if around 15 months to 5 years old then all they need is just one shot which would be the booster shot and finally since children normally develop immunity to Buffalo's influenza type B after 5 years old if they're older than 5 then they no longer need to get the vaccine unless they're immunocompromised then they may actually need to get the vaccine now with any vaccine there can be some adverse effects but for vaccines such as this the benefit really does outweigh the risk some more common adverse effects include local pain or redness or swelling around the area of injection and patients may also develop a fever they may become fussy or very irritable and these symptoms may actually be common up to 25 percent of patients may actually have some of these symptoms but thankfully these usually go away between 24 to 48 hours still it's important to report these symptoms to the physician so that they're aware of any adverse effects and can act quickly if symptoms become worse or do not go away now more severe symptoms are the neurological symptoms these symptoms include extreme lethargy inconsolable crying paralysis of the limbs seizure convulsions very severe adverse effects or if a patient develops difficulty breathing or severe rash or a fever over 105 degrees Fahrenheit or 40 degrees Celsius is very serious but thankfully these symptoms are very rare and don't occur in patients very often and as I said the benefit of the vaccine highly outweighs the risk otherwise the patient may develop severe illnesses such as meningitis pneumonia or epiglottitis which can be very life-threatening illnesses