President Biden is asking world leaders to pledge to vaccinate 70% of the global population by September next year. But research shows rich countries are still holding surpluses of vaccines, many of which could soon be thrown out. Boarding a plane to Iran this summer, Bahar was excited to see her father for the first time in four years. She had no idea coronavirus was about to rip through the country - and her family - in a deadly second wave. First it was a friend of the family, who was preparing for her son's wedding when she got sick. She died soon after. Then it was her father's uncle, then an elderly aunt. Bahar worried desperately about her grandmother who had only had one vaccine dose and was still waiting for her second. Bahar is 20 and lives in the US where she got vaccinated in April. Though she knew she was somewhat protected, she spent the final days of her trip cloistered in her father's house worried about who the virus would attack next. Few members of her family have been vaccinated in a country where supplies are low. Soon after she returned to the US, she found out her father was sick. She was far away and paralysed with fear. "It's like survivor's guilt," she says. "I left Iran totally fine, completely healthy just because I had two shots of the Pfizer vaccine." Her father recovered but many older relatives did not. "I felt pretty guilty knowing that." This imbalance of the vaccine supply makes for stark statistics. Just over half of the world has yet to receive even one dose of a Covid-19 vaccine. According to Human Rights Watch, 75% of Covid vaccines have gone to 10 countries. The Economist Intelligence Unit have calculated that half of all of the vaccines made so far have gone to 15% of the world's population, the world's richest countries administering 100 times as many shots as the poorest. In June, members of the G7 - Canada, France, Germany, Italy, Japan, the United Kingdom and the United States - pledged to donate one billion doses to poor countries over the next year. "I smiled when I saw that," says Agathe Demarais, lead author of a recent report on global vaccines supply at the Economist Intelligence Unit and a former diplomat. "I used to see this a lot. You know it's never going to happen." The UK promised 100m of that pledge, so far it has donated just under nine million. President Biden pledged 580m of which the US has delivered 140m so far. And the EU bloc promised 250m doses by the end of the year - it has sent about 8% of those. Like many middle-income countries, Iran bought vaccines from Covax, the global scheme supported by the WHO to get doses where they're needed most. Covax purchases and then sells vaccines at low-cost to middle income countries and donates to poor countries.