Oral vaccines may be unlikely to work for people in low-income countries because a gut disorder common in these nations damages the immune response in the intestines, a new study finds.
Researchers in Pittsburgh studied a gut disorder tied to poor sanitation by simulating the condition in mice, studying its impact on the immune system.
Among the mice with this disorder, 18 times fewer vaccine-specific immune system cells developed in the small intestine compared to healthy mice.
The findings suggest that oral vaccines for COVID-19 and other diseases may be ineffective in the very countries that would find these vaccines most logistically useful.
But with better sanitation and antibiotics, vaccine effectiveness may be improved.
Oral vaccines are currently in development for Covid, but they may not work well in low-income countries, a new study suggests
As the Indian 'Delta' variant wreaks havoc across the world, public health experts have called for Covid vaccines to be made more readily available outside of wealthy nations.
To aid in this effort, some scientists are working on oral vaccines.
The Israeli company Oravax Medical is starting clinical trials for one such vaccine this summer.
And in the U.S., biotechnology company Vaxart has applied for Food and Drug Administration approval of its own oral vaccine.
Oral vaccines are particularly useful in low-income countries that lack the trained healthcare workers and other resources required for mass needle-based vaccination campaigns.
But a new study demonstrates why this type of vaccine may not work as well for people living in the very countries that most need the technology.
Researchers at the University of Pittsburgh found that a gut disorder common in low-income countries impedes the immune system's ability to respond to oral vaccines.
For the study, published on Tuesday in the journal Immunity, the team focused on a condition called environmental enteric dysfunction (EED) - caused by malnutrition and contaminated food and water.
EED often occurs in regions with poor sanitation. Infection from contaminated food and water systems - combined with a poor diet - triggers gut
