Pharmaceuticals giant Johnson & Johnson has halted production of its coronavirus medicine at its production site in Leiden, to focus instead on a potentially more lucrative vaccine against an unrelated virus, the New York Times has reported.

The paper said the production stop is temporary but some are concerned it may impact on the company’s commitment to supply hundreds of millions of doses of its coronavirus vaccine to the developing world.

‘This is not the time to be switching production lines of anything, when the lives of people across the developing world hang in the balance,’ Ayoade Alakija, from the African Union’s vaccine-delivery programme, told the paper.

The company confirmed to the Financieele Dagblad that production at the Janssen plant had been halted but said it had enough vaccines stockpiled to meet its contractual obligations.

The Janssen vaccine may have fallen out of favour in Europe but it is in demand in poorer countries because it requires a single dose to be effective and does not require extreme refrigeration, making it easier to deliver to remote areas.