Between a hygiene rock and a hygienic hard place:Avoiding SARS-CoV-2 while needing environmental exposures for immunity

Suboptimal understanding of concepts related to hygiene by the general public, clinicians and researchers is a persistent problem in health and medicine. Although hygiene is necessary to slow or prevent deadly pandemics of infectious disease such as coronavirus disease 2019 (COVID-19), hygiene can have unwanted effects. In particular, some aspects of hygiene cause a loss of biodiversity from the human body, characterized by the almost complete removal of intestinal worms (helminths) and protists. Research spanning more than half a century documents that this loss of biodiversity results in an increased propensity for autoimmune disease, allergic disorders, probably neuropsychiatric problems and adverse reactions to infectious agents. The differences in immune function between communities with and communities without helminths have become so pronounced that the reduced lethality of severe acute respiratory syndrome coronavirus 2 in low-income countries compared to high-income countries was predicted early in the COVID-19 pandemic. This prediction, based on the maladaptive immune responses observed in many cases of COVID-19 in high-income countries, is now supported by emerging data from low-income countries. Herein, hygiene is subdivided into components involving personal choice versus components instituted by community wide systems such as sewage treatment facilities and water treatment plants. The different effects of personal hygiene and systems hygiene are described, and appropriate measures to alleviate the adverse effects of hygiene without losing the benefits of hygiene are discussed. Finally, text boxes are provided to function as stand-alone, public-domain handouts with the goal of informing the public about hygiene and suggesting solutions for biomedical researchers and policy makers. Lay Summary: Hygiene related to sewer systems and other technology can have adverse effects on immune function, and is distinct from personal hygiene practices such as hand washing and social distancing. Dealing with the drawbacks of hygiene must be undertaken without compromising the protection from infectious disease imposed by hygiene

Dietary Diversity and Dietary Patterns in School-Aged Children in Western Kenya: A Latent Class Analysis

Inadequate diet among children has both immediate and long-term negative health impacts, but little is known about dietary diversity and dietary patterns of school-aged children in rural Kenya. We assessed dietary diversity and identified dietary patterns in school-aged children in Western Kenya using a latent class approach. We collected dietary intake using a 24 h dietary recall among students in elementary schools in two rural villages (hereafter village A and B) in Western Kenya in 2013. The mean (SD) age was 11.6 (2.2) years in village A (n = 759) and 12.6 (2.2) years in village B (n = 1143). We evaluated dietary diversity using the 10-food-group-based women’s dietary diversity score (WDDS) and found a mean (SD) WDDS of 4.1 (1.4) in village A and 2.6 (0.9) in village B. We identified three distinct dietary patterns in each village using latent class analysis. In both villages, the most diverse pattern (28.5% in A and 57.8% in B) had high consumption of grains, white roots and tubers, and plantains; dairy; meat, poultry, and fish; and other vegetables. Despite variation for some children, dietary diversity was relatively low for children overall, supporting the need for additional resources to improve the overall diet of children in western Kenya