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What’s In The Measles Vaccine?

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In the 1950s, 3 to 4 million people got measles every year in the United States. Scientists developed a vaccine for the highly contagious respiratory disease in 1963, and by 2000, the disease was effectively eliminated from American soil. But unvaccinated people continue to contract the disease. A particularly bad outbreak occurred in Ohio’s Amish country last year, infecting more than 300 unvaccinated people, and an exposure incident at Disneyland in California last month has already infected more than 100 people in 14 states, mostly children whose parents do not believe vaccines are safe.

Pharmaceutical company Merck manufactures the measles vaccine in the United States. Each vaccine also includes inoculations against the mumps, another contagious disease, and rubella, also known as the German measles. Each 0.5-milliliter dose of the combo vaccine, known as MMR II, contains 10 ingredients. We chatted with Vincent Racaniello, a professor of microbiology and immunology at Columbia University, to find out what exactly those ingredients are and what they do. Racaniello has worked with viruses for the past 35 years.


Measles Virus
To make a vaccine against a disease, which is caused by a virus, scientists first must grow it in a lab. “Every vaccine is different, but they all basically start as cells growing in a plastic dish with a liquid medium on top,” Racaniello says. “The cells are infected with the virus and over the course of a few days, the virus grows. Scientists harvest the medium on top of the cells, where the virus is, and that’s what they use for the vaccine.”

The strain of measles used for the measles vaccine, known as Edmonston, is derived from the original 1960s vaccine. Scientists use chick embryo cells to culture the virus. The liquid growth medium on top is known as Medium 199, a salt solution that includes vitamins, amino acids, and fetal bovine serum, plus sucrose, phosphate, glutamate, neomycin, and recombinant human albumin (more on those ingredients below).

Mumps Virus
Mumps is grown the same way as measles: in chick embryo cell cultures and with the Medium 199 liquid growing medium.

Rubella Virus
Unlike the measles and mumps, rubella is grown on cells from human diploid lung fibroblasts, known as WI-38. “This is a cell line that has been around for many years,” Racaniello says. “It was done once and then these cells keep growing in cultures forever. You keep them in your freezer in your lab. So you don’t have to get a human lung every time you make a vaccine.”

Rubella is grown in Minimum Essential Medium, a salt solution that contains vitamins, amino acids, and fetal bovine serum, plus recombinant human albumin, and neomycin.

Sorbitol is a stabilizer. It is also used as an artificial sweetener in food. “It’s added to the vaccine to keep the viruses from falling apart as they’re handled,” Racaniello says.

Sodium Phosphate
Sodium phosphate, or salt, is used as a buffer to maintain the vaccine’s pH level when it is frozen or thawed. “Vaccines are provided [to hospitals and doctors from the manufacturer] frozen,” Racaniello says. “They are frozen until they need to be used. When you thaw them, sometimes the pH can change and that would not be good for the infectivity. Often even in a frozen state the pH will change, but especially when you thaw it. Sodium phosphate, the buffer, maintains it at pH 7, which is where they want to keep it.”

Sucrose, or sugar, is a component of the liquid growth medium that the cells were originally grown in. Sucrose is the cells' energy source. “The growth medium provides the cells with the nutrients they need,” Racaniello says. “It has a variety of things in it, including sucrose, and because we make a vaccine out of that medium, those components are also present in the vaccine.”

Sodium Chloride
Sodium chloride, another salt, is also from the cell culture medium. “It’s there to make sure the medium is isotonic,” Racaniello says. “Cells have a certain amount of salt in them and the medium has to match. It’s just like when you get an intravenous drip and they use a saline or sodium chloride solution that matches the composition of your body fluids. This is here to match the composition of the cells on which the viruses are grown.”

Hydrolyzed Gelatin
Like sorbitol, hydrolyzed gelatin is a stabilizer to make sure the viruses stay infectious. “Gelatins are long chain molecules,” Racaniello says. “Hydrolyzed means it has been broken up into smaller components and that makes it more effective as a stabilizer.”

Recombinant Human Albumin
This protein is another component of the cell culture medium, which helps the cells grow properly. “Human albumin is found in blood,” Racaniello says. “Recombinant means it is made in a highly purified manner without contaminants.” To make the albumin, scientists put a gene for a human albumin in a cell and grow it in a lab. Once the cell produces the albumin, scientists can collect it and purify it directly from there, as opposed to stripping it directly from a blood sample, which could contain many contaminants.

Fetal Bovine Serum
Fetal bovine serum, which is collected from cow blood, is also a carry-over from the cell growth medium. “It’s very rich in growth factors,” Racaniello says. “We actually don’t know all of the different factors that are needed for cells to grow and culture. Otherwise we could make them in a lab and mix them all together. That’s why we still use serum from an animal to do that.”

The vaccine’s ingredients include items that help it grow in the lab and help keep it together in a vial. So what happens to them once they’re injected into your body?

The MMR vaccine is typically injected subcutaneously, where it begins to diffuse into your tissues and reach the lymph system. “The lymph system is composed of very permeable capillaries that take up anything that’s floating around in the tissues,” Racaniello says. Next the vaccine would enter a lymph node, which is a collection of immune cells. When the immune cells detect a foreign product such as the viruses contained in the vaccine, there is usually an immune reaction. “If you get a shot in the arm and you get sore, that’s because you’re having a little immune reaction to the components,” Racaniello says. “That’s actually good because it tells you that it’s working.”

