As 2020 drew to a close, a concerning development in the pandemic came out of Britain — a new variant of the coronavirus had been discovered that is significantly more transmissible. It has since been discovered in a number of countries, including the United States. The emergence of the new variant has added a new level of urgency to the rollout of vaccines in the U.S., a process that has been slow so far. Today, an exploration of two key issues in the fight against the pandemic. Guests: Carl Zimmer, a science writer and author of the “Matter” column for The New York Times; Abby Goodnough, a national health care correspondent for The Times. For an exclusive look at how the biggest stories on our show come together, subscribe to our newsletter. You can read the latest edition here. Background reading: The new variant of the coronavirus, discovered in December, appears to be more contagious than, and genetically distinct from, more established variants. Here is what we know about it. The first case of the variant in the U.S. was found in Colorado in December. Pfizer has said that its vaccine works against the key mutation. The distribution of the vaccine in the U.S. is taking longer than expected — holiday staffing and saving doses for nursing homes are contributing to delays. For more information on today’s episode, visit nytimes.com/thedaily