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Can Probiotics Prevent Respiratory Tract Infections in Infants and Children?

/in ISAPP Science Blog /by KC

By Prof. Hania Szajewska MD PhD, Medical University of Warsaw, Poland

Imagine you are a primary care pediatrician practicing in an area where respiratory tract infections (RTIs) are particularly common during the winter months. Due to the seasonal surge in viral infections, you might find yourself seeing 20-30 children per day with upper respiratory tract infections (URTIs) at the peak of cold and flu season.

Children who attend daycare centers and kindergartens are especially vulnerable, experiencing up to four times more RTIs compared to those cared for at home (1). This is largely due to close contact and shared environments, making it easy for viruses to spread. About 95% of these infections are caused by five main viruses: rhinovirus, influenza virus, respiratory syncytial virus, coronavirus, and adenovirus. These viruses are primarily spread through airborne aerosols but surface contamination also plays a role. (1, 2)

Frequent RTIs in young children lead to missed daycare or school days, placing strain on families and increasing the need for healthcare visits. They may also lead to prescriptions for antibiotics, which can disrupt the gut microbiota and are associated with other health problems later in development. Severe cases of RTI may result in complications such as ear infections, pneumonia, or worsened asthma symptoms.

Preventing RTIs is essential for maintaining children’s health and reducing the burden on families and healthcare systems. This raises the question: Can probiotics help reduce RTIs in generally healthy young children attending daycare (3)?

The role of probiotics in preventing RTIs

Probiotics have gained attention for their potential to reduce RTIs, especially in children who are frequently exposed to infections in group settings like daycare and kindergartens. Initially the idea of ingesting probiotics into the digestive tract to prevent infections of the respiratory tract may seem counterintuitive. However, research has shown several potential mechanisms by which probiotics in the gut may help prevent RTIs:

  • Enhancing the immune system
  • strengthening the epithelial barrier
  • producing antimicrobial compounds
  • competing with harmful pathogens

While some mechanisms are strain-specific, others are observed across different types of probiotics.

Evidence from clinical trials

Comprehensive reviews and meta-analyses, such as a 2022 Cochrane review (4) have highlighted how various probiotics can lower the risk of RTIs. In children, 10 clinical trials showed that probiotics were more effective than placebo or no treatment in reducing acute URTIs. Key findings for the groups receiving probiotics include:

  • 28% reduction in the risk of at least one URTI event (relative risk 0.72, 95% CI 0.58 to 0.89; P = 0.003; 2512 participants)
  • 21% lower incidence rate of acute URTIs (rate ratio 0.79, 95% CI 0.65 to 0.96; 1868 participants)
  • 41% reduction in antibiotic use for treating URTIs (relative risk 0.59, 95% CI 0.43 to 0.83; 1315 participants)

Most trials involved administering probiotics through milk-based foods, such as yogurt, over a period of three months or longer, with consistent benefits seen across various age groups (4).

Acting on the evidence

While further research is needed to make definitive recommendations, there are several steps you can take, based on the current evidence, to reduce the risk of respiratory infections:

  • Use evidence-based probiotics: Although uncertainty remains about which strains are most effective, strains such as Lacticaseibacillus rhamnosus GG (formerly Lactobacillus rhamnosus) have been shown to reduce RTIs (5).
  • Support immune health with a fiber-rich diet: A diet rich in fiber and fermented foods, such as kefir, sauerkraut, and fermented dairy products, can promote gut health and immunity.
  • Focus on hygiene: Teach children proper hygiene practices, including frequent handwashing, proper sneezing and coughing etiquette, and regular sanitization of shared toys and surfaces, especially in group care settings.
  • Responsible antibiotic use: Limit the use of antibiotics to when they are absolutely necessary, because overuse can disrupt the gut microbiota and weaken the body’s immune system.

Conclusion

While we await more conclusive research, probiotics offer a promising, low-risk approach to supporting immune health and reducing the frequency and severity of respiratory infections in children. Incorporating evidence-based probiotics, maintaining a healthy diet, and practicing good hygiene can help minimize the risk of RTIs, particularly in communal environments such as daycare centers and kindergartens.

