Media Advisory

Friday, September 6, 2019

WHAT:

The normal human intestinal microbiome is a thriving community of microorganisms, some of which may affect the human immune system. In a new article published this week in Cell, researchers have found that oral antibiotics, which can kill microorganisms in the gut, can alter the immune response of humans to influenza vaccination. The work was led by scientists from Stanford University and funded by the National Institute of Allergy and Infectious Diseases (NIAID), which is part of the National Institutes of Health.

The research team examined 33 healthy adult participants in their study. A group of 22 volunteers was studied during the 2014-2015 influenza season and the second group of 11 volunteers was studied during the 2015-2016 influenza season. The group of 22 volunteers had high pre-existing immunity to the influenza virus strains contained in the seasonal 2014-2015 influenza vaccine. The group of 11 volunteers was poorly immunized against the strains of the 2015-2016 seasonal influenza vaccine virus.

All participants in the study received a vaccine against seasonal flu. Half of the participants in each group also received a five-day broad-spectrum antibiotic treatment (composed of neomycin, vancomycin and metronidazole) orally before the vaccine was administered. By analyzing serum and blood serum samples collected at various times up to one year after vaccination, researchers tracked the immune response of influenza vaccine participants, as well as the diversity and abundance of organisms in their microbiomes. intestinal.

As expected, most participants who received antibiotics experienced a reduction in intestinal bacteria levels. In addition, among the 2015-2016 participants who had low immunity to seasonal influenza vaccine strains, antibiotic treatment impaired their immune response to one of the three strains. of the influenza virus of the vaccine, a specific H1N1 A / California virus. This probably indicates that if they were exposed to this H1N1 virus after vaccination, these participants would be less protected against infection with this strain than people who did not receive antibiotics, according to authors. This discovery corroborates the results of previous research on mice.

The researchers also found that people taking antibiotics had immune system changes that favored a pro-inflammatory state, similar to a condition seen in elderly people who were vaccinated against influenza. Researchers believe that this pro-inflammatory state is related to the process by which the microbiome regulates the metabolism of bile acid – with fewer microorganisms, this process is disrupted. Human microbiomes evolve naturally with age, and researchers suggest that further research on these pathways may explain why older people respond differently to influenza vaccination and why their immune systems are generally weaker.

ARTICLE:

T Hagan et al. A disturbance of the intestinal microbiome induced by antibiotics alters immunity to vaccines in humans. Cell DOI: 10.1016 / j.cell.2019.08.010 (2019).

WHO:

Alan Embry, Ph.D., Chief of the Division of Respiratory Diseases in the Division of Microbiology and Infectious Diseases at NIAID, is available to comment on this study.

CONTACT:

To schedule interviews, please contact Elizabeth Deatrick at (301) 402-1663, [email protected].

This press release describes basic research. Basic research increases our understanding of human behavior and biology, which is fundamental to advancing new and improved methods of disease prevention, diagnosis and treatment. Science is an unpredictable and progressive process – every breakthrough in research builds on past discoveries, often unexpectedly. Most clinical progress would not be possible without the knowledge of basic fundamental research.

NIAID conducts and supports research – at NIH, across the United States and around the world – to investigate the causes of infectious and immune-mediated diseases and to develop better ways to prevent, diagnose and treat these diseases. . NIAID press releases, fact sheets and other documents are available on the NIAID website.

About the National Institutes of Health (NIH):
The NIH, the country's medical research agency, has 27 institutes and centers and is part of the US Department of Health and Human Services. NIH is the lead federal agency that leads and supports basic, clinical and translational medical research. She studies causes, treatments and cures for common and rare diseases. For more information on NIH and its programs, visit www.nih.gov.

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