When your 12- to 15-month old gets the Measles, Mumps, and Rubella shot, what exactly is in the vial?
As rumors about the vaccine spread faster than the measles itself, we take a look at each of the ingredients that make up the inoculation.
We asked Dr. Mark Schleiss, director of Pediatric Infectious Diseases and Immunology at the University of Minnesota Medical School, and Sean O'Leary, an assistant professor of pediatrics at the University of Colorado, for the low-down on what makes up the MMR shot (including ingredients used to produce the vaccine that may be present in trace amounts).
Medium 199: This is the solution, developed in 1950, that allows the virus to grow. It contains amino acids, glucose, salt and vitamins.
Minimum Essential Medium: Containing electrolytes, glucose, and salt, the cell/s get bathed in this liquid to encourage them to grow. Trace amounts may remain in the vaccine.
Phosphate: An electrolyte that acts as a buffer in the vaccine. Phosphoric acid can be used as a preservative in foods, and it gives Coke its tartness, but we have phosphate in our bones, tissue, and blood.
Recombinant human albumin: The most abundant protein in human blood, albumin promotes the growth of the cells in cell cultures, and it stabilizes proteins and virus particles. "So if I purify 100 billion virus particles in my lab and stick them in a -80 degree freezer, when I thaw them six months later about 20 percent will be dead," Schleiss said. "But if I do the same experiment with albumin in it, the viruses will survive."
Neomycin: An antibiotic. If you've ever put a salve of Neosporin on a scraped knee, you've probably used about 140 times the amount of neomycin that's in the MMR, O'Leary calculated. It's present in vaccines to minimize any bacterial contamination of the tissue culture (it's used instead of an antibiotic such as penicillin or amoxicillin which have bigger resistance concerns).
Sorbitol: A sugar alcohol. It's naturally found in blackberries, raspberries, apples and other fruit. It's also used as a sweetener. "If you chew on a piece of sugarless gum, you swallow about a milligram's amount," Schleiss said. In the vaccine, it helps virus particles maintain their viability by stabilizing cell membranes, Schleiss said.
Hydrolyzed gelatin: Similar to what you might eat for dessert (without the artificial food dye), it helps hold everything together, "to stabilize the preparation so it's not too droopy," Schleiss said. Some parents, O'Leary said, express concerns that certain ingredients may be OK to eat but not injected. However, the amount that's injected is a fraction of what would be ingested orally.
Chick embryo cell culture: Cells of live viruses are often grown in cells of other species in order to "elicit the immune response but not cause the disease," Schleiss said. "The virus in the measles vaccine your child gets has somewhere in the range of 50-75 mutations and multiple different genes that make it unable to cause the disease." An 18th-century English country doctor discovered this when he realized that milkmaids, who were exposed to cowpox, seemed to be immune to the human version -- smallpox.
WI-38 human diploid lung fibroblasts: While the measles and mumps viruses can be grown in the cells of chick embryos, rubella can only grow in cells of human origin, Schleiss said. The cells used here originated from two terminated pregnancies in the early 1960s, and have reproduced in laboratories since then. Although that poses an ethical dilemma for some, the National Catholic Bioethics Center says "One is morally free to use the vaccine regardless of its historical association with abortion. The reason is that the risk to public health, if one chooses not to vaccinate, outweighs the legitimate concern about the origins of the vaccine. This is especially important for parents, who have a moral obligation to protect the life and health of their children and those around them."
Water: The bulk of the liquid in that half-milliliter vial is water.
O'Leary says he often discusses vaccine ingredient concerns with families.
"It's human nature to be afraid of what you don't understand," he said, "but all of these ingredients are well studied, and people who do understand them have no concerns about them."