The launch in India of a new COVID-19 vaccine developed jointly by the Serum Institute of India (SII) and US-based biotech firm Novavax is likely to be delayed to September, said Adar Poonawalla, the CEO of Serum. He had said in January that the vaccine, named Corovax, was expected to be launched by June.

Poonawalla said the trials of Corovax had kicked off in India, but did not say why the vaccine launch was delayed.

“It has been tested against African and UK variants of #COVID19 and has an overall efficacy of 89%,” tweeted Poonawalla, “Hope to launch by September 2021!”

Poonawalla said earlier this month that a temporary US ban on exports of critical raw materials could limit the production of coronavirus vaccines such as Novavax.

India said on Friday it would prioritise domestic COVID-19 inoculations amid rising coronavirus case and had told international buyers of its decision.