The South African government has decided to pause its roll-out of the Astrazeneca-Oxford vaccine because of disappointing results of the vaccine’s effectiveness against the most common variant in the country in a trial of young people. And is there any good evidence from trials elsewhere that this vaccine reduces the chances of people spreading the coronavirus to others, as well as preventing severe illness and death? How do you test whether a vaccine prevents or reduces transmission of the coronavirus? Claudia’s regular guest epidemiologist Professor Matt Fox of Boston University discusses the issues.

As Donald Trump’s impeachment trial gets underway, reporter Alison van Diggelen looks at social science research on political polarisation in US society, and an experiment run by Stanford University to heal divisions.

Does a frequent intake of spicy food influence a person’s risk of developing cancers of the gut? Studies to date have been inconclusive but now a massive study following 500,000 people comes out of China, finding that spicy food is protective. Spicy food appears to lower the risk of getting cancer of the oesophagus and, to a lesser extent, the stomach as well.

Presenter: Claudia Hammond

(Picture: A doctor walks in the Respiratory & Meningeal Pathogens Research Unit at Chris Hani Baragwanath Hospital in Soweto, South Africa in July 2020. Photo credit: Luca Sola/AFP/Getty Images.)