@ NYTimes.com/Coronvirus Live Coverage, June 24

As the pandemic continues to grow around the world — new cases have risen more than 35 percent since the end of June — troubling resurgences have hit several places that were seen as models of how to respond to the virus.

An outbreak in Melbourne, Australia, has rattled officials after extensive testing and early lockdowns had limited outbreaks for months. Hong Kong — where schools, restaurants and malls were able to stay open — has announced new restrictions in the face of its largest outbreak since the beginning of the pandemic. And cases have surged in Tokyo, which has avoided a full lockdown and relied on aggressive contact tracing to contain flare-ups.

Spain’s reopening has stumbled in the month after it lifted a national lockdown. New cases have quadrupled, with high infection rates among young people, and forced hundreds of thousands of people to return to temporary lockdown. [....]

The scattered resurgences are not driving the pandemic. The biggest sources of new infections continue to be the United States, Brazil and India; the director general of the World Health Organization, Dr. Tedros Adhanom Ghebreyesus, noted this week that almost half of all cases worldwide came from just three countries.

But the quick turn for the worse in places that once seemed to have gained the upper hand shows the range of vulnerabilities the virus is able to exploit [....]