 

Should bacteriophages be considered as a member of the biotic family?

/in ISAPP Science Blog /by KC

By Prof. Colin Hill PhD DSc, University College Cork, Ireland

ISAPP has provided consensus definitions for a number of biotics that confer a health benefit on the host. These include prebiotics, probiotics, synbiotics and postbiotics, but here I want to put forward an argument that bacteriophages (phages) could qualify as a new member of the ‘biotic’ family.

 

Phages are bacterial viruses that infect and replicate within their bacterial victim before bursting the cell and releasing many new copies of the original virus. Phages can also integrate into the bacterial chromosome and co-exist with the living bacterium, but always with the threat that it can excise and initiate another replication-and-burst cycle. Phages are probably the most abundant biological entities on earth and are found wherever bacteria are present in the body. They are an important component of the microbiome of humans, plants and animals, and play a role in regulating bacterial community composition and function.

If phages are to fit neatly within the existing biotic family they would have to qualify as a biotic and also be shown to provide health benefits. The Oxford English Dictionary defines biotics as ‘of or relating to living organisms; caused by living organisms’. Bacteriophages (phages) are not considered as living organisms in themselves, but they easily fit within the biotic definition as they are completely dependent on living bacterial cells for their own propagation and as such certainly ‘relate to living organisms’.

There is also a significant body of evidence that some phages can confer health benefits on a host. Most of this evidence is based on using phage therapy to treat bacterial infections. This has been done in Russia for almost a century, and while the evidence may not always conform to western regulatory standards there is little doubt that phages can bring benefits such as limiting or clearing infections at various body sites. In a recent example, a randomised, controlled, blinded trial on burn wounds was conducted in Belgium and France with Pseudomonas aeruginosa as the target (1). A topically applied preparation consisting of low titres of a 12-phage cocktail was used. While the efficacy did not reach that of the standard-of-care sulfadiazine silver emulsion cream treatment, the phage treatments did lead to sustained reductions in bacterial burdens.

Phages can also be potentially used to modulate microbiomes to impact host health, as shown in a recent study I was involved in performed by Nate Ritz in the John Cryan lab where faecal virome transplants (FVT) changed the bacterial community and thus reduced the impact of stress-induced changes in behaviour and immune responses in mice (2). This paper was the topic of a recent ISAPP podcast for anyone interested in hearing more about that story. FVT has also been reported to work against Clostridioides difficile infections in humans in a small trial in Germany (3).

The term phagebiotic is perhaps the most fitting for this new type of biotic. I have always argued that we should not invent new terms for things that already have names, so why not just stick to bacteriophages or phages? It is because the term phagebiotic would be reserved for a very specific sub-category of phages. Just as all probiotics are microbes, but not all microbes are probiotics, I would suggest that phagebiotics should only be used to refer to specific phage preparations that have been shown to convincingly confer a health benefit in an appropriate properly controlled trial.

Mirroring the probiotics definition I would start with a suggested definition something like this; ‘phagebiotics are bacteriophages that, when administered in adequate amounts, confer a health benefit on the host’.

 

  1. Jault P., Leclerc T., Jennes S., Pirnay J.P., Que Y.A., Resch G., Rousseau A.F., Ravat F., Carsin H., Le F.R., et al. Efficacy and tolerability of a cocktail of bacteriophages to treat burn wounds infected by Pseudomonas aeruginosa (PhagoBurn): A randomised, controlled, double-blind phase 1/2 trial. Lancet Infect. Dis. 2019;19:35–45. doi: 10.1016/S1473-3099(18)30482-1
  2. Ritz, N.L., Draper, L.A., Bastiaanssen, T.F.S. et al. The gut virome is associated with stress-induced changes in behaviour and immune responses in mice. Nat Microbiol 9, 359–376 (2024). https://doi.org/10.1038/s41564-023-01564-y
  3. Ott, S. J., Waetzig, G. H., Rehman, A., Moltzau-Anderson, J., Bharti, R., Grasis, J. A., et al. (2017). Efficacy of sterile fecal filtrate transfer for treating patients with Clostridium difficile Gastroenterology 152, 799.e797–811.e797. doi: 10.1053/j.gastro.2016.11.010