India will have to spend $1.4 billion to $1.8 billion in the first phase of a coronavirus vaccination programme, even after getting support under the COVAX global vaccine-sharing scheme, according to estimates by the GAVI vaccines alliance.

India plans to inoculate 300 million people over the next six to eight months, likely with vaccines from AstraZeneca, Russia’s Sputnik, Zydus Cadila and its own Bharat Biotech.

Documents reviewed by Reuters underline the scale of the funding challenge India faces to immunise its vast population, with 600 million shots required in the first wave alone for critical workers and people most at risk from COVID-19.

If India got 190-250 million shots of the vaccine under the COVAX facility – a best-case scenario – then the government would need to line up about $1.4 billion to make up for the shortfall, according to an unpublished report prepared for GAVI’s three-day board meeting that began on Tuesday.

On the other hand, if India received a lower allocation of 95-125 million doses, then the cost to the government of procuring additional shots would go up to $1.8 billion.

By comparison, India’s 2020/21 federal budget allocated just under $10 billion to healthcare.

The Indian government has not provided an estimate of the cost of its vaccine programme, though it has said all resources will be provided to protect the population.

GAVI, an alliance of governments, drug companies, charities and international organisations, said it was in discussions with the Indian government over a support package.

“Providing a low range of support would exacerbate the country’s ability to allocate enough resources to mitigate the risks of continued transmission of COVID-19,” the GAVI report said.

The GAVI report identified India’s economic burden due to the pandemic as “disproportionate” and suggested a donor-funded plan of $1.3 billion to secure 190-250 million doses. The plan needs to be approved by the GAVI alliance board.

India also needed $30 million to $80 million for the infrastructure to transport and store vaccines that must be kept at very low temperatures, the GAVI report said.