Eliminating Measles is Everyone’s Problem. Here’s Why.

History

Measles is one of the oldest infectious diseases. First documented by a Persian doctor in the 9th century, it is responsible for millions of deaths throughout history. In the 18th century, there was an initial scientific breakthrough. A Scottish physician named Francis Home demonstrated that the disease was caused by an infectious agent in patients’ blood [6].

By 1912, measles became a notifiable disease in the United States. Since then, around 6,000 measles-related deaths have been reported in the country each year. But, it was only in 1954 that the causative agent of the disease was first isolated by John F. Enders and Dr. Thomas C Peebles during a measles outbreak in Boston, USA. They successfully isolated the measles virus from the blood of a 13-year-old student while researching to develop a vaccine [6].

The measles vaccine was licensed in the United States in 1963. A few years later, in 1968, an improved version of the vaccine was developed by Maurice R. Hilleman and his colleagues [6]. In 1971, Hilleman combined the measles, mumps, and rubella vaccines into one vaccine — MMR (Measles Mumps Rubella). Since then, it has been administered as a single shot. In 2005, scientists added the varicella vaccine to the MMR combination, and it became known as the MMRV (Measles Mumps Rubella Varicella) vaccine [7].  For his achievements, Hilleman is known by some as the ‘father of modern vaccines.’ He was also responsible for developing vaccines for hepatitis A and B, varicella, meningococcus, and pneumococcus. 

In 2012, the World Health Assembly, the decision-making body of WHO, issued an action plan to eradicate measles in four high-risk regions by 2015 through vaccination. According to the WHO, the vaccination program was highly successful and resulted in a 73% reduction in measles-related deaths by 2018. However, measles outbreaks continue to ravage specific regions of the world, even today [8].

Epidemiology

The measles virus continues to circulate in many parts of the world, including countries in Africa, Asia, Europe, the Middle East, and North and South America [1,9].  The disease affects both men and women equally [1]. People at a high risk of contracting the viral infection are:

• unvaccinated children under five years of age
• unvaccinated adults over 20 years of age
• unvaccinated pregnant women
• people with weak immune systems [8,10]. 

Outbreaks

The seasonality of measles outbreaks varies from region to region. In temperate regions, measles outbreaks usually occur in late winter and early spring. In the tropics, outbreaks are more common in dry seasons [12]. In the pre-vaccination era, the world witnessed significant measles epidemics every two to three years. Worldwide, there were 2.6 million measles-related deaths reported annually [8]. During this time, most children became infected by the time they attained 15 years of age [6]. 

According to the Centers for Disease Control and Prevention (CDC), around 3 – 4 million people were infected in the US alone each year before vaccines were discovered. There were around 48,000 hospitalizations and around 400 to 500 deaths every year. Around 1,000 people suffer from acute encephalitis – a severe complication from measles that causes deafness or intellectual disability in children [4,6,9].   

In 2018, the world witnessed a sudden rise in measles-related deaths, double the previous year’s. Around 140,000 people, mostly children under five, died from measles-related complications. These preventable deaths were due to low vaccination coverage in endemic countries like the Democratic Republic of Congo, Liberia, Madagascar, Somalia, and Ukraine. The WHO notes that these five countries were responsible for almost half of the total measles cases worldwide. 

Unfortunately, during the COVID-19 pandemic, vaccination efforts stalled worldwide, resulting in a new surge of measles. In 2019, there were 869,770 cases, with 207,500 deaths reported – the highest number of measles cases in over two decades. Deaths this year were 50% higher than a historic low in 2016. The US experienced 22 measles outbreaks, with a total of 1,282 cases being reported across the country. This was the country’s first recorded over a thousand cases since it was declared eliminated in 2000 [9,11]. According to the CDC, most cases were found in unvaccinated communities.  

As the COVID-19 pandemic raged, 23 million children missed out on basic childhood vaccines in 2020. This is the highest number since 2009 and is 3.7 million more than in 2019, as reported by UNICEF (United Nations Children’s Fund). Africa remains an endemic region for measles even today. In 2022, a measles outbreak in Zimbabwe infected over 6,500 people and killed over 700 children. It is the second-deadliest outbreak in Africa after 2010 (when over 7,754 were infected and 517 died) [16]. The biggest reasons for this tragic outbreak were a massive drop in vaccinations due to the COVID-19 pandemic and growing religious opposition to the vaccines. 

How is it Spread?

The measles virus is highly contagious. Only a small viral load is needed to infect a person [13]. Almost 90% of people in contact with a person infected with measles get sick if they are not immune to the virus. This group includes those who are unvaccinated and those with a weak immune system. This is because the virus can remain active in the air or on surfaces for up to two hours. A person can transmit measles four days before the rashes appear and can continue to spread the infection for up to four days following the onset of rashes. 

