A vaccine delivered as nasal drops could potentially be effective for rotavirus, a study said.

Researchers from the Cummings School of Veterinary Medicine at Tufts University and Tufts University School of Medicine collaborated with researchers from Boston and Tulane Universities to test this approach on mice, which developed immunity against the rotavirus infection.

The study is published in the November issue of Clinical and Vaccine Immunology.

The nasal drops delivery has been tested successfully with tetanus and is being currently tested with diphtheria and pertussis.

"The new vaccine, in conjunction with an agent that enhances immunity, induced sufficient antibody formation against rotavirus to protect mice against infection when the mice were exposed to rotavirus three weeks after their third immunization," said John E. Herrmann, PhD, research professor in the infectious diseases division of the department of biomedical sciences at the Cummings School of Veterinary Medicine at Tufts University and the senior author of the published study.

Rotavirus causes severe diarrheal disease and is instrumental in death of over 500,000 children in developing nations. The nasal drops vaccine is favorable in developing countries, where vaccination is limited due to lack of refrigeration and trained manpower. The current vaccines have to be stored in refrigerators until it is administered.

"We created the rotavirus vaccine using a harmless bacterium called Bacillus subtilis (B. subtilis), which we can modify to display on its surface or in its cytoplasm proteins from infectious bacteria and viruses. When people are exposed to these proteins, they develop antibodies against them and therefore become immune to the bacteria and viruses," said the study's first author Sangun Lee, PhD, DVM, research associate at the Cummings School. "The B. subtilis bacteria are so harmless that they are part of the normal diet in several Asian countries.""The vaccine with the Bacillus bacteria is very inexpensive to produce in large quantities and, unlike most traditional vaccines, requires no special purification steps before use. As a result, the cost of vaccine production is unusually low," said Saul Tzipori, BVSc (DVM), DSc, PhD, Agnes Varis University Chair in Science and Society, distinguished professor of microbiology and infectious diseases, and director of the infectious diseases division of the department of biomedical sciences at the Cummings School.