Impact of Gut Bacteria on Flu and Respiratory Infections
Understanding Flu Season and Its Symptoms
With the arrival of winter, the flu season also begins, leading to a notable increase in flu cases during colder months. Individuals infected with the influenza virus may experience a range of symptoms, including fever, cough, sore throat, muscle aches, and fatigue. As the flu is caused by a virus, antibiotics are ineffective; health professionals typically recommend rest and home care for symptom relief.
Complications from Influenza
While many recover from the flu within days or weeks, certain groups face a higher risk of severe complications. These complications can include pneumonia, ear or sinus infections, and inflammation of the heart or brain, as well as exacerbation of pre-existing health conditions.
Flu Vaccination and Its Efficacy
Each year, a new influenza vaccine, commonly known as the flu shot, is developed and made available at clinics and pharmacies during the fall and winter months. The formulation of the flu shot varies annually, and its effectiveness can differ among individuals. Research indicates that the vaccine’s efficacy is notably lower for older adults, with rates between 17-53 percent for those over 60, compared to 70-90 percent for younger populations. Although the flu shot is an effective preventive measure, it is not foolproof, prompting the exploration of additional methods to reduce flu risk.
The Role of Gut Bacteria in Immune Health
Recent studies have begun to investigate the connection between gut bacteria and overall health, particularly in older adults, who may not respond as well to the flu vaccine. Some evidence suggests that a healthy gut microbiome, characterized by beneficial bacteria, could support immune system function and potentially lower the risk of flu and other respiratory infections.
Research Study on Gut Microbiota and Flu Risk
To explore the relationship between gut bacteria profiles and flu risk, a study conducted in the Netherlands, published in The Lancet, collected stool samples from 397 participants aged 60 and above from October 1, 2014, to June 15, 2015. Participants completed questionnaires to report any influenza-like illness (ILI) symptoms during the flu season. Of the 397 participants, 213 reported experiencing ILI, while 184 did not.
Findings and Implications
The study revealed that individuals in the ILI group exhibited higher levels of the gut bacteria Ruminococcus torques. This particular species has been linked to decreased gut barrier function and elevated blood triglyceride levels. Furthermore, microbiota profiles were found to be altered during the symptomatic period of ILI. These findings suggest a potential association between flu-like illnesses and changes in gut bacteria composition, indicating that higher concentrations of certain bacteria may correlate with increased flu risk. However, additional research is necessary to validate these findings.
References
Buford, T.W. (2017). (Dis)Trust your gut: the gut microbiome in age-related inflammation, health, and disease. Microbiome 5(80).
Centers for Disease Control and Prevention (2020 August 31). U.S. Department of Health & Human Services. Retrieved 2021 January 11, from https://www.cdc.gov/flu/symptoms/symptoms.htm.
Deaver, J.A., Eum, S.Y., Toborek, M. (2018). Circadian disruption changes gut microbiome taxa and functional gene composition. Front. Microbiol. Doi: 10.3389/fmicb.2018.00737.
Fuentes, S., den Hartog, G., Nanlohy, N.M., et al. (2021). Associations of faecal microbiota with influenza-like illness in participants aged 60 years of older: an observational study. The Lancet 2(1), E13-E23. Doi: 10.1016/S2666-7568(20)30034-9.
Goodwin, K., Viboud, C., Simonsen, L. (2006). Antibody response to influenza vaccination in the elderly: a quantitative review. Vaccine 24: 1159-1169.
Rajilic-Stojanovic, M., de Vos, W.M. (2014). The first 1000 cultured species of the human gastrointestinal microbiota. FEMS Microbiology Reviews 38(5): 996-1047. Doi: 10.1111/1574-6976.12075.