Last week’s €750 billion ($877 billion) COVID-19 rescue fund marked a high point in the European Union’s plan to tackle the economic fallout of the virus. But a new flare-up in infections on the continent is a grim reminder of the more immediate epidemiological threat. While it’s not a second wave yet, it’s a serious test of government strategies intended to avoid one.

Cases are rising across the region at the highest pace since tough lockdown measures were lifted, although overall infections remain much lower than the outbreak’s April peak. In Spain, new daily cases hit almost 1,000 last week, driven by local spikes in areas such as Aragon and Catalonia, where nightclubs are now being closed and curfews applied on bars. In Belgium, an increase in infections has forced the government to roll out tougher social-distancing measures, such as limiting face-to-face interactions.

This shouldn’t come as a shock, given the epidemiological trade-off of easing lockdowns. People are naturally moving around more as stay-at-home curbs are rolled back, and this was always going to give the coronavirus more opportunities to mingle. Even if offices and public transport are still quiet, European streets are filled with shoppers, diners, and drinkers. Google mobility data indicate human traffic is almost back to pre-virus levels in regions like Paris, Madrid and Italy’s Lombardy.