Scott Alexander examines theories for disease seasonality, proposing a dynamic model where seasonal factors entrain waning immunity cycles. Longer summary

Scott Alexander explores the seasonality of diseases, particularly focusing on flu and COVID-19. He discusses various theories for why diseases peak in winter, including cold temperatures, low humidity, indoor crowding, and vitamin D deficiency. He finds these explanations unsatisfactory and proposes that ultraviolet light might play a role. Scott then considers a dynamic model where disease immunity wanes over time, and seasonal factors entrain this cycle to create annual epidemics. He suggests that COVID-19 is currently in a 'half-seasonal' phase and may become fully seasonal once it has infected most of the population and exhausted easy mutations. Shorter summary

Scott Alexander critiques mass-produced medical recommendations, showing how they can oversimplify or misrepresent scientific evidence using vitamin D and niacin as examples. Longer summary

Scott Alexander critiques mass-produced medical recommendations, focusing on vitamin D and niacin supplements. He argues that popular sources like information graphics and websites often oversimplify or misrepresent the scientific evidence. Using vitamin D as an example, he shows how counting only positive studies can lead to misleading conclusions, as many larger studies and meta-analyses have found no benefit for cancer prevention or general health. He then discusses niacin, once thought beneficial but later found to be potentially harmful. Scott emphasizes the importance of considering all available evidence and being cautious about simplified recommendations. Shorter summary