Conflict, inequality and skepticism limit global vaccine coverage
SCHNEYDER MENDOZA/getty images
The World Health Organization’s goal was lofty but achievable: eliminate measles from five of the world’s six regions by 2020. But recent outbreaks — even in places where elimination had been achieved — are making that goal a distant dream.
In the first four months of 2019, 179 countries reported 168,193 cases of measles. That’s almost 117,000 more cases reported during the same period last year. Actual numbers are probably much higher; the WHO estimates that only 1 in 10 cases are reported. With this uptick, none of the regions will meet the 2020 goal, says pediatrician Ann Lindstrand, vaccine lead for immunization systems at the WHO in Geneva.
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Even after a country attains elimination — defined as the absence of the continuous transmission of measles for a year or more — maintenance programs must be relentless, says Robert Linkins, a global measles expert at the U.S. Centers for Disease Control and Prevention in Atlanta. “Kids are born every day needing vaccines.… You have to keep up.”
The Americas is learning this lesson the hard way. In 2016, the region became the first to eliminate measles after its 35 countries immunized 95 percent or more of their populations (SN Online: 9/27/16). That’s the point at which herd immunity can keep safe those who aren’t immunized (often for health reasons or because they are too young). But across the region, vaccination rates have since dipped, and outbreaks in Brazil and Venezuela have cost the region its elimination status, according to a May 10 report in Science.
Reasons for recent failures vary across the world. Political instability, conflict and poverty can lead to shortages of vaccines (which must be refrigerated) and clinic closings. When civil war broke out in Côte d’Ivoire in late 2010, for example, the percentage of individuals getting vaccinated against measles plummeted, from an already low 70 percent in 2010 to 49 percent in 2011.
Some countries hardest hit by measles in the first three months of 2019 had very few cases the year before, according to provisional WHO data posted May 15, 2019.
Countries with the highest measles counts from January through March 2019
And vaccine hesitancy, cited by the WHO as one of the top 10 threats to global health in 2019, is a factor that needs to be addressed, in both high- and low-income countries, says Siddhartha Datta, vaccine-preventable disease and immunization program manager for the WHO’s European region.
The global rise in measles cases also suggests that health systems around the world are not working well. “Where you have cases, that’s where you have weaknesses of the system,” Lindstrand says. Many countries are facing stressors and challenges to vaccination. Here are snapshots from a few countries that are in the thick of it.
A dengue vaccine crisis dealt a blow to measles vaccination in the Philippines. Soon after the government approved a dengue vaccine in 2015, news emerged that it was making children sick. And there were reports that some children were dying from rare but serious reactions. The dengue vaccination program was suspended less than two years later. The episode led to “a huge upsurge in the Philippines of anti-vaxxers,” says Lotta Sylwander, a UNICEF representative who was based in the Philippines until March. Even before the debacle, other challenges to vaccination existed, including corrupt government officials, supply shortages and distributing the vaccine to the country’s thousands of far-flung islands, Sylwander says.
These issues plus growing vaccine hesitancy triggered a severe measles outbreak in late 2017 that still rages today. As of late March, the country had reported 23,000 cases this year and 333 deaths, mainly in young children.
Hit hard by political turmoil and vaccine hesitancy, Ukraine has seen a jump in measles cases in recent months. The first three months of 2019 witnessed more than 34,000 cases in Ukraine. The outbreak is no surprise, Datta says: In 2016, only 42 percent of children who needed the shot had received even a first dose of the vaccine. (A single dose protects about 95 percent of people who get the shot; a second dose ups protection to 99 percent.)
Several factors explain the low vaccination rates, says Sylwander, who is now based in Kiev, Ukraine’s capital. From 2009 to 2016, the country often ran out of vaccines, especially in the country’s conflict-ridden eastern region.
Ukrainians also have a history of vaccine skepticism. During the Soviet era, the government vaccinated everyone. But many children received faulty vaccines that had not been properly refrigerated. “Even though children were vaccinated, they became sick,” Sylwander says. Mistrust of government vaccination programs remains high (the recent U.S. measles outbreak in Washington state was focused in a tight-knit community of Ukrainian and Russian immigrants). Sylwander has even heard stories of medical staff in Ukraine falsely filling out children’s immunization cards to say they had administered a vaccine when they had not.
