  Hand hygiene is one of the key low-cost measures proposed by the World Health
Organization (WHO) to contain the spread of COVID-19. In a field study
conducted during the pandemic in June and July 2020 in Switzerland, we captured
the hand disinfection behavior of customers in five stores of a large retail
chain (n = 8,245). The study reveals considerable differences with respect to
gender and age: Women were 8.3 percentage points more likely to disinfect their
hands compared to men. With respect to age, we identified a steep increase
across age groups, with people age 60 years and older disinfecting their hands
significantly more often than younger adults (>+16.7 percentage points) and
youth (>+ 31.7 percentage points). A validation study conducted in December
2020 (n = 1,918) confirmed the gender and age differences at a later point in
the pandemic. In sum, the differences between gender and age groups are
substantial and should be considered in the design of protective measures to
ensure clean and safe hands.
