By: Megan Tseng
What comes to mind when you see the word “measles?” Perhaps, you have a vague memory of hearing about it at the doctor’s office before receiving a vaccination, or from a public health service announcement. In all honesty, you’ve probably filed this name away with other diseases that are seemingly irrelevant to us today, like chicken pox and typhoid fever. After all, most folks simply imagine it to be an obscure, long-forgotten disease the world got rid of a good while ago.
Regardless of what you think of it, the fact remains that measles is slowly but surely making its comeback. As an airborne disease caused by a virus, measles is highly contagious and involves symptoms such as a high fever, runny nose, cough, irritation in the eyes, and a rash. Other more serious complications caused by measles include blindness, brain swelling, and severe diarrhea, which can possibly lead to death. According to the World Health Organization, before the measles vaccine was introduced in 1963, measles caused around 2.6 million deaths per year. Even in 2017, years after widespread vaccination, approximately 110,000 people died from measles.
Research
Recent studies have shown that the effects of measles may not be limited to just these symptoms.
In 2012, a team led by Erasmus University Medical Center virologist Rik de Swart conducted a study on the measles virus. They inserted a gene coding for a fluorescent protein into the measles virus, and introduced it to a macaque monkey. As the researchers followed the spread of the virus, they saw that the monkey’s lymphoid tissues were lit up with bright green fluorescent specks, indicating the presence of measles. Once the immune response was activated, the green dots disappeared, signalling the destruction of the measles-infected cells in the monkey’s lymphoid tissues.
The measles virus, shown as fluorescent green specks, concentrates in the lymphoid tissue of the monkey’s spleen.
When the Immune System Forgets
Among the lymphoid tissue cells that the measles virus hijacked were immune memory cells. When someone gets sick, these cells remember the infection and allow the immune system to launch a more effective attack if the body encounters it again. By targeting memory cells, measles essentially causes immune “amnesia,” in which the immune system “forgets” how to recognize and counter infections that it’s come across before. As a result, the immune system becomes vulnerable to pathogens that they would usually be able to eliminate automatically.
Confused? Think music. Let’s say you just started learning how to play a piece on the piano. You’d probably be unfamiliar with the pattern of notes in the music. Because of that, you would first have to look at each of the notes in the music, find them on the piano, and then play them one by one. You’d get a lot of the notes and dynamics wrong, and the tempo might be out of whack, too. Pretty exhausting, right? But once you’ve practiced it a hundred times through, you’d be playing it with near-perfect accuracy and expression. If someone sat you in front of a piano and told you to play that piece, you’d be able to do it right away, without even having to look at the music. That’s basically what memory cells do; they come across a pathogen in the body, remember it, and allow the body to attack it faster and better the second time around. But what if something happened and you couldn’t remember ever playing the piece before? It would knock you back to square one, and you’d have to relearn the piece all over again while making mistakes everywhere. That’s what happens when measles causes immune amnesia. When memory cells get wiped out, stored information about the body’s past infections is destroyed, weakening its responses to these infections.
The Vital Vaccine
It’s clear that the lingering effects of measles puts people at greater risk for other illnesses. Thus, prevention measures taken against measles can provide protection against a variety of infections.
The measles, mumps, and rubella vaccine is a widely accepted preventative measure used to counter measles.
The measles, mumps, and rubella (MMR) vaccine was introduced in 1963, and has been proven effective in preventing measles, mumps, and rubella. According to the CDC, the recommended two doses of the MMR vaccine are about 97 percent effective at preventing measles. Herd immunity, resulting from the widespread use of measles-containing vaccines, has allowed those immunized to provide protection for those unable to be vaccinated. In other words, the chances of being infected by measles has been drastically reduced by the large percentage of people who have been vaccinated against it. Statistically speaking, herd immunity has led to a greater than 99 percent reduction in measles cases thus far.
More importantly, the measles vaccine counters the detrimental effects of immune amnesia. Data shows that following widespread vaccination, cases of diseases such as pneumococcus and diarrhea dropped down to 50 percent in resource-poor regions, and as much as 90 percent in impoverished regions.
Despite the claims of anti-vaccination advocates, a single vaccine has the potential to protect us from many different diseases. When it comes to measles, vaccination is important for maintaining the health of both your body and immune system.
References
Harvard Medical School. (2019, October 31). How measles wipes out the body's immune memory. Retrieved November 29, 2019, from Science Daily website: https://www.sciencedaily.com/releases/2019/10/191031204630.htm
Measles vaccination. (2019, March 28). Retrieved November 29, 2019, from Centers for Disease Control and Prevention website: https://www.cdc.gov/vaccines/vpd/measles/index.html
Stenson, J. (2019, October 31). Measles virus could wipe out the immune system's 'memory,' new research suggests. Retrieved November 29, 2019, from NBC News website: https://www.nbcnews.com/health/kids-health/measles-virus-could-wipe-out-immune-system-s-memory-new-n1074636
Wei-Haas, M. (2019, October 31). Measles vaccines protect against more than just measles. Here's how. Retrieved November 29, 2019, from National Geographic website: https://www.nationalgeographic.com/science/2019/03/measles-vaccine-protect-disease-immune-amnesia/
[Figure 2. Schematic diagram of reverse genetics of wild-type MV expressing EGFP and infection of monkeys.]. (2012, January 30). Retrieved from https://www.frontiersin.org/articles/10.3389/fmicb.2012.00014/full
Getty Images. (2019, March 20). [Measles Mumps Rubella Vaccine]. Retrieved from https://www.aarp.org/health/conditions-treatments/info-2019/measles-older-adults.html