The rise of the Delta variant has prompted a thorny question: Do we need a booster dose of the vaccine for Covid-19? Vaccine makers think so, but regulators are yet to be convinced.

Principles are also at stake: Should richer countries be talking about administering extra doses when so many people around the world are yet to receive even a single shot?

Guest: Rebecca Robbins, a business reporter covering Covid-19 vaccines for The New York Times. 

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Background reading: 

• Although studies of a third dose are underway, experts agree that the vaccines are still working well. Here’s what to know about the potential booster dose.
• U.S. officials said that the decision to go ahead with a booster shot would depend partly on how many infections cause serious disease or hospitalization in vaccinated people.

For more information on today’s episode, visit nytimes.com/thedaily. Transcripts of each episode will be made available by the next workday. 

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