There has been a pronounced increase in online shopping since the start of the COVID-19 pandemic. We study the effect of the pandemic on demand for online grocery shopping specifically, using municipality-level data from a Dutch online supermarket. We find that an additional hospital admission increased app traffic by 7.3 percent and sales per order by 0.31 percent. Local hospital admissions do not correlate with the variety of groceries ordered, but online search behavior does, suggesting that hoarding behavior is driven by the general perception and impact of the virus rather than local conditions. Local COVID-19 conditions also have different effects in urban versus non-urban municipalities, with local hospital admissions increasing app traffic in urban areas but lowering sales per order as compared to non-urban areas. It remains to be seen whether the demand for online grocery shopping will permanently increase as a result of the COVID-19 pandemic.