Police secure an apartment complex used by Toennies meat company to house foreign workers from Eastern Europe during the coronavirus pandemic on June 20 in Verl, Germany. (Alexander Koerner/Getty Images)

BERLIN — In nations around the world that saw new coronavirus infections decline in recent weeks, spikes in confirmed case numbers have alarmed officials, and sent Australia, Germany, Portugal and South Korea, among other countries, scrambling to respond to resurgent outbreaks.

Within the countries in question, the new flare-ups are mostly rooted in identifiable regions, where officials launched or expanded aggressive containment efforts this week.