Moderna Inc is adding two new production lines at its coronavirus vaccine manufacturing plant, as it prepares to ramp up booster shot production.

The US biotech firm’s plans will increase overall production capacity at its Massachusetts plant by 50 per cent, the Wall Street Journal first reported.

The move indicates that Moderna expects the market for Covid-19 vaccines to endure as lockdown restrictions ease but strains of the virus remain in countries around the world.

Moderna is also reportedly expanding production outside the US, with the aim of almost tripling its global coronavirus vaccine production in 2022 to 3bn doses, up from 1bn doses this year.

“Our plan and our hope is that, as soon as the U.S. has enough doses, we’re allowed to export so we can help as many countries as we can around the world,” Moderna Chief Executive Stéphane Bancel said.

Moderna increased its 2021 sales forecast for its Covid-19 vaccine to $19.2bn at the beginning of May, after it generated $1.7bn in the first quarter of the year.

Meanwhile, latecomer vaccine producers have been emerging and threaten to steal market share, as the sheer scale of the task to inoculate the entire world against Covid-19 becomes clear.

Newcomer Novavax, for example, was forecast to overtake Moderna as the second-largest Covid-19 vaccine maker by revenue next year, with sales of around $17.9bn in 2022, according to estimates made by research company Airfinity.