Your Immune System Is Not a Muscle

Vaccines, Viruses, and Autoimmunity

• Several comments discuss viral infections as triggers for autoimmunity via mechanisms like molecular mimicry, and note some vaccines also have rare autoimmune risks (e.g., GBS).
• Disagreement over how well COVID vaccine risks were communicated and who counts as an “expert”; some argue real experts rarely talk to the public, others blame toxic public debate.
• One commenter stresses mechanistic differences between viral infection and most vaccines (e.g., viral replication vs. non‑replicating antigens).

Rising Allergies and Autoimmune Disease

• Many share anecdotes of new adult-onset allergies, eczema, GI issues, and food sensitivities.
• Some attribute this mainly to lifestyle: chronic overnutrition, sedentary behavior, ultra‑processed food, high sugar, and disrupted satiety signals.
• Others point to environmental exposures (preservatives, pesticides, PFAS, microplastics), though this is contested and sometimes labeled a distraction from overconsumption.
• Vitamin D deficiency is highlighted with multiple study references suggesting substantial reductions in MS, T1D, and autoimmune incidence with higher vitamin D or supplementation.

Microbiome, Parasites, and “Old Friends”

• Several cite studies on helminths and gut parasites alleviating IBS or allergies, but others with chronic conditions say helminths did little and are wary of overhyping them.
• Debate over the “old friends” vs. “hygiene” framing: some emphasize immune calibration by early microbial exposure; others note immune system training is highly timing‑ and context‑dependent and that many “friendly” microbes can be pathogenic in the wrong host.

Antibiotics, Gut Health, and Hygiene

• H. pylori is described as a common, under‑checked cause of GI issues that is usually curable with a 14‑day antibiotic course; concerns raised about long‑term microbiome disruption.
• Mixed views on probiotics post‑antibiotics; evidence seen as inconclusive.
• Handwashing habits and nasal rinsing come up as low‑tech ways to reduce infections, with some regional variation in norms.

Immune System Models and Tissue Repair

• Discussion of whether “immune system as muscle” is misleading; alternatives proposed include antifragility and “Skynet”–style dangerous overreactions.
• Several push back on claims that cartilage or ligaments “don’t grow back,” citing newer work suggesting partial regeneration and non‑surgical ACL healing in some cases.