Hoarding Covid-19 vaccines could cost wealthy countries at least $4.5tn (£3.29tn) in lost income this year, according to a new study that argues vaccinating poorer countries against Covid-19 is not just a moral imperative but an economic one. The cost of fully funding the World Health Organization’s programmes to deliver Covid-19 vaccines and treatments to developing countries – currently $27bn away from their 2021 funding targets – would be dwarfed by the cost of not doing so, according to research commissioned by the International Chamber of Commerce, an international business lobby group, released on Monday. In the most extreme scenario, with populations in developed economies such as the UK’s largely protected from Covid-19 within a few months but only negligible vaccine doses administered in developing countries, global losses this year would amount to at least $9tn – more than three times the size of the UK’s economy. Because rich economies are dependent on international supply chains that include unvaccinated countries they would bear almost half the cost of this economic drag, the report said. “Advanced economies therefore have a clear economic incentive to speed the distribution of vaccines on a globally coordinated basis,” said the team of researchers from institutions including Harvard and Istanbul’s Koç University. Even if developing countries were able to vaccinate half their populations by the end of the year – an unlikely scenario on the current trajectory – lost global GDP would still amount to $4.4tn, according to the study. More than 40m vaccine doses have been administered in mostly wealthy countries since December, but middle- and lower-income nations are lagging far behind, with many not projected to be significantly immunised until at least 2025, according to some estimates. Covax, a global compact to equitably share vaccines, says it is on track to administer enough doses to cover only about 27% of populations in its member countries this year. Experts have been warning that this disparity will slow the economic recovery from the pandemic, but the paper released on Monday estimates the cost to be substantially higher than previous forecasts. It argues that the ongoing spread of the pandemic in developing and emerging markets will mean fewer customers for exports from wealthy ones where the virus has been brought under control through vaccines. Alongside this, the report also takes into account interruptions to supply chains for things such as construction material, car parts and textiles, which would have to stop and start due to ongoing Covid-19 outbreaks and lockdowns in a global market of vaccine haves and have-nots. “Even if a given country has access to the vaccine, it experiences a sombre recovery with a drag on its GDP when its trading partners do not have access to vaccines,” the study said. “In the absence of global coordination, countries that successfully contain the virus will still struggle as long as the other countries do not contain it.”