Nurith Aizenman

How the chaotic system for distributing the world's vaccine supply is wreaking havoc in places that can least afford it.

While many African countries need more COVID-19 vaccines, others are struggling to administer the shots they have. Malawi and South Sudan have even had to throw out unused and expired doses.

One of the hottest areas of research right now: studies to determine how well current vaccines work against emerging coronavirus "variants of concern."

It's one of the hottest areas of COVID-19 research: How well do the various vaccines work against the variants? New findings are coming out daily. Here's what's known so far, and what's pending.

Mass shootings in Indianapolis, the Atlanta area and Boulder, Colo., cast a spotlight on this type of violence in the U.S., where the death rate is nearly 100 times higher than in the United Kingdom.

For this health expert based in Boston, the effort to get vaccines to his native South Africa was intensely personal.

South Africa is a case study of the inequities around the coronavirus vaccine. It has one of the world's worst outbreaks, fueled by a new variant. Yet officials are struggling to buy enough vaccines.

New results from a COVID-19 vaccine trial in South Africa suggest the vaccine that was developed by AstraZeneca may not be as effective against the variant found there.

Not everyone gets tested. A new model estimates how many infections are missed because of this and how many people are actively shedding the virus. The results lend urgency to the vaccine race.

New research shows how official figures understate the U.S. pandemic: On any given day the number of infected people who are actively contagious is ten times that day's tally of new reported cases.