For the final instalment of this series we are turning over the programme to you, our listeners. Over the past four months we’ve asked you to send us your questions, and you have obliged. But we haven’t always managed to reciprocate by answering them. In this episode, Tim Harford talks with a panel of experts who will try to answer as many questions as we can fit into a half an hour. Guests include Professor Beate Kampmann from the London School of Hygiene and Tropical Medicine, Professor Melinda Mills of Oxford University, and the GP Dr Helen Salisbury. Producers: Sandra Kanthal and Beth Sagar-Fenton Editor: Richard Vadon

Way back in the distant past that was last November, we rushed to produce the first episode of How To Vaccinate The World. Those were heady days. Pfizer and BioNTech seemed to be able to produce a stunningly effective vaccine using a brand new technology faster than we could learn how to pronounce BioNTech. Ever since then the vaccines, and the headlines about vaccines, have kept coming. So in the penultimate programme in the series, Tim Harford asks Rasmus Bech Hansen,CEO of Airfinity, Natasha Loder Health Policy Editor of the Economist and Dr Paul Offit Director of the Vaccine Education Center at the Children's Hospital of Philadelphia what we have learned in the past four months. Producers: Sandra Kanthal and Beth Sagar-Fenton Listener questions can be sent to: vaccine@bbc.co.uk

Tim Harford is an economist not an immunologist, so he's on solid ground with this week’s programme which is all about numbers. Some of them are small but significant: 7 reported cases of cerebral venous thrombosis in Germany. Others are huge: 400 million doses of Covid 19 vaccine administered around the world. Then there are the numbers that we’d love to know but don’t - about the effectiveness of a single dose, or whether we are getting closer to herd immunity. We find out what the numbers can tell us about Covid 19 vaccinations with this week's panel of guests: Professor Sheena Cruickshank, of the University of Manchester, Professor Susan Ellenberg, from the University of Pennsylvania and Professor Sir David Spiegelhalter of the University of Cambridge Producers: Sandra Kanthal and Beth Sagar-Fenton Listener questions can be sent to: vaccine@bbc.co.uk

More than 300 million doses of Covid 19 vaccines have been administered - that’s nearly three times the number of official Covid cases. But, the novelist William Gibson once said: the future is already here, it’s just not very evenly distributed and that’s certainly true for Covid 19 vaccines. Some countries are the haves, and others the have nots. So, where do we go from here if we are going to bring this pandemic to an end? That's the question Tim Harford asks this week's panel of guests: Gian Gandhi of UNICEF, Hannah Kuchler from the Financial Times and Prashant Yadav from Center for Global Development. Producers: Sandra Kanthal and Beth Sagar-Fenton Listener questions can be sent to: vaccine@bbc.co.uk

In the UK alone, more than 20 million people have had a first dose of a Covid 19 vaccine, and the government hopes to speed up the roll out by offering every adult a first dose by the end of July. But the word “offering” may be doing a lot of work in that sentence. Not everyone is taking up that offer - and there is a lot of talk about lower take-up rates of people in who are not both British and white - sometimes lumped together with the acronym BAME - Black, Asian and Minority Ethnic. In this week's How To Vaccinate The World, Tim Harford ask what is behind this trend, and what can be done to correct it with his guests Imam Qari Muhammad Asim, Chair, Mosques & Imams National Advisory Board, Dr Habib Naqvi - Director, NHS Race and Health Observatory and Dr Onyi Okonkwo, GP and clinical lead for BAME network at Birmingham and Solihull CCG, Producers: Sandra Kanthal and Beth Sagar- Fenton Listener questions can be sent to: vaccine@bbc.co.uk What Are Vaccines and Why Do They Work? Produced by Hip Hop Public Health

Monopoly is a good parallel for life in a pandemic because it deals out suffering at random, and it seems to go on forever. So people can be forgiven for asking: where’s our Get Out of Jail Free card? The answer might be vaccination passports. Or, it might not; the possibility of unintended consequences looms large. This week on How To vaccinate The World, Tim Harford will be asking if we need or want vaccine passports, and what problems they are trying to solve with his guests: Simon Calder, Travel Editor of The Independent, Professor Carsten Maple of the University of Warwick and Professor Melinda Mills of Oxford University. Producers: Sandra Kanthal and Beth Sagar-Fenton Listener questions can be sent to: vaccine@bbc.co.uk

Vaccines and Variants is a great title for a fun new geeky game but a very bad combination for public health. New variants of the virus which causes Covid 19 are turning up in countries all over the world. Can the vaccines we have keep up with them, or do years of booster jabs await us? Tim Harford answers these questions with this week's panel of guests: Professor Peter Hotez of the Baylor College of Medicine, Professor Emma Thomson of the University of Glasgow and Dr Adam Kucharski of the London School of Hygiene and Tropical Medicine. Producer: Sandra Kanthal Listener questions can be sent to: vaccine@bbc.co.uk

More than a 100 million people around the world have received a jab for Covid 19. But, we’re greedy - we want more. The virus is mutating, so vaccinations need to happen faster. And our vaccines are good, but will have to get better. Economists like to talk about incentives to get products to market faster, but will these tools that will work for the development of vaccines? This week Tim Harford puts this question to Professor Michael Kremer, winner of the Nobel Memorial Prize in Economics, Anna Mouser of the Wellcome Trust and Patrick Tippo of Biovac in South Africa. Producers: Sandra Kanthal and Josephine Casserly Listener Questions can be sent to: vaccine@bbc.co.uk

