Administering rotavirus vaccine separately from oral polio vaccine could improve performance in low-income countries

January 3, 2020

By Kelly Jordan

Researchers at the Emory Rollins School of Public Health recently published an article in PLoS Medicine that examined the performance of the rotavirus vaccine among children in low-income countries. Julia Baker, PhD, MPH, postdoctoral fellow at Rollins, was lead author on the study.

Rotavirus is the leading cause of severe diarrheal disease and diarrheal-related deaths globally. In part, this is because rotavirus vaccines are less successful at triggering an effective immune response among children in lower-income settings, such as in South Asia and Africa, which is also where 90 percent of rotavirus deaths occur. 

“In this study, we sought to figure out why rotavirus vaccines don’t perform as well for children in lower-income countries, since these are the places where effective vaccines are needed most,” says Baker. “The scientific community has known for some time that rotavirus vaccines are about 90 percent effective in high-income countries and 50 percent effective in low-income countries. But no individual study could explain why.”

The researchers analyzed data on over 7,000 infants from 33 countries that participated in 22 of GSK’s Rotarix® vaccine trials to determine which factors were related to the vaccine’s lower performance in low-income countries.

Results showed that children who received the oral poliovirus vaccine at the same time as the rotavirus vaccine had a poorer immune response than those who received the rotavirus vaccine on its own. The Rotarix® vaccine is given in a two-dose series. Some smaller previous studies suggested that after a second dose of rotavirus vaccine, children who didn’t get good protection from their first dose could catch up. The authors found that oral poliovirus vaccine’s interference persists even after a second dose of rotavirus vaccine. 

“These findings suggest a practical way that the rotavirus vaccine performance might be improved: by administering it without oral poliovirus vaccine. This is already how the vaccine is given in high-income settings. And, as part of the effort to eradicate polio, the oral poliovirus vaccine is being withdrawn globally [and replaced with inactivated polio vaccine delivered through a series of shots; the only way the polio vaccine has been administered in the United States since 2000]. That withdrawal may result in improved rotavirus vaccine performance, especially in low-income settings where deaths from rotavirus infection are greatest,” says Baker.

Benjamin A. Lopman, Michael J. Haber, and Juan Leon, also from Rollins, were also authors on the paper.