Please can you give a brief introduction to measles and who it affects?
Measles is a disease marked by fever, rash, and cold symptoms (red eyes, cough, runny nose) that results in a temporary suppression of the immune system and a drop in vitamin A levels.
Roughly one quarter of cases will have some sort of complication as a result of measles. These complications range from ear infections and diarrhoea to pneumonia and encephalitis. While in developed countries less than 1% of cases die, fatality rates can rise to 3-5% in some African and Asian countries. Complications are more likely in children less than 5 years of age (in up to 40% of cases) and in adults (in up to 30% of cases), and are more severe in those with malnutrition, HIV, or immune deficiencies. Before the first vaccine was licensed in 1963, measles killed more than 2 million children globally each year.
Measles is one of the most contagious diseases known to man and anyone exposed will develop measles, unless they are immune from prior disease or vaccination. Vaccination is typically done from 9-12 months of age and again in the second year of life, as two doses of vaccine are needed to ensure adequate protection. During outbreaks in areas with high vaccination coverage most of the cases have already been vaccinated – measles will find those few people still susceptible, even after one or two doses.
How has the number of measles deaths changed over the last decade?
Over the last decade (2000 – 2011, really 12 years) the annual global estimated number of measles deaths has dropped 71%, from 548,300 to 157,700 per year. All WHO Regions have shown declines, ranging from 90% in the Western Pacific Region to 48% in the South-East Asian Region. In the South-East Asian Region the decline was 36% in India and 70% for the other countries of the Region.
What do you think were the reasons behind this decrease?
The major factors have been the increase in coverage with the first dose of measles vaccine given through the routine immunization programme in countries throughout the world, plus giving a second dose in more and more countries.
The decline has been accelerated by the widespread implementation of measles mass vaccination campaigns in countries where children were not receiving a second vaccination through the routine immunization programme. The countries holding campaigns were also among the hardest hit by measles epidemics and deaths. Behind this success is the commitment of national governments to measles control and elimination and the hard work of healthcare workers worldwide.
Please can you tell us about the measles vaccine? How successful has this been in reducing measles deaths?
Measles vaccine has been very successful in reducing measles deaths and is the major factor in the decline. Receipt of 2 doses of measles vaccine delivered through routine services or in mass campaigns results in protection of >95% of children. When the proportion of the population immune to measles reaches a high enough level then the disease is effectively stopped and cases and deaths are very rare.
In which countries have people not received the measles vaccine and what are the reasons for this?
Over 20 million children are estimated to not receive the first dose of measles vaccine. Just over half of them are thought to be in five countries:
- the Democratic Republic of the Congo
These five countries also had large outbreaks of measles during 2011, highlighting the importance of a strong immunization system.
In most countries, including these five, measles outbreaks involved mostly unvaccinated persons, suggesting the main underlying cause was persistent gaps in immunization coverage. Even in European countries with large outbreaks, such as France, Spain and Italy, most cases were unvaccinated, suggesting gaps persist despite overall high measles vaccine coverage.
In addition, poor quality measles vaccination campaigns and delays in planned campaigns have resulted in low coverage, contributing to the increased number of measles-susceptible children and measles outbreaks.
Is the measles vaccine safe?
Measles vaccine has been well-studied and is safe. A mild rash and fever are the most common side effects, occurring in 5-10% of children, but more severe reactions are rare and no long-term problems have been found.
Of course, some people should not receive the vaccine, typically people with a history of severe allergic reactions to a previous measles vaccination (or to vaccine components), pregnant women, and people with severe immunodeficiencies. The vaccine does appear safe in otherwise healthy people with HIV infection.
How does the current progress in reducing measles deaths measure up to the Measles & Rubella Initiative’s goal to reduce measles deaths worldwide by 95% by 2015?
Measles deaths have declined by an estimated 71% between 2000 and 2011. While this decrease represents substantial progress, it falls short of the 2015 target of 95% since 2000.
Since 2008 progress has plateaued with increases in the number of reported cases for some regions and globally and a plateau in the estimated number of deaths due to measles.
Do you think it will be possible to eliminate measles completely?
Measles elimination in all parts of the world and resulting global eradication is definitely possible, both biologically and technically. The vaccine is very effective, the virus requires humans for transmission and the vaccine does not mutate into “wild” measles, so once eliminated we will be certain that the disease is really gone.
Also, most countries have proved capable of delivering the two doses needed, and relatively easy disease detection and confirmation can guide programme improvements more easily than other diseases. Currently, countries in five of the six WHO Regions have agreed to regional goals to eliminate measles; elimination has already been achieved in the Americas and is close to being achieved in the Western Pacific Region.
Would you like to make any further comments?
The combination of new resources from immunization partners and increased commitments by countries to fully implement measles control and elimination strategies will help resume progress toward achieving regional measles targets.
In April 2012, the Measles and Rubella Initiative (spearheaded by WHO, UNICEF, the US CDC, the American Red Cross, and the United Nations Foundation together with the GAVI Alliance, the LDS Church, Lions Clubs International, the Sabine Vaccine Institute, and many other partners) launched the 2012–2020 Global Measles and Rubella Strategic Plan to integrate rubella and measles elimination efforts, and provide strategies and guiding principles to resume progress toward regional measles elimination targets.
The Global Vaccine Action Plan for the 2011–2020 Decade of Vaccines provides strategic objectives and recommended activities for increasing ownership, accountability, and vaccination coverage, as well monitoring progress in part through achievement of regional measles elimination targets.
Significant new funding from the GAVI Alliance to fund measles and measles-rubella vaccination campaigns, in addition to its continued support for countries to add a second dose of measles vaccine to the routine immunization programme, provide a unique opportunity to boost population immunity to both measles and rubella.
Where can readers find more information?
About Dr. Robert Perry
Dr. Robert Perry is a medical officer working since 2011 in the Expanded Programme on Immunization at the World Health Organization and specializing on measles and rubella.
Originally trained as a paediatrician, he worked on a number of clinical research projects in Africa and Oceana before joining the US Centers for Disease Control and Prevention to work on the prevention and control of measles and later, in Senegal, on the prevention and control of malaria.