Why are rich countries still monopolizing Covid-19 vaccines?

About half of the world’s population has received at least one dose of a Covid-19 vaccine. The more than 7 billion shots administered so far are a massive, record-breaking public health achievement.

But more than 50 countries have vaccinated less than 25 percent of their populations. Vaccines aren’t distributed equally: Rich countries have about twice the population of low-income countries, yet they have received about 50 times as many Covid-19 vaccine doses, according to an October report from the People’s Vaccine Alliance. The countries with the lowest incomes generally have the lowest Covid-19 vaccination rates.

This vaccination gap...