Measles outbreaks in the United States are provoked by a global push of the virus

In 2000, the Centers for Disease Control and Prevention declared that measles was "eliminated" from the United States. But as measles continues to spread and sometimes flourish in many parts of the world, the United States has not been able to stay safe from the disease.

This year, the United States has the highest number of measles cases in 25 years. As of this week, the CDC has registered 704 cases in 22 states.

The re-emergence of measles is linked to parents who have chosen not to vaccinate their children against this highly contagious disease.

But this is not the complete explanation. Dr. James Goodson, the CDC's lead researcher on measles, said outbreaks in the United States were triggered by a resurgence of measles worldwide.

The World Health Organization has identified more than 112,000 cases of measles in the first quarter of 2019. This represents an increase of over 300% over the same period in 2018. Dr. Tedros Adhanom Ghebreyesus, Executive Director of the World Health Organization WHO calls the "alarming increase in measles" and "global crisis".

Madagascar is plagued by a measles epidemic that has sickened 70,000 people and killed more than 1,000. Significant outbreaks also occur in Brazil, India, the Philippines, Ukraine and Venezuela. There have been small outbreaks in France, Greece, Israel and Georgia.

"When we see large measles outbreaks in countries that are common destinations for US travelers as we see this year," said Goodson. "That's when we often see the highest number of measles cases in the United States"

This is because of the nature of the virus. "Humans are the only reservoir of the measles virus," Goodson said. "The only way to contract measles is to get in touch with someone infected with measles."

Measles is one of the most contagious human diseases known to science. Before the introduction of a measles vaccine in the United States in the 1960s, the CDC estimated there were 3 to 4 million cases per year in the country.

Epidemiologists say that to stop the spread of the virus, 95% of people must be vaccinated or immunized against measles because they have already contracted the disease. In 2000, WHO launched a global campaign against measles with the ambitious goal of vaccinating 90% of children before their first birthday. The WHO at this stage did not even talk about "eradicating" measles; the goal was simply to "control" him.

The campaign reduced the estimated number of deaths from measles compared to half a million people worldwide each year in 2000, but the number of measles-related deaths began earlier this year.

"Overall, we have made great progress in reducing [measles] 80 percent of incidents since the year 2000, "said Goodson. But we are going through these periods of resurgence of measles. This happens and is related to people who are not vaccinated. "

Goodson says that there are three basic scenarios in the world in which measles eventually spreads in fertile soil.

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The first: countries that do not have health care infrastructure to conduct vaccination campaigns steadily. Depending on the formulation, the vaccine needs to be refrigerated – transported and stored at -58 degrees Fahrenheit to 5 F or -58 F to 46 F. Both temperature ranges can be a challenge in tropical countries where Electricity is irregular. Countries with the lowest vaccination rates also tend to rank among the least developed countries in the world: South Sudan, Chad, Haiti, Democratic Republic of Congo.

The second scenario fueling the spread of measles is civil war. This applies to countries like Syria and Venezuela that previously had strong immunization programs. These systems collapsed because of war or social collapse. And Goodson says it's not just about this particular country.

"This epidemic in Venezuela has spread throughout the Americas and infected countries like Brazil, Chile and Peru," he said. "I could go on and on, and most countries in the region have now been affected by this epidemic."

The third scenario feeding epidemics around the world is where parents choose not to vaccinate their children, while vaccines are widely available. These people do not believe that vaccines are safe, do not think that there are too many or do not trust the health system in general.

In 2017, the failed deployment of a dengue vaccine in the Philippines (which has proven to worsen dengue infections in people who had never previously experienced dengue fever) resulted in a decline vaccination rates for other diseases, including measles.

Dr. Robin Nandy, UNICEF's immunization officer, said that in some countries, like Ukraine, many of these scenarios were taking place simultaneously.

"Ukraine is a complex situation," said Nandy.

From March 2018 to February 2019, Ukraine recorded 72,408 cases of measles, the highest of any country in the world.

"They had problems with trust," he said of the high degree of skepticism about vaccines in Ukraine. "They have also experienced system outages, vaccine shortages that undermine the community's trust in health services."

In addition, clashes between the government and pro-Russian separatists have cut off parts of the country from others, disrupting many government services, including the distribution of vaccines.

In 2016, according to the WHO, only 42% of Ukrainian children were vaccinated against measles.

"This is not a cause or factor that causes low vaccination rates," Nandy said. "Every country is different, the Philippines and Ukraine are very, very different scenarios and there are very different reasons why children in these countries are not vaccinated."

Nandy says the measles virus is a "super-spreader". He can stay in the air in a room or on a plane for hours, waiting to find a new host. In case of exposure to the virus, 90% of unvaccinated people will be infected.

But Nandy points out that there is a super effective vaccine to fight this super-propagating virus. According to him, the challenge for health leaders around the world is to understand the complex social, economic and structural reasons that prevent the vaccine from reaching all those who need it.

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