Global Health Could Benefit.

• Position: VACCINE RISK INDEX

Vaccine hesitancy--delaying or refusing to vaccinate children even though vaccines are available--is a growing threat to global health. Vaccines kept diseases like measles at bay for decades; however, there has been an explosion of measles cases worldwide in recent years. Because it spreads easily, measles often is the first childhood Infectious disease to re-emerge when vaccination programs waver, making it a reliable indicator of declining vaccine coverage. Prior research has examined attitudes toward vaccination as a possible reason for waning coverage, but vaccine confidence may not fully explain these lapses.

To paint a more complete picture, a study published in the journal PLOS ONE digs into several factors in nations around the world to build a global vaccine risk index (VRI). Peter Hotez (director of Texas Children's Hospital Center for Vaccine Development), Brian Colwell (professor in the Texas A&M University School of Public Health), and Tasmi-ah Nuzhath (Doctor of Public Health student at A&M) examined data on 150 nations to explore economic and environmental factors that may explain variations in measles incidence and vaccine coverage worldwide.

The research team built VRI using data on measles incidence per 100,-000 people and vaccine coverage, confidence in the measles vaccine, percentage of people displaced by war and conflict, climate change effects, and education and income. They then analyzed the data and grouped the countries into six world regions: Africa, the Americas, the Eastern Mediterranean, Europe, Southeast Asia, and the Western Pacific. Using factor analysis, the researchers calculated a VRI score where higher values indicate higher risk of vaccine lapses and lower values show lower risk.

The analysis found countries with high VRI scores in every region, with...