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One problem with the rotavirus vaccine-a preparation typically given by mouth to babies-is that it doesn't work as well in low-income countries, where the majority of rotavirus deaths happen. There were hints from earlier studies that the composition of recipients' microbiomes might be having an effect on vaccine effectiveness, which perhaps could explain why the rotavirus immunization isn't consistent. In a study published today (August 8) in Cell Host & Microbe, researchers have confirmed that the microbiome does indeed play a role in vaccine responses. In the double-blind, placebo-controlled study, men who received antibiotics before getting a rotavirus vaccine dose had a more robust immune response than those who didn't.

"It's an elegant study and raises a number of really interesting questions that people can now start to explore further," says Julie Bines, a pediatric gastroenterologist at the University of Melbourne in Australia who did not participate in the study. "The issue of why rotavirus vaccines don't work as well in developing or low-income countries as in high-income countries has been perplexing. If we can address [this issue] then we can ensure that those children can be better protected when they receive a rotavirus vaccine."

In 2017, Vanessa Harris, a physician and researcher at the University of Amsterdam in the Netherlands, and colleagues showed in two studies that the gut microbes of infants in both Pakistan and Ghana affected their responses to the rotavirus vaccine. "We saw that the bacterial microbiome was different in the responders and the nonresponders, so then that made us think that if you change the microbiome then maybe you can change the vaccine response," Harris tells The Scientist.

Investigating which bacterial taxa correlate with greater antibody levels and antigen shedding may make it possible to use those bacteria specifically to improve vaccine responses.

To test the idea that the microbiome might be one of the reasons that oral vaccines-specifically, rotavirus vaccines-are underperforming in these settings, Harris and colleagues recruited 66 healthy men who had been previously exposed to rotavirus and assigned them randomly to three groups. One group took broad-spectrum antibiotics for a week, the second a narrow-spectrum antibiotic, and the control group nothing. After the treatment, they all received the oral rotavirus vaccine.

The investigators did not see a difference in anti-rotavirus antibody levels 28 days after the vaccine as they had expected, possibly because the men had already been exposed to rotavirus. But one week after treatment, subjects who took the narrow-spectrum antibiotic showed a temporary boost in anti-rotavirus antibodies. The researchers also detected viral antigens in the stools of both groups that received antibiotics, but not in the control group, which suggests the vaccine virus was able to replicate within the intestine. And because antigen shedding correlates with vaccine protection in infants, the team viewed this as a positive outcome.

"The results are very modestly positive, with the shedding data being the most robust," Miren Iturriza-Gomara, a virologist at the University of Liverpool in the UK who did not participate in the study, writes in an email to The Scientist. Future research should aim to identify the bacterial taxa and species interacting with the vaccine, she adds, "as this could lead to the development [of] a prophylactic treatment which is fine-tuned to enhance vaccine responses and potentially gut health, rather than going down the route of fairly indiscriminate use of antibiotics, which will at the very best be a very blunt tool."

Harris acknowledges that there are caveats to the work. For one, the trial is in adults, not infants-the vaccine's target population. In the study the authors discuss the challenge this issue presents for directly translating this work to the clinic. But Harris says that investigating which bacterial taxa correlate with greater antibody levels and antigen shedding may make it possible to use those bacteria specifically to improve vaccine responses.

"Ultimately, the hope would be that you could then apply that to rotavirus vaccine candidates or existing rotavirus vaccines and improve their performance," she says. "But there are a lot of steps before you get there, so I think this is really a proof of principle that shows that it's worth the effort."
V.C. Harris et al., "Effect of antibiotic-mediated microbiome modulation on rotavirus vaccine immunogenicity: a human, randomized-control proof-of-concept trial," Cell Host & Microbe, doi:10.1016/j.chom.2018.07.005, 2018.

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Rotavirus Vaccine's Success Influenced By Gut Microbes

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One problem with the rotavirus vaccine-a preparation typically given by mouth to babies-is that it doesn't work as well in low-income countries, where the majority of rotavirus deaths happen. There were hints from earlier studies that the composition of recipients' microbiomes might be having an effect on vaccine effectiveness, which perhaps could explain why the rotavirus immunization isn't consistent.

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1. Estimated 600,00 deaths in children across the world in children
2. Responsible for 2 million people in the hospital each year
3. Nearly everyone will have rotavirus before turning 3 years old
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The Rotavirus Vaccine Saved 28,000 Children's Lives in 2016 - We Could Have Saved 83,000 More

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Umesh Parashar, MD and MBBS; Leads the CDC Division of Viral Diseases
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"Rotavirus Vaccines: Effectiveness, Safety, and Future Directions" This figure shows the estimated rotavirus mortality rates per country accross the world. Now there could be many reasons why one country has a higher mortality rate than another but it is a strong correlation to how effective and how widespread the vaccine is.

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Prevention: there are two vaccines available the rotateq and rotarix vaccines. (more)
Treatment: Over the counter oral rehydration medication
IV fluids
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Diagnosis: Rotavirus can be diagnosed through a physical exam but stool can be sent to a lab to confirm this diagnosis. (more)
Treatment: There is no direct treatment for rotavirus however, a few medicines can be used. Mainly it is recommended to drink lots of fluids due to the vomiting and diarrhea leading to dehydration. (more)

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Symptoms of rotavirus usually occur two days after exposure and include vomiting, diarrhea, loss of appetite, and dehydration. Dehydration can come with many symptoms like dry mouth, light headedness when standing up, and decreased urination. (more)

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3. What is the causative agent of rotavirus?

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3. What is the causative agent of rotavirus?

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Rotavirus, double stranded RNA with no envelope, made by combination of three layers of capsid proteins. (more)

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Rotavirus is a rod-shaped virus that causes swelling or inflammation in the intestines or stomach. This can lead to many complications including diarrhea, belly pain, vomiting, and fever.  This virus is normally observed in infants and young children but some adults can still be affected.  (more)

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Rotavirus - Causes, symptoms, transmission, treatment, prevention, photos