@devisridhar When we have adequate supply then tiered pricing is used where the rich countries pay a lot more than middle income and low income pay the least which is funded by @gavi. When supply is limited rich countries have to not outbid the others so governments are key to this. #

@BillGates @gavi Looking back on 2020/21 (and given you warned of a respiratory pandemic for years before), what do you think is the biggest mistake most countries (with resources) made in responding?

@devisridhar @gavi A few countries like Australia moved fast to diagnose cases at scale and isolate people who were infected. They were able to limit deaths dramatically. Once the numbers get large in a country it is too late. So the first few months made a lot of difference.

@devisridhar @gavi Also some countries did a better job of reducing mobility, using masks and protecting the elderly. We weren't prepared - no practice in advance.#

@devisridhar @gavi Do you think the world will come together to get ready for the next one? I hope so but I am not sure.#

@BillGates @gavi I'm optimistic about the '100 day challenge'- the idea of sequencing a new genome to developing diagnostics, therapeutics and effective vaccines- and getting them out to people. But requires leadership, planning & foresight. Now is the window to prepare.#

@BillGates @gavi One major problem has been online misinformation on Facebook & other platforms around vaccines, masks and other interventions- how do we deal with this challenge? When expertise is neglected and conspiracy theories are spread as if they are truth?

@devisridhar @gavi Trusted authorities like @WHO and @CDCgov need more resources to see the pandemic early (surveillance) and to communicate better. Social media got behind on trying to get factual information out - there will be a lot of debate about how to do better on that...

@devisridhar @gavi @WHO @CDCgov People like you and I and Tony Fauci have been subject to a lot of misinformation. I didn't expect that. Some of it like me putting chips in arms doesn't make sense to me - why would I want to do that?#

@BillGates @gavi @WHO @CDCgov I'd make a joke but would cause a storm­čść. Turning to the Gates Foundation's mission, what do you see as the biggest challenges to development in poor countries now? Have we gone backwards on girls' education & the child survival revolution?

@devisridhar @gavi @WHO @CDCgov From 2000 to the start of the pandemic we made strong progress on health and other goals. The pandemic is a huge setback - including rich countries not focusing on the needs of developing countries as much. I hope we can reverse that.

@devisridhar @gavi @WHO @CDCgov I am optimistic about polio eradication - we are close. Malaria, HIV, Nutrition, will take a lot longer but better tools are coming. Education also needs innovation - it is behind where global health is particularly for girls.#

@BillGates @gavi @WHO @CDCgov So tough question: where do you think SARS-CoV-2 came from? What data do you want to see? And is this information important to preventing future spillovers & pandemics?