Full Moons and Helicopter Emergency Medical Services (HEMS) Activations in The United States

Published:November 05, 2022DOI:


      A long-standing misconception in emergency medicine is that full moons are associated with increased patient volume. Although there has been ample work debunking this belief, virtually no scholarship has tackled this question from the perspective of helicopter emergency medical services (HEMS). We examined a national-level database populated by EMS agencies throughout the United States (NEMSIS) and compared three-day periods containing every full moon in 2019 with control three-day periods one week immediately before and one week immediately after a given full moon. The daily average number of HEMS activations was then compared. A significant increase was defined as full moon periods having at least 20% more HEMS activations than the control periods before and after the full moon. In 2019, full moons had a daily average of 496 HEMS activations, and non-full moon periods had a daily average of 510 HEMS activations. Furthermore, no months saw full moons having a significant increase in HEMS activations. Our data provides important support for the idea that full moons do not translate into increased HEMS activations.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Air Medical Journal
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Danzl DF.
        The Journal of emergency medicine. 1987; 5: 91-95
        • Coates W
        • Jehle D
        • Cottington E.
        Trauma and the full moon: a waning theory.
        Annals of emergency medicine. 1989; 18: 763-765
        • Thompson DA
        • Adams SL.
        The full moon and ED patient volumes: unearthing a myth.
        The American journal of emergency medicine. 1996; 14: 161-164
        • Shekhar AC
        • Blumen IJ
        • Mann NC
        • Mader T.
        Full moons are not associated with increases in emergency medical services (EMS) activations (911 calls) in the United States.
        The American Journal of Emergency Medicine. 2022; (Jul 20)
        • Ruskin KJ.
        Helicopter air ambulance services.
        Current Opinion in Anesthesiology. 2019; 32: 252-256
        • Lerner EB
        • Newgard CD
        • Mann NC.
        Effect of the coronavirus disease 2019 (COVID-19) pandemic on the US emergency medical services system: a preliminary report.
        Academic Emergency Medicine. 2020; 27: 693-699
        • Shekhar AC
        • Effiong A
        • Ruskin KJ
        • Blumen I
        • Mann NC
        • Narula J.
        COVID-19 and the prehospital incidence of acute cardiovascular events (from the Nationwide US EMS).
        American Journal of Cardiology. 2020; 134: 152-153