Medical Briefings Measles

Transcription

Medical Briefings Measles
Medical
Briefings
Mmer
Measles
Measles is one of the most communicable infectious
diseases, with the potential for serious lifethreatening complications. In 1980, before
widespread vaccination, the measles virus caused
an estimated 2.6 million deaths worldwide.
The disease remains one of the leading causes of
death among young children globally, despite the
availability of a safe and effective vaccine. Also in
the most vulnerable groups are: adults over 20 years
of age; pregnant women; and people with
compromised immune systems, such as those with
leukaemia and HIV/AIDS.
The overwhelming majority (more than 95%) of measles deaths occur in countries with low per capita
incomes and weak health infrastructures – particularly in parts of Africa and Asia.
How is Measles Spread?
Measles is one of the most contagious viruses ever discovered. It is spread by coughing and sneezing, by
close personal contact or by direct personal contact with infected nasal secretions. Up to 90% of
susceptible persons in close contact with measles patient will develop measles.
The most remarkable thing about the virus is that it's incredibly indestructible. If you were unvaccinated,
you could catch the virus from droplets left in the air by an infected person who had coughed in the room
hours earlier. No other virus can do that. It also lives on surfaces for hours, finding new hosts in the
unimmunized.
It can be transmitted from 4 days prior to the onset of the rash, to 4 days after the rash erupts. The virus
infects the mucous membranes and then spreads throughout the body. Measles is a human disease and is
not known to occur in animals.
Signs and Symptoms of Measles
After an incubation period of 10 to 12 days, measles appears as a
fever, cough, stuffy/runny nose, and bloodshot and watery eyes.
Loss of appetite and low energy are common too. Several days
after these initial symptoms, an uncomfortable spotty rash begins
to spread all over the body, starting on the face and neck, and
moving downward - it also causes white spots on the inside of the
cheeks. The rash usually lasts for 3 to 5 days and then fades
away. In uncomplicated cases, people who get measles start to
recover as soon as the rash appears and feel back to normal in
about 2 to 3 weeks.
Signs and Symptoms




