The Hong Kong protests were among the first to feel the chilling effects of the virus.

The protests began in June, to oppose a bill that would have allowed extraditions from Hong Kong to mainland China. They soon spiraled into some of the largest in Hong Kong’s history, with millions marching to denounce police brutality and Beijing’s growing influence over the city.

But in January, as news spread of a mysterious virus in China, many grew leery of crowds. The freeze became official in March, when officials banned public gatherings of more than four people. Since then, police have arrested attendees of sporadic protests.

“What can we do?” said Max Chung, an activist who was arrested last July after organizing a protest of hundreds of thousands of people. “When the time is right, of course I will organize another protest. But it is impossible right now.”

A combination of top-down mandates and grass-roots hesitation has paralyzed protests elsewhere.

In Algeria, twice-weekly street protests that roiled the country for more than a year dried up in March, as protesters agreed to focus on fighting the virus — a decision solidified by the country’s new ban on public demonstrations.

As awareness of the virus spread in Beirut, protesters at first donned masks to chant against corruption and religious sectarianism. But they dispersed in the face of a nationwide lockdown, and last month, security forces dismantled encampments where protesters had slept, held teach-ins and danced to revolutionary anthems.

Attempts to defy the restrictions have met backlash from not only the government but also allies. After opponents of an anti-Muslim law in India said they would continue protesting during lockdown, even supporters criticized them as reckless.