Eventually the virus would spread throughout your entire body. “These are infectious viruses, so they would replicate in certain kinds of cells and produce more viruses, which would give you a really good immune response,” Racaniello says. “That’s why the vaccines work so well; because they’re infectious viruses.” Those viruses that your body produces will not give you measles or mumps or rubella, but they will alert your immune system to start making antibodies to defend against them. Then, if you ever got infected with measles or mumps or rubella, those antibodies would be there to block infection.

As for the other components, they diffuse throughout your entire body within a few minutes. “All of those things get immediately diluted so you wouldn’t have any sense that they’re there anymore,” Racaniello says. “Vaccines are great. They prevent diseases. This one has been used for a long time and it’s really unfortunate that people aren’t using them as much as they should. These infections can be lethal.”

Sources: CDC, Merck, Dr. Vincent Racaniello, Higgins Professor in the Department of Microbiology & Immunology, Columbia University

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Big Questions
Why Do Cats Freak Out After Pooping?
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Cats often exhibit some very peculiar behavior, from getting into deadly combat situations with their own tail to pouncing on unsuspecting humans. Among their most curious habits: running from their litter box like a greyhound after moving their bowels. Are they running from their own fecal matter? Has waste elimination prompted a sense of euphoria?

Experts—if anyone is said to qualify as an expert in post-poop moods—aren’t exactly sure, but they’ve presented a number of entertaining theories. From a biological standpoint, some animal behaviorists suspect that a cat bolting after a deposit might stem from fears that a predator could track them based on the smell of their waste. But researchers are quick to note that they haven’t observed cats run from their BMs in the wild.

Biology also has a little bit to do with another theory, which postulates that cats used to getting their rear ends licked by their mother after defecating as kittens are showing off their independence by sprinting away, their butts having taken on self-cleaning properties in adulthood.

Not convinced? You might find another idea more plausible: Both humans and cats have a vagus nerve running from their brain stem. In both species, the nerve can be stimulated by defecation, leading to a pleasurable sensation and what some have labeled “poo-phoria,” or post-poop elation. In running, the cat may simply be working off excess energy brought on by stimulation of the nerve.

Less interesting is the notion that notoriously hygienic cats may simply want to shake off excess litter or fecal matter by running a 100-meter dash, or that a digestive problem has led to some discomfort they’re attempting to flee from. The fact is, so little research has been done in the field of pooping cat mania that there’s no universally accepted answer. Like so much of what makes cats tick, a definitive motivation will have to remain a mystery.

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Jonathan Daniel/Getty Images
Big Questions
Why Do Baseball Managers Wear Uniforms?
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Jonathan Daniel/Getty Images

Basketball and hockey coaches wear business suits on the sidelines. Football coaches wear team-branded shirts and jackets and often ill-fitting pleated khakis. Why are baseball managers the only guys who wear the same outfit as their players?

According to John Thorn, the official historian of Major League Baseball since 2011, it goes back to the earliest days of the game. Back then, the person known as the manager was the business manager: the guy who kept the books in order and the road trips on schedule. Meanwhile, the guy we call the manager today, the one who arranges the roster and decides when to pull a pitcher, was known as the captain. In addition to managing the team on the field, he was usually also on the team as a player. For many years, the “manager” wore a player’s uniform simply because he was a player. There were also a few captains who didn’t play for the team and stuck to making decisions in the dugout, and they usually wore suits.

With the passing of time, it became less common for the captain to play, and on most teams they took on strictly managerial roles. Instead of suits proliferating throughout America’s dugouts, though, non-playing captains largely hung on to the tradition of wearing a player's uniform. By the early to mid 20th century, wearing the uniform was the norm for managers, with a few notable exceptions. The Philadelphia Athletics’s Connie Mack and the Brooklyn Dodgers’s Burt Shotton continued to wear suits and ties to games long after it fell out of favor (though Shotton sometimes liked to layer a team jacket on top of his street clothes). Once those two retired, it’s been uniforms as far as the eye can see.

The adherence to the uniform among managers in the second half of the 20th century leads some people to think that MLB mandates it, but a look through the official major league rules [PDF] doesn’t turn up much on a manager’s dress. Rule 1.11(a) (1) says that “All players on a team shall wear uniforms identical in color, trim and style, and all players’ uniforms shall include minimal six-inch numbers on their backs" and rule 2.00 states that a coach is a "team member in uniform appointed by the manager to perform such duties as the manager may designate, such as but not limited to acting as base coach."

While Rule 2.00 gives a rundown of the manager’s role and some rules that apply to them, it doesn’t specify that they’re uniformed. Further down, Rule 3.15 says that "No person shall be allowed on the playing field during a game except players and coaches in uniform, managers, news photographers authorized by the home team, umpires, officers of the law in uniform and watchmen or other employees of the home club." Again, nothing about the managers being uniformed.

All that said, Rule 2.00 defines the bench or dugout as “the seating facilities reserved for players, substitutes and other team members in uniform when they are not actively engaged on the playing field," and makes no exceptions for managers or anyone else. While the managers’ duds are never addressed anywhere else, this definition does seem to necessitate, in a roundabout way, that managers wear a uniform—at least if they want to have access to the dugout. And, really, where else would they sit?

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