Fever (up to 105°F/41°C)
Cough
Runny or stuffy nose
Conjunctivitis (bloodshot,
watery eyes)
 Rash on face and body
 White spots inside cheeks
Complications of Infection
In most cases, measles is not deadly, but it's almost always debilitating, bringing on a weeks-long fever,
rash, and painful, watery eyes. Up to 40% of people experience complications, and 1 or 2 children in 1,000
die.
Common complications:
Middle ear infections leading to deafness
Pneumonia
Diarrhoea
Serious complications, especially in children:
Blindness
Encephalitis (swelling of the brain) often leading to permanent brain damage (~ 1 in 1,000)
Death from respiratory and neurological complications (~ 1 or 2 in 1,000)
Rarely, behavioural and mental deterioration and seizures 7-10 yrs after infection.
How is Measles Treated?
No specific antiviral treatment exists for measles virus. Severe complications from measles can be avoided
through supportive care that ensures good nutrition, adequate fluid intake and treatment of dehydration
with oral rehydration solutions. This solution replaces fluids and other essential elements that are lost
through diarrhoea or vomiting. Antibiotics may be prescribed in the event of eye and ear infections, and
pneumonia. Infected people should be isolated for 4 days after they develop a rash.
People who are at risk of severe illness and complications from measles, such as infants younger than 12
months of age, pregnant women without evidence of measles immunity, and people with severely
compromised immune systems, should receive immunoglobulin injections, where this is available.
All children in developing countries diagnosed with measles should receive two doses of vitamin A
supplements, given 24 hours apart. This treatment restores low vitamin A levels during measles that occur
even in well-nourished children and can help prevent eye damage and blindness. Vitamin A supplements
have been shown to reduce the number of deaths from measles by 50%. People who recover from
measles are immune for the rest of their lives.
Prevention
Routine measles vaccination for children, combined with mass immunization campaigns in countries with
high case and death rates, are key public health strategies to reduce global measles deaths. The measles
vaccine has been in use for 50 years. It is safe, effective and inexpensive. It costs approximately $1 US to
immunize a child against measles. Two doses of the vaccine are recommended to ensure full immunity
and prevent outbreaks, as about 15% of vaccinated children fail to develop immunity from the first dose.
The measles vaccine is often incorporated with rubella and/or mumps vaccines [MMR vaccine] in countries
where these illnesses are problems. Adding rubella to measles vaccine increases the cost only slightly,
and allows for shared delivery and administration costs. The measles vaccine is not licensed for use on
babies younger than 12 months. That means that, for the first year of life, babies depend on the fact that
everybody else around them gets vaccinated. This essentially creates a firewall: if other people are
vaccinated, they won't catch the disease - and won't spread it to young children who cannot get protection.
This is what scientists call "herd immunity," and it’s a huge reason why we get vaccines in the first place.
The shots aren't just about protecting ourselves from measles, mumps, the flu, or other diseases. They're
about making it really hard for those who are medically frail (like the elderly) and those who can't get the
vaccine (often babies and pregnant women) to catch a disease that could be devastating to them. The
vaccinated people form something like a fence around the vulnerable people, making it more difficult for
the disease to penetrate.
Can Measles be Eliminated?
Over the last 30 years, the incidence of the disease has dropped dramatically. In 1980, around 2.6 million
died globally from measles and by 2013 that number was just 145,700. But measles continues to circulate
around the world, even in places you don’t always think of as hot beds of deadly infectious diseases.
Measles outbreaks have been so bad in Europe that the World Health Organization has put out a strong
cry to policymakers, health workers and parents, asking them to immediately “step up vaccination against
measles.”
In the last 12 months there have been more than 22,000 cases of measles reported in Europe. This
included more than 3,000 cases in Russia, 1,674 in Italy, and nearly 600 cases in Germany, threatening
Europe’s goal of eliminating the disease by the end of 2015.
Measles Anywhere Means Measles Everywhere
In the US in the year 2000, measles was declared eliminated on the grounds that there was no endemic
measles transmission recorded for 12 months. However, measles is common in many parts of the world
and outbreaks have still occurred every year since, through returning travellers. Last year, more than half
of around 600 measles cases in the US were caused by a single unvaccinated Ohio man returning from
the Philippines - where the disease was circulating - and spreading measles to his similarly unimmunized
community. The US is currently experiencing a large, multi-state outbreak of measles that originated in
Disneyland in California. The outbreak started in December 2014 and has spread to more than a dozen
other states. And that’s exactly typical of how outbreaks start.
Debate is going on around the world, especially in affected communities, about the recommendations for
measles vaccination in populations. The dilemma hinges on whether or not the vaccination program should
be made compulsory. There have been claims in the past – later discredited – that the vaccines could be
linked to autism. Medical professionals and governments around the world say vaccination is safe and
recommend it as a preventative measure.
The WHO Fourth Millennium Development Goal (MDG 4) aims to reduce the under-5 year olds mortality
rate by two-thirds between 1990 and 2015. Given that measles vaccination coverage can be considered a
marker of access to child health services, routine measles vaccination coverage has been selected as an
indicator of progress towards achieving MDG 4. Overwhelming evidence demonstrates the benefit of
providing universal access to measles-containing vaccines.
The measles virus could theoretically be eradicated, never to infect another human again. That’s because
it fits the profile of diseases that can be eradicated: people, and not animals, are the only carriers of the
virus (so eradication wouldn't require killing off an entire animal species); there is an effective vaccine; and
there is a readily available and accurate diagnostic test to identify the disease.
Globally, there’s some good news on this front: during 2013, about 205 million children (84% of the world's
children) were vaccinated against measles during mass vaccination campaigns in 34 countries - an
increase from 73% in 2000. All WHO Regions have now established goals to eliminate this preventable
killer disease by 2020.
But this isn’t enough for total eradication. While most (about 95%) of today’s outbreaks occur in developing
countries, particularly in Africa and Asia, measles can take off anywhere, as has been seen in the Disney
outbreak, as long as there are enough people who did not get the vaccine.
Key Points
 Measles is one of the leading causes of death among young children even though a safe
and cost-effective vaccine is available.
 In 2013, there were 145,000 death from measles globally.
 Measles vaccination resulted in a 75% drop in deaths from measles between 2000 and
2013 worldwide.
 In 2013, about 84% of the world's children received one dose of measles vaccine by their
first birthday through routine health services – up from 73% in 2000.
 During 2000-2013, measles vaccination prevented over 15 million deaths making measles
vaccine one of the most cost effective successes in public health.
Ebola-Hit Countries at Risk of Massive Measles Outbreak
As the death rate from the largest ever outbreak of Ebola Virus passes 10,000, a study in the journal
Science suggests there could be even more deaths from other diseases because of the devastating impact
on the countries' vaccination programmes. Many healthcare facilities have closed and the fear of Ebola
meant people did not show up at those that remained.
It has had a knock-on effect on immunisation campaigns for measles, polio, TB and other diseases. An
international team of scientists ran detailed models assuming 75% of vaccination programmes had been
disrupted. They estimated that 20,000 more people were becoming susceptible to measles every month. At
the start of the outbreak they said there were 778,000 unvaccinated children and the total would increase
to 1,129,000 after 18 months of the outbreak.
Their sophisticated predictions suggested this would translate to an additional 100,000 measles cases, on
top of the 127,000 that would be anticipated in a pre-Ebola measles outbreak. It could lead to 16,000 extra
deaths, more than have died from Ebola, the team suggested.
Sources
WHO: Measles Mortality Reduction- a successful initiative
http://www.who.int/immunization/newsroom/measles/en/
Nathnac Travel Update March 2014
https://www.nathnac.org/pro/clinical_updates/measles_travel_010414.htm
European Centre for Disease Control: Surveillance 2013
http://www.ecdc.europa.eu/en/publications/Publications/measles-rubella-surveillance-oct-2013.pdf
Reduced vaccination and the risk of measles and other childhood infections post-Ebola. Science, 2015
http://www.sciencedaily.com/releases/2015/03/150312143030.htm
____________________________________________________________________________________________________________
Written by Dr Adrian Hyzler MBChB MBA
Senior Medical Officer, Healix International
© Healix International 2015.
All rights reserved.
th
Published 28 April, 2015
E: [email protected]
www.healix-international.com
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