Measles, a highly infectious viral illness, is an extremely unpleasant illness that can sometimes lead to very serious complications. While it mostly has been eradicated in the UK, it has been mentioned recently in the news due to measles outbreaks in the Democratic Republic of the Congo, increases in infection rates in the UK due to fewer people being vaccinated for it, and also research that discovered how being infected with measles can decimate your immune system.
Measles is contracted when a person is exposed to the measles virus (Measles morbillivirus), usually through the air due to droplets sprayed into the air when someone who is infected with measles coughs.
The virus then replicates just as any other virus would, in accordance with the six stages of virus replication. Firstly the viral proteins on the surface of the capsid (the protein coat surrounding the virus) interact with receptors on the cell surface membrane of one of your cells. Next, the virus attaches to a specific receptor, causing changes in the capsid surrounding the virus. As such, this results in the fusion of the viral membrane and the cell surface membrane. After that, the viral capsid is removed by enzymes, causing the viral genetic material to be released into the cell. Then, the genetic material of the virus replicates and the host human cell then starts producing viral proteins. These are then packaged to produce new virions. Finally, the virions are released. This can either happen by lysis, where the infected host cell dies, or by budding, which doesn't harm the infected cell. Symptoms of measles include cold-like symptoms, such as a runny nose, coughing and sneezing, as well as red eyes, running a high temperature, and small greyish-white spots on the inside of your cheeks. When the illness develops, it leads to a red-brown blotchy rash spreading across the body.
The measles virus can infect anyone, however, it is much more common in those who have not been vaccinated and those who have not had it before. This is mainly due to the fact that those who have not been infected or vaccinated do not have memory cells that can quickly release the necessary antibodies, stopping the infection from spreading before it causes symptoms. Furthermore, the condition is also prevalent among young children due to their less developed immune system.
Due to the fact that measles is highly contagious (90% of unvaccinated people who are near an infected person will become infected themselves), outbreaks of measles can quickly spread and become epidemics. This is most evident in the Democratic Republic of the Congo. Tragically, in 2019, almost 5000 people have been killed in the DRC by measles, with about 250,000 people having been infected. Indeed, these statistics mean that measle in the DRC have killed over twice the number of people that Ebola has in the same time period (read my post on Ebola to find out more).
As such, we have to ask ourselves how we can combat this and save more lives in the DRC by preventing this epidemic from becoming worse. The main barriers to stopping the spread of measles in the DRC are that the poor infrastructure and violence in the region cripple any public health initiative in the area. This means that, not only do hospitals not have the funds or training to properly treat/contain these diseases but that vaccinations can't be distributed around the country. As such, I propose that the Congolese government needs to be supported by charitable aid from foreign countries. This aid should be channelled through foreign non-governmental organisations (such as Médecins Sans Frontières, a medical charity that has several huge projects in the DRC) in order to reduce the impact of corruption in the region. While the Congolese government in collaboration with the World Health Organisation have launched an emergency vaccination program in the DRC to inoculate 800,000 children, without development to the DRC's infrastructure, not only will this epidemic not be contained, but future epidemics will be just as hard to control.
The MMR vaccine is routinely given to all children in the UK as part of your childhood vaccinations. After 2 doses of the vaccine, less than 1 in 100 children are at risk of being infected by measles, mumps or rubella. However, despite these life saving statistics, MMR vaccination rates have been falling in the UK over the last few years. Indeed, among children aged 2 years old in England, their vaccination rate has dropped from 91.2% in 2017-2018 to 90.3% in 2018-2019, the lowest it has ever been since 2010. As such, the UK is no longer classified as a measles-free country. Furthermore, worldwide, a fall in vaccination rates has resulted in a 300% increase in measles infections since 2018.
Earlier this year, researchers at Harvard Medical School examined volunteers from three schools in the Netherlands to determine the effect measles infections have on the rest of a child's immune system. What they discovered was that measles severely restricts the diversity of immune cells we have. Normally, the human immune system produces thousands of different varieties of immune cells, each with different receptors on their surfaces. As such, our immune system can recognise and destroy the majority of pathogens that we encounter. Furthermore, towards the end of fighting each infection, some of your T-cells and B-cells turn into memory T-cells and B-cells. These cells usually remain in your bloodstream for a long time after infection and, like their name suggests, they remember the pathogens they fought. Because of this, they can quickly release the correct antibodies, meaning a future infection can be treated both more rapidly and more effectively.
However, researchers discovered that a measles infection resulted in a phenomenon they called "immune amnesia". This means that large quantities of memory cells in the children's bloodstream had disappeared. On average, this was around a 20% reduction in the number of antibodies they could produce. One child who'd had severe measles infections saw a reduction of 73%. As such, after a measles infection, not only are people much more susceptible to common illnesses, but they also may have lost the memory cells that were produced in response to childhood vaccinations, such as vaccinations against tetanus and meningitis. Nevertheless, according to these researchers, children are likely to recover from this, just as those who have to take immunosuppressant drugs can recover from their impact. Moreover, this research mainly focused on B-cells and largely ignored T-cells (another type of cell involved in your immune system). While experts suggest that measles can also impact these T-cells, research has not yet been carried out on them.
To conclude, measles infections underline the impact that not being vaccinated can have. Not only can it lead to death from contracting the specific illness the vaccine is intended for, but also, in the case of measles, it can lead to death from immune amnesia. Nonetheless, I must stress that the MMR vaccine does not cause immune amnesia - in fact, having the MMR vaccine reduces the risk of getting immune amnesia. As such, the governments of the world must prioritise vaccination initiatives, as well as supply these vaccinations and the means required to distribute them in a sustainable way to poorer countries. As such, by working together, we can reduce the spread of infectious diseases and save lives across the globe.
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