Since the rotavirus vaccine was introduced in 2007, diarrhea-related deaths among Mexican children under the age of 5 have been cut nearly in half. In aletter released Wednesday, August 24, in the New England Journal of Medicine, researchers provide evidence that confirms the vaccine’s role in this marked reduction.

The study compared the annual rate of childhood deaths caused by diarrhea 3 years after (2008-2010) and 3 years before (2003-2006) vaccination. They found that compared to the baseline, diarrhea mortality fell by 56% during rotavirus season and 46% annually among children under the age of 5. These findings translate into an annual reduction of approximately 880 deaths related to childhood diarrhea in Mexico. While some natural variation in infection rates could be responsible for the reduction, the authors write that since there was sustained reduction for 3 years after 2007, some of the drop in mortality rates is probably due to the vaccinations. These results counter concerns that the rotavirus is less effective beginning one year after vaccination.

“This new study highlights the importance of increasing access to affordable rotavirus vaccines in the developing world, where 85% of rotavirus deaths occur,” says Ciro de Quadros, Executive Vice-President of the Sabin Vaccine Institute.

Rotavirus is the most common cause of diarrheal hospitalizations and deaths among children worldwide, causing 2 million illnesses and over half a million deaths each year. The World Health Organization (WHO) recommends the use of rotavirus vaccines for all children worldwide to control the disease. The Sabin Vaccine Institute is currently working to facilitate the introduction of rotavirus vaccines in several targeted areas across the globe.

This story also appeared in the Los Angeles Times.