Health specialists announced on Thursday that India’s export ban on COVID-19 doses risks dragging the battle against the pandemic “back to square one” unless wealthy nations intervene to plug a gaping hole in the COVAX global vaccine-sharing scheme.

COVAX, which is critical for poorer countries, relies on AstraZeneca jabs made by the Serum Institute of India, the world’s biggest maker of vaccines. It was already around 100 million shots short of where it had planned to be when India halted exports a month ago amid a spike in coronavirus cases there.

The global experts said rich countries with plentiful vaccine stocks must now share them immediately, at scale, otherwise the pandemic could be prolonged as the world grapples to contain a virus that keeps spreading and mutating.

“It is a huge concern,” said Anna Marriott, health policy manager at the global charity Oxfam. She and others said it was imperative that wealthy countries and regions make good on their rhetoric and share excess vaccines now.

“The current approach that relies on a few pharma monopolies and a trickle of charity through COVAX is failing – and people are dying as a result.”

A highly transmissible new variant of COVID-19 first identified in India has spread to many countries around the world.