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MEASLES
1. Introduction
Measles virus is an enveloped virus, with single-stranded RNA, classified in the Paramyxoviridae
family. The virus has six structural proteins, including the haemagglutinin protein (H, responsible for
adsorption of virus to cells) and the fusion protein (F, responsible for fusion of virus and host cell
membranes, viral penetration and haemolysis of the host cell). Infection gives life-long immunity and
is caused by neutralizing antibodies against the H protein.
Measles virus is highly infectious. It is transmitted by respiratory droplets and by direct contact. From
about 4 days before appearance of the rash until 4 days after, patients are contagious. There exists
no asymptomatic carrier state.
Children under five are at risk, especially when they:

are malnourished (especially with vitamin A deficiency)

suffer from immune suppression (like HIV infection)

live in overcrowded conditions.
More than 20 million people are affected each year. WHO estimates that in 2008, 164 000 people
died of measles infection globally, what comes to nearly 450 deaths every day or 18 deaths every
hour.
Measles is a leading cause of death among young children even with a safe and cost-effective vaccine
on the market. Fatalities by measles infections reduced with 78% due to measles vaccination
between 2000 and 2008 worldwide.
2. Disease
By the end of an incubation period of 10 to 14 days, the patient develops prodromal symptoms like
high fever, cough, running nose and conjunctivitis before the typical measles rash occurs.
The rash appears after an extra 3 to 4 days, often with a fever of 39-40°C. The rash starts at the
hairline, then continues to the face and upper neck. During the next 3 days, the rash continues to
spread and reaches hands and feet. In the mouth, bluish-white spots (Koplik ‘s spots) are seen.
Patients normally improve by the third day after rash onset and are fully recovered 7 to 10 days after
onset of disease. People who recover from measles are immune for the rest of their lives.
Common complications of measles are middle ear infection, diarrhoea (and related dehydration),
severe respiratory infections like pneumonia (being the most common cause of death for measles)
and blindness (because of vitamin A deficiency). Post-infectious measles encephalitis (fever,
headache, vomiting, stiff neck, meningeal irritation, drowsiness, convulsions, coma) occurs in about
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1/1000 cases and subacute sclerosing pan encephalitis (SSPE, a slowly progressing infection of the
central nervous system by measles virus, going from mild mental weakening to seizures, blindness,
paralysis, coma and death, occurring 2 to 10 years after initial measles infection) in about 1/10 000100 000 cases.
In developing countries, case-fatality rates among children may reach 5-10%.
By ensuring good nutrition, sufficient fluid intake and treatment of dehydration with WHOrecommended oral rehydration solution, severe complications by measles infections can be avoided.
Antibiotics should be given to treat infections of ear and eye and pneumonia.
WHO currently advises to administer vitamin A to all acute measles cases. A high dose of vitamin A is
given immediately after diagnosis and repeated the next day for prevention of eye damage and
blindness. Studies show that Vitamin A supplements also decrease the number of deaths with 50%.
3. Vaccine
Most live-attenuated measles vaccines originate from the Edmonston strain (isolated by Enders and
Peebles in 1954). Strains derived from this strain, are the Schwarz, the Edmonston-Zagreb, the AIK-C
and the Moraten strains. There also exist non-Edmonston strains. All available vaccines protect
equally against wild type measles viruses, so we can talk of ”the measles vaccine”.
Measles vaccines are lyophilized and have to be reconstituted with a diluent just before use. Each
dose contains more than 1000 viral infective units of the vaccine strain. It can contain sorbitol (as
stabilizer) but does not contain thiomersal (as preservative).

Presentation, conservation and administration of the vaccine
Measles vaccines are available, either as monovalent or as measles-containing vaccine (MCV) in
combination with mumps, rubella, or varicella (or some combination of these).
It is recommended that the measles vaccine is stored between +2°C and +8°C, but it can be stored as
well between -70°C and -20°C for long-term storage. The diluents may not be frozen. The vaccine is
sensitive to sunlight, so it is kept in coloured glass vials. After reconstitution, the vaccine must be
stored in the dark at + 2°C to +8°C and used within 6 hours.
The vaccine is normally injected subcutaneously, but it is also effective when administered
intramuscularly.

