Sunlight and Protection Against Influenza

NBER Working Paper No. 24340

Issued in February 2018, Revised in July 2020

NBER Program(s):Children, Environment and Energy Economics, Health Care, Health Economics, Public Economics



Recent medical literature suggests that vitamin D supplementation protects against acute respiratory tract infection. Humans exposed to sunlight produce vitamin D directly. This paper investigates how differences in sunlight, as measured over several years across states and during the same calendar week, affect influenza incidence. We find that sunlight strongly protects against getting influenza. This relationship is driven almost entirely by the severe H1N1 epidemic in fall 2009. A 10% increase in relative sunlight decreases the influenza index in September or October by 1.1 points on a 10-point scale. A second, complementary study employs a separate data set to study flu incidence in counties in New York State. The results are strongly in accord.

A non-technical summary of this paper is available in the 2018 number 2 issue of the NBER Bulletin on Aging and Health. You can sign up to receive the NBER Bulletin on Aging and Health by email.



Acknowledgments

Machine-readable bibliographic record - MARC, RIS, BibTeX

Document Object Identifier (DOI): 10.3386/w24340

Users who downloaded this paper also downloaded* these: