Annales 80.2 - Prevention of allergies in the post pandemic era
The COVID-19 pandemic has drastically changed human activities across the world in efforts to minimize risks relating to the disease, especially when it came to social distancing and practices related to disinfection. This may have affected human immune system and the environmental microbiota interactions, thus affecting how allergies develop. In this issue, we review the impacts of the COVID-19 infections on those with allergies, how pandemic measures might have changed the exposome and its effects on the immune system of those born in the time of the pandemic, how neonates may develop a healthy intestinal microbiome that may promote a balanced immune system, and how maternal diet and early infant feeding practice may influence the subsequent development of food allergy.
The COVID-19 pandemic has resulted in unprecedented disruption of human activities across the world. In order to minimise the morbidity and mortality related to this infection, countries across the world implemented drastic social distancing measures and restrictions including border closure, school closure, work from home arrangement and prohibition of mass gatherings.1 It seemed that the world had come to a complete stop. On a personal level, the use of mask, frequent hand washing and the widespread use of disinfecting agents result in marked reduction of circulation of a variety of microbes, especially respiratory viruses. With the development of vaccines, effective medications along and herd immunity due to vaccination or natural infection, the WHO declared on 5 May 2023 that COVID-19 was no longer a global public health emergency. In the past three decades, there has been significant advance in our understanding of the importance of health depending on the
interaction of the human immune system and the environmental microbiota.2 3 The pandemic measures may have changed such interactions affecting the development of allergies. In this issue, we have researchers from around the world to discuss our recent understanding in the prevention of allergy and the how the pandemic may shape our primary preventive strategies. In the article How does the pandemic shape the future of allergies?, Papadopoulos and Miligkos reviewed the impact of COVID-19 infections on individuals with allergies and how the pandemic measures might have changed the exposome which may have long lasting effects on the immune system of those born during the pandemic. West summarised in her article the current knowledge of how newborns may acquire a ‘healthy’ intestinal microbiome which induces a balanced immune system such that the individual will have the ability to fight pathogens but will not mount excessive response to innocuous allergens. Many factors such as mode of delivery, use of antibiotics in early life and home environment can all affect the gastrointestinal microbiome, and they all play a role in the subsequent development of allergies. Following the first wave of increase in asthma and allergic rhinitis, food allergy has become the second wave of the epidemic of allergy showing a rapid increase over the past two decades.4
Venter and Heine described in their articles the current evidence regarding how factors in the maternal diet and early infant feeding practice may influence the subsequent development of food allergy. Maternal exposure to a diverse diet and early exposure to a variety of food allergens in early infancy are not associated with
tolerance. The four articles in this issue provide comprehensive updates of our current understanding of how feeding practice and environmental exposure may modulate the early immune system. Such modulation is likely to be mediated by interactions between the host immune system and the environmental and gastrointestinal microbiome. The clear understanding of such interactions will pave the way for the development of effective allergy preventive strategies.
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Funding. The author has not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests. None declared.
Patient consent for publication Not applicable.
Ethics approval Not applicable.
Provenance and peer review Not commissioned;
internally peer reviewed.
REFERENCES
1 - Sun KS, Lau TSM, Yeoh EK, et al. Effectiveness of different types and levels of social distancing measures: a scoping review of global evidence from earlier stage of COVID-19 pandemic. BMJ Open 2022;12:e053938.
2 - Huang YJ, Porsche C, Kozik AJ, et al. Microbiome-immune interactions in allergy and asthma. J Allergy Clin Immunol Pract 2022;10:2244–51.
3 - Rey-Mariño A, Francino MP. Gut microbiota, and allergy development in infants. Nutrients 2022;14:4316.
4 - Prescott S, Allen KJ. Food allergy: riding the second wave of the allergy epidemic. Pediatr Allergy Immunol 2011;22:155–60.