Vaccination schedule
Vaccinating infants before or at the age of 6 months often fails to induce seroconversion. This can be
explained by the immaturity of the immune system and/or the presence of neutralizing maternal
antibodies.
Most countries use now a routine 2 dose schedule. Some of these countries organize supplementary
immunization activities (SIA’s) or catch-up campaigns. Others use a routine first dose plus regular
SIAs.
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In countries with ongoing transmission where the risk of measles mortality among infants remains
high, MCV1 should be administered at 9 months of age. MCV2 should be administered at 15-18
months of age.
In countries with low transmission, MCV1 may be administered at age of 12 months to take
advantage of the higher seroconversion rates achieved at this age. The optimal age for MCV2 is
based on programmatic considerations that achieve the highest coverage rate (e.g. with DTP booster
at 15-18 months or by school enrolment).
The minimum interval between MCV 1 and MCV 2 has to be one month.
In developing countries, mostly monovalent measles vaccine is given (no combinations with mumps,
rubella and varicella).

Vaccine efficacy and safety
Internationally available measles vaccines are safe, effective and may be used interchangeably within
immunization programs. The long-term presence of neutralizing antibodies (around 30 years) after
vaccination is well demonstrated. There is equal protection when measles vaccine is used alone or in
combined products: measles-rubella (MR), measles-mumps-rubella (MMR), measles-mumps-rubellavaricella (MMRV) or with other vaccines like DTP (administered at other injection site) and OPV.
Measles vaccine causes immunity in 89.6 % of the children aged 8-9 months (95% CI: 82-95%). In
order to prevent outbreaks, coverage has to be 100% with a single dose, which of course is not
realistic.
Of the 10% -15% remaining unprotected, 95% will develop immunity after a second dose. Therefore,
a second dose is advised. Programs that provide 2 doses of measles vaccine have been found to be
highly cost-effective, regardless of the method used to deliver the doses (in the routine healthcare or
with supplementary immunisation activities).
The measles vaccine is safe to use in HIV infected, asymptomatic children. Vaccination may even be
considered for those with symptomatic HIV infection if they are not severely immunosuppressed. In
areas where there is a high incidence of both HIV and measles infections, the first dose may be
offered as early as age 6 months. Two extra doses should be administered to these children.
Adverse reactions following measles vaccination are generally mild and temporary. Minor pain and
tenderness at the site of injection may occur within 24 hours; this is sometimes followed by fever
and local adenopathy.
Measles vaccine should not be given to pregnant women.
4. WHO recommendations
All infants and young children should receive measles vaccination through national immunization
programs. The vaccine may also be offered to previous non-vaccinated teenagers and adults at risk of
being exposed to measles virus (e.g. travellers to endemic areas and health care workers).
All children should be reached with 2 doses of measles vaccine. Population immunity needs to be 9395% in all districts to prevent measles outbreaks. Therefore, reaching and maintaining high
immunization coverage remains the basis of effective measles control.
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The aim of the fourth Millennium Development Goal (MDG 4) is to reduce the under-five mortality by
two-thirds between 1990 and 2015. Routine measles vaccination coverage was selected to measure
the progress of reaching the MDG 4. This because of the potential of measles vaccination to reduce
child mortality and given the fact that measles vaccination coverage can be considered as an
indicator of access to child health services.
Global coverage of the first dose of measles vaccination was 85% in 2010.
Measles has been eliminated in the AMRO region since 1994. All other regions, except SEARO, have
set an elimination goal to be achieved by 2020 or earlier.
5. References
- Centers for Disease Control and Prevention. Pertussis. Epidemiology and Prevention of VaccinePreventable Diseases. Atkinson W, Wolfe S, Hamborsky J, eds. 12th ed. Washington DC: Public
Health Foundation, 2011; 173-192.
-Cook GC and Zumla AI. Cutaneous Viral Diseases. In: Cook GC and Zumla AI, eds. Manson’s Tropical
diseases 22nd edition, Saunders, 2009; 835-838.
-Strebel PM, Papania MJ, Dayan GH and Halsey NA. Measles vaccine. In: Plotkin SA, Orenstein WA,
Offit PA, eds. Vaccines 5th edition, Philadelphia, Saunders , 2008; 353-398.
- WHO. Measles vaccine: WHO position paper. Weekly Epidemiological Record No 35, 2009, 84; 349360.
-WHO. Sixty-third World Health Assembly - Global eradication of measles. Report by the Secretariat –
25 March 2010.
- http://www.measlesinitiative.org/ [Accessed 18/10/2011].
-http://www.who.int/mediacentre/factsheets/fs286/en/index.html [Accessed 18/10/2011].
Network for Education and Support in Immunisation
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Last revision on 18/10/2011
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