There was an interesting Bluesky post.
I agree. Drosten said in 2022 that someone who believes that they can train their immune system through an infection should, also believe that “by eating a steak they can train their digestion”. The immunity depth hypothesis was as nonsense as the hygiene hypothesis that immunity is depraved by modern hygiene.
In reality, post-pandemic seasons returned to historical volatility rather than showing any sustained amplification. RSV and influenza displayed timing shifts and one-off rebounds, but no long-term increase in total burden.
Nations with long and strict NPIs (like New Zealand, Taiwan) should have shown the largest rebound. By 2025 this clearly did not occur. Conversely, countries with minimal restrictions (Sweden, GB) still experienced unusual RSV and influenza patterns, demonstrating the hypothesis being wrong, but taking a huge death toll from their believers.
Memory B & T cells persist; mucosal training is complex but not any “use-it-or-lose-it“. The role of routine pathogen turnover was over- and homeostatic immune regulation underestimated.
