Millions in developing nations from Latin America to the Middle East have been left anxiously waiting for more doses of the Sputnik V coronavirus vaccine as Russia struggles to meet global orders. Moscow aggressively marketed Sputnik after wealthy nations kept supplies of Western-developed vaccines for themselves, but unfulfilled supply commitments have created huge gaps in vaccination campaigns around the world. One firm estimates that Russia has exported only 4.8% of the roughly 1 billion doses that were promised. Venezuela ordered 10 million doses in December 2020 but has only received slightly over 3 million. Esperita García de Perez got her first vaccination against COVID-19 in May. That, along with her Catholic faith, made her feel better protected against the virus, and she had hoped to get her second shot of the Russian-developed Sputnik V vaccine a few weeks later. But the 88-year-old is still waiting. She was infected with the virus last month, and now her hopes for survival are pinned on the host of medications and home care she is receiving. "They said it was coming, then they said it wasn't, then said I was going to have to wait, then I wasn't going to have to wait, and then I said to myself: 'My God if people can't get the second dose, why did they get the first dose if they can't get the second?" García de Perez said, adding that "you want the certainty and hope that the thing is going to come." Developed in August 2020 and named for the world's first satellite, Sputnik V has been approved in some 70 countries. Russian state media earlier this year broadcast triumphant reports about it "conquering the world" as Moscow aggressively marketed it after wealthy nations kept supplies of Western-developed vaccines for themselves. For a while it was "the only game in town," said Judy Twigg, a professor specializing in global health at Virginia Commonwealth University, but adds that Russia's window of opportunity "to really stake a claim as the savior" in the pandemic is gone. Unlike other COVID-19 vaccines, Sputnik's first and second shots are different and not interchangeable. Manufacturing in Russia has been marred by reports of production difficulties and making its second component. Experts have pointed to limited production capacity as well as the fact that the process is very complicated. The Russian Direct Investment Fund, which bankrolls and markets the vaccine abroad and has production contracts with 25 manufacturing sites in 14 countries, says it "is in full compliance of the Sputnik V supply contracts, including of the second component, after a successful production ramp-up in August and September." The fund's CEO, Kirill Dmitriev, said in an interview with The Associated Press that all supply issues "have been fully resolved." "All of the vaccine manufacturers at some point had some delays in deliveries, so there is not one vaccine manufacturer in the world that didn't have vaccine delivery issues," he said. Although the West largely relied on vaccines made in the U.S. and Europe, such as Pfizer-BioNTech, Moderna and AstraZeneca, many developing nations have sought easier-to-get vaccines from China and Russia. The World Health Organization and the European Medicines Agency have not yet approved Sputnik V for use. In Argentina, the delays in shipments of Sputnik and a virus surge in March led to public pressure on the government to speed up negotiations with other pharmaceutical companies. The Sputnik delays in Argentina and Venezuela have prompted some people to get a different vaccine for their second dose, even though scientists are still studying the effects of such mixing and matching.