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MeaslesEvery minute a child dies of measles. Even though a safe and effective vaccine exists, outbreaks occur in many parts of the world because routine immunization programs are not in place or efficient. In many places Doctors Without Borders/Médecins Sans Frontières (MSF) teams are confronted with outbreaks and have to organize emergency immunization campaigns, which represent a complex logistical challenge.
Measles still kills in the 21st century According to the World Health Organization (WHO), out of the 30 million children affected by measles every year, about half a million die. Most of those deaths occur in Africa and Asia. This contrasts sharply with the Western world where measles cases have become extremely rare thanks to universal routine immunization. This leads many people to forget that measles is a major killer. Measles is highly contagious. Symptoms like runny nose, cough, eye infection, and rash appear about 10 to 14 days after exposure to the virus. There are different levels of severity, and deaths following measles infection are usually due to measles-related complications like diarrhea, dehydration, and respiratory infections (pneumonia, croup). Those deaths can occur weeks after the acute disease and are not always attributed to measles. Mortality can reach 5 percent to 20 percent of measles cases. Initial health condition, access to health care, and proper treatment provision are factors influencing mortality. Malnutrition is often a secondary effect of measles because the disease consumes a lot of a child's energy. This can push children into a deadly vicious cycle of infection and malnutrition. "In a recent measles outbreak in Nigeria [in 2005], about half the children treated by MSF suffered from severe acute malnutrition making them at immediate risk of dying if not treated immediately," says Christine Dubray, from Epicentre, an epidemiology institute collaborating with MSF. It is mainly in these type contexts that MSF teams have to undertake emergency vaccination campaigns.
Vaccination campaign The decision to start a campaign is taken when the number of cases is high compared to the same period of previous non-epidemic years. As that information is often not available, it is very difficult to determine whether or not there is an actual outbreak. When an outbreak is suspected or confirmed, MSF then discusses with the local authorities to see if, when, and how the campaign will take place, bearing in mind that sooner is always better. First of all, the teams have to identify the target population. Commonly in these situations, the most affected group is children under the age of five who have not been vaccinated through routine immunization or previous campaigns. It is also in this group that the measles mortality is the highest. Older children can also represent a reservoir for the virus, and therefore the target population is usually all children between 6 months and 15 years. Children under six months do not have to be vaccinated as they are still protected by their mother's antibodies.
Getting people to vaccination sites Before starting the campaign itself, it is crucial to convince parents of the importance of vaccinating their children. Awareness strategies can vary according to different settings but most typical ones include posters and radio spots as well as talks in churches and schools. Sonia Peyrassol, of the MSF Emergency Unit, stresses that "the key to a vaccination campaign's success is the sensitization component. The act of vaccinating is quite simple, but along with logistics, one of the main challenges is to make sure people come to our sites." The next step is to set up vaccination posts in convenient places to make sure parents can easily bring their children. Posts are usually set up where people gather like schools, markets, churches, or close to more remote isolated communities. Infrastructure can be very simple–a table and fences to channel the influx of people.
In MSF interventions, these positions are filled by national staff and are crucial to the success of a measles vaccination campaign. This is why the MSF coordination team has to make sure that all people involved are properly trained. Once started, the process is usually very quick and there is no space for mistakes. A typical campaign lasts between two and three weeks and can cover up to several hundred thousand children. A huge and complex logistical undertaking Even though administering the vaccine itself is quite straightforward, the logistical work behind it is extremely complex and challenging. This includes daily transport of the different teams and coordinators to the sites. It also includes the material for every site like syringes, vaccination cards, tally sheets and of course, the vaccine itself.
The vaccine needs to remain refrigerated and therefore requires the use of a cold chain from the place of production to the vaccination site (see box below). This can prove to be a tough challenge, especially in places with no electricity. Usually, generator-powered refrigerators are installed not only to keep the vaccine, but also to produce huge amounts of ice packs. They allow teams to carry the vaccine day after day to every single site in carrier boxes. During and after the campaign, dealing with the mountains of used syringes, needles and capsules is also very important. There are very strict and specific ways to isolate these items in specific waste boxes, then burn some and encapsulate others in concrete before burying them. If not dealt with properly, wastes represent a toxic hazard for the local community. On top of the vaccination effort, one has to keep in mind that people already infected with measles must be treated. During an epidemic, community health workers are usually well aware of the possibility of being confronted with measles cases. After isolating patients, all systematically receive treatment for lack of vitamin A, ocular complications, stomatitis (viral mouth infection), dehydration, and protein deficiencies. Some specific treatment for fever, diarrhea, malnutrition, and sepsis may have to be provided to some patients.
Sharing lessons learned There have been questions raised about the effectiveness of emergency vaccination campaigns in open settings–as opposed to camps, schools, or isolated areas–to respond to measles outbreaks. There is indeed skepticism in the scientific community about the value of vaccinating in the middle of outbreaks. But Christine Dubray insists that, "Analyses of data collected during outbreaks in Chad, Niger and Congo suggest that vaccination activities during measles outbreaks may have an impact in reducing the numbers of deaths and cases. As these outbreaks last several weeks, there is time to intervene before the peak, and to curb the spread of the disease." Even if progress has been very rapid in the last few years and measles-related deaths have decreased dramatically, there are still far too many unnecessary deaths. They could easily be prevented if routine vaccination and surveillance were more widely available. |
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MSF Report November 2006 — Exploring the time to intervene with a reactive mass vaccination campaign in measles epidemics