This week's panel of guests include President Biden’s Chief Medical Adviser, the long-serving director of the Infectious Disease Institute at the US National Institutes of Health, and a doctor who has been played on screen by Brad Pitt. All three of them are, of course, Dr Anthony Fauci. In this episode of How To Vaccinate The World Tim Harford talks with the world famous immunologist about the effectiveness and the roll out of vaccines in the US and around the world, what it’s been like to share a stage with Donald Trump in the depths of a pandemic, and answers questions from some of our loyal listeners. Producers: Sandra Kanthal and Josephine Casserly Listeners questions can be sent to vaccine@bbc.co.uk

No one’s safe until everyone is safe - it’s a phrase we are getting used to hearing. We are all going to look after each other and make sure everyone gets the vaccines they need. But this noble sentiment seems to be buckling under first contact with political reality, as rich countries jockey for position at the front of a very long queue. The elbows are out - just ask AstraZeneca. In this episode of How To Vaccinate the World, Tim Harford and a panel of expert guests, have a lively discussion about the dangers and perhaps the advantages of vaccine nationalism. Producers: Sandra Kanthal and Josephine Casserly Listeners questions can be emailed to vaccine@bbc.co.uk

The development of new vaccines for Covid 19 is a stunning scientific achievement. But now we some a cunning plans to get them out of their vials and into billions of arms around the world. Different strategies are being rolled out around the world, and like the virus itself, they are always evolving. In this episode of How To Vaccinate the World Tim Harford hears about vaccination strategies being rolled out in Indonesia and India and what the science tells us, and doesn't tell us, about who should be first in the queue. Listener questions for future episodes can be sent to vaccine@bbc.co.uk. Producers: Sandra Kanthal and Josephine Casserly

The vaccines are finally here, and countries around the world are running a race against time to get them into our arms as fast as possible. At the moment, Israel is leading the way, and the UK is currently forth in the world for vaccine doses administered. But, if the aim in Britain is to get 15 million people their first jab by mid February, we’re going to have to get more vaccines quickly. And that’s no mean feat because making vaccines is a complicated business, and delivering them isn’t easy either, even when you have the storks of Yeovil on your side. Tim Harford explains why on this edition of How To Vaccinate The World. Producers: Sandra Kanthal and Josephine Casserly

So, like buses, vaccine approvals, in the UK at least, seem to come in threes. First Pfizer/BioNtech, then Oxford/AstraZeneca and now Moderna have been given authorisation to be rolled out across the country. But, Britain, for the moment, is going it alone deciding to postpone second doses to up to 12 weeks. Is this the right thing to do? It’s a controversial question, and one Tim Harford asks a panel of guests: Professor Beate Kampmann, Professor Akiko Iwasaki and Professor Sir David Spiegelhalter on this week’s How To Vaccinate The World. Producers: Sandra Kanthal and Josephine Casserly For listener questions please email vaccine@bbc.co.uk

Epidemiologists don’t often hang out with rock stars, and not many of them can say they’ve played a part in eradicating a disease as deadly as smallpox. But Larry Brilliant isn’t your run of the mill public health official. He’s been warning about the dangers of a pandemic for years, and now that one is upon us, Tim Harford sat down to talk with him about how the world has handled the pandemic of 2020 and what we can hope for in 2021. Producer: Sandra Kanthal

As the co-founder of Microsoft, and one of the world’s richest men, Bill Gates has long been a poster child for geek power. But, through his Gates Foundation, he is also at the centre of the effort to end the pandemic of 2020. In this edition of How To Vaccinate The World, Tim Harford talks with Bill Gates about what he’s doing, what others are doing, and what needs to happen next if we are going to vaccinate a global population against Covid 19. Producer: Sandra Kanthal

What might the wonderful world of vaccines have in store for us in 2021? And what are the challenges that lie ahead in getting them to the billions of people who need them across the world? Tim Harford is joined this week by Dr Anna Blakney, Bioengineer at Imperial College London, Dr Nick Jackson from the Coalition for Epidemic Preparedness Innovations and Natasha Loder, Health Policy Editor at the Economist.

For a vaccine to work, people need to take it. But some are hesitant. On this week's How to Vaccinate the World, Tim Harford looks at why some people have concerns about taking a new coronavirus vaccine - and discussing how health providers, governments and the media should be responding. Tim is joined this week by GP Margaret McCartney, Marianna Spring, BBC Disinformation and Social Media Correspondent, and Professor Heidi Larson, Director of The Vaccine Confidence Project at London School of Hygiene and Tropical Medicine and author of Stuck: How Vaccine Rumours Start.

So, after much waiting and hoping, a Covid 19 vaccine has been approved for use in the UK. Now the roll out begins. But, it’s not easy moving around a vaccine that has to be stored at temperatures of an Antarctic winter, or organising two doses of the jab for the most vulnerable people around the country. On this week’s How To Vaccinate The World, Tim Harford talks with a group of experts about the complicated logistics of a vaccination programme being worked out in real time. Programme producers: Sandra Kanthal and Josephine Casserly

Tim Harford reports on what we know and don't know about the Oxford/Astra Zeneca Covid 19 vaccine, as well as answering questions from both the audience and our editor. On this week's panel of experts is Danny Altman, Professor of Immunology at Imperial College London, Jennifer Rogers, Head of Statistical Research and Consultancy at Phastar and Natasha Loder, Health and Policy Editor at the Economist.

It looks like we may finally be getting a coronavirus vaccine. But who’s “we”? Who is at the front of the queue, and who should be at the front of the queue? Should it be those with the greatest need or the highest bidder? In the second of the series, Tim Harford talks to GP Margaret McCartney, health economist Professor Philip Clarke and biological engineer Dr Anna Blakney. Contact us: vaccine@bbc.co.uk