The country’s outbreak has spurred people to get vaccinated. And government programs over the last few years targeting vulnerable communities appear to be taking hold. The percentage of Ukrainian children who had received the measles vaccine jumped to 86 percent in 2017, according to WHO estimates. The challenge is reaching older children and teens who never got the shot.
On March 8, 2018, a 14-month-old Venezuelan boy arrived in Medellin, Colombia, and soon developed spots. Lab testing confirmed he had measles. Colombia hadn’t seen a case of measles since 2015. Public health officials went on high alert.
Amid a political and economic crisis that has thrown Venezuela’s health system into disarray, the country’s vaccination rates fell, Linkins says. With Venezuelans fleeing home by the thousands, Colombian officials knew the disease could cross into their country.
In 2017, the Colombian government began monitoring migrant health. Working closely with the CDC and the WHO, officials sent vaccinators to high-risk municipalities and set up vaccination stations at the Venezuela-Colombia border. From May to July 2018, more than 11,000 Venezuelans were vaccinated as they entered Colombia.
From March 2018 through April 2019, Colombia has reported only 302 cases of measles and no deaths. Colombian officials “were able to recognize people quickly and launch a charge,” Linkins says. “That’s a success story in my mind.”
In the last eight years, India has eliminated polio, maternal and neonatal tetanus and yaws, a tropical infection of the skin, bones and joints. Doing the same for measles will be challenging. With more than 12,400 cases reported in the first three months of this year, India has one of the highest measles caseloads in the world (only Madagascar, Ukraine and the Philippines are higher). Government officials have made a commitment to elimination, with some success.
In 2010, India introduced a second measles dose to its routine immunization schedule and targeted vaccination efforts toward its most vulnerable regions. “They’ve gone from success to success to success due to high political commitment,” Lindstrand says. From 2010 to 2013, deaths from measles in children under age 5 dropped 27 percent in targeted states compared with 11 percent drops in untargeted states, researchers reported in March in eLife. Those targeted efforts, the authors estimate, saved the lives of 41,000 to 56,000 children.
One of the poorest countries in Africa, Madagascar leads the world in measles cases, with more than 61,000 from January through March 2019 — a huge rise from just 27 total infections in the first three months of 2018. Less than 60 percent of the total population is vaccinated, and the country only requires a single dose of the vaccine.
The recent outbreak began in September 2018 and swept through the island. Between October 2018 and March 2019, more than 1,200 died.
In response, Madagascar began targeted campaigns, and vaccinated more than 7.2 million children. From October 22 to November 9, 2018, the campaign focused on children ages 9 months to 5 years in four regions of the capital, Antananarivo. Preliminary results suggest that 84 percent of those children had been vaccinated. A second campaign launched in January is aimed at children between 9 months and 9 years across 13 regions. Lindstrand says those efforts appear to be working, and the number of new cases is dropping. Madagascar will introduce a second dose later this year.
But the country will have to contend with a rainy season challenge. A study in the April 24 Vaccine found that babies who become old enough to get their first vaccine dose during the rainy season are more likely to miss the vaccination compared with other babies. Madagascar will have to address such seasonal issues as roads to clinics becoming impassable due to flooding and mud.
This story appears in the June 8, 2019 Science News with the headline, "Global hot spots: Almost everyone must get vaccinated to stop measles' spread."
K. Mensah et al. Seasonal gaps in measles vaccination coverage in Madagascar. Vaccine. Vol. 37, April 24, 2019, p. 2511. doi:10.1016/j.vaccine.2019.02.069.
B.K.C. Wong et al. The impact of measles immunization campaigns in India using a nationally representative sample of 27,000 child deaths. eLife. Published online March 5, 2019, doi:10.7554/eLife.43290.
A. Cunningham. Around the world, reported measles cases jumped 31 percent in 2017. Scioence News Online, November 30, 2018.
M. Rosen. Measles has been eliminated in the Americas, WHO says. Published online September 27, 2016.