In early September, officials in South Korea announced an ambitious plan to vaccinate 30 million people against the flu — 10 million more than last year, an increase aimed at keeping down rates of the flu while the country battled the coronavirus.

But as The Times reported last week, the internet soon got in the way. As the vaccine was distributed, a few logistical problems popped up, and South Koreans began circulating grave stories online — pictures of vaccine boxes that looked like they had been stored unsafely, reports of vaccine contaminated with mysterious white particles.