Measles is spread when:

• An infected person coughs or sneezes. The virus particles are released into the air, and when an uninfected person inhales the contaminated air, they become infected.
• People touch surfaces contaminated with the measles virus and then touch their eyes, mouth, or nose [4,8].
• A person gets in direct contact with the respiratory secretions of an infected person [1].

Biology of the Disease

The measles virus usually enters the human body through the respiratory tract. After initially infecting the respiratory epithelial cells, the virus continues to replicate [13,14]. After that, local lymphatic tissues are affected. The viral load in the lymph nodes is amplified and eventually released into the bloodstream. 

This way, the virus travels to different parts and organs of the body, including the gastrointestinal tract, kidney, liver, and skin. In the organs, the virus replicates in the endothelial, epithelial cells, and macrophages, increasing the severity of the infection [13].  One reason why measles is so deadly is that it also suppresses the immune system. This makes infected individuals more susceptible to other infections, even ones they were immune to in the past [13]. 

Symptoms

It usually takes 1-2 weeks for the symptoms to appear following exposure to the infection. Measles symptoms usually begin with:

• High fever that usually lasts for four to seven days
• Cough
• Running nose
• Red and watery eyes.

Small white spots (also called Koplik spots) appear inside the cheeks two to three days after the onset of symptoms. Rashes also appear on the face and eventually spread to other parts of the body, including the neck, trunk, hands, legs, and feet, 3-5 days after the initial symptoms appear. At this phase, people usually have a high fever (over 104° Fahrenheit) [8,15]. Some of the complications that might arise as a result of severe illness include:

• Ear infections – mostly observed in children
• Diarrhea
• Pneumonia – a common cause of measles-related deaths in young children
• Encephalitis (swelling of the brain) – may cause deafness or intellectual disability in children. It can also cause convulsions
• Infected pregnant women might give birth prematurely or might give birth to under-weight babies
• Death due to respiratory and neurologic complications are possible
• Sub-acute sclerosing panencephalitis (SSPE) is one of the more severe, long-term complications caused by measles. It is a fatal disease of the central nervous system that could affect a person 7-10 years after recovering from measles [10]

Diagnosis

A person can be suspected of having measles based on early symptoms. Learning about their recent travel history can help. If they have been in recent contact with people with high fever and rashes, physicians can make a reasonable judgment [1].

For a more accurate diagnosis, laboratory confirmation is needed. Serological tests can be performed to look for measles-specific antibodies. Also, RT-PCR can be performed to detect measles RNA in the respiratory specimen of the person suspected to be infected by the virus [1,9].

Sometimes, it can be difficult to distinguish between a rash caused by a measles vaccine and a measles virus. In such cases, a molecular analysis can help find the root cause [9].

Treatment

There is no specific antiviral treatment for measles to date, which is why vaccines are essential. Depending on the severity of the disease, supportive or symptomatic treatment can relieve symptoms and deal with complications. 

So, the existing treatment focuses on reducing fever, keeping the patient hydrated, providing a nutritious diet, and ensuring that all other infection control measures are followed. Antibiotics can help treat secondary bacterial infections [1].

Vitamin A is generally administered as soon as a child is diagnosed with measles. This is because vitamin A is found to reduce mortality and morbidity significantly. Depending on the age of the child, the following dosages of vitamin A are administered orally once daily for two consecutive days:

• For infants less than 6 months of age – 50,000 IU
• For instance, between 6 to 11 months of age – 100,000 IU
• For children who are 12 months and older – 200,000 IU [1,9].

Prevention

The two-dose measles vaccine is one of the greatest armor available to protect against measles-related complications. It has been in use for over 60 years. It is usually administered with rubella and mumps vaccines (MMR) and even varicella (MMRV). The vaccine is safe and effective when administered as a single component or combined. 

The WHO recommends two doses of the vaccine for better effectiveness. This is because 15% of children don’t develop enough immunity after the first dose [8]. A vaccine shot can be given to those suspected of being infected by the virus. It should be given within 72 hours of exposure to the virus to help prevent infection or stop an existing one from becoming a more severe illness [1].

Other preventive measures to protect against the spread of measles include:

• Regular washing of hands and avoiding touching eyes, mouth, or nose with unwashed hands
• Healthcare workers in hospitals and clinics should wear face masks or respirators while handling patients who are infected or suspected to be infected by the virus
• Infected people should be completely isolated from others. They should stay away from public places for at least four to seven days following the onset of rashes [1].