Moderna Inc raised its 2021 sales forecast for its COVID-19 shot by 4.3% to $19.2 billion on Thursday, reflecting demand from countries looking to return to normalcy through rapid vaccine rollouts.

Deals for "booster" doses, nations looking to stock up supplies for 2022 and beyond and a likely authorization for use of the vaccines in kids have led Moderna and its larger rival Pfizer to ramp up their supplies.

Moderna said an initial analysis of a study in adolescents aged 12-17 years showed an efficacy rate of 96% for its vaccine.

The company has also been working on a new version that could extend the time the vaccine can be stored in refrigerator temperatures, making it easier to distribute, especially in lower-income countries.

However, Moderna shares along with other global vaccine makers fell in premarket trading following US President Joe Biden's decision to support a waiver of intellectual property rights for COVID-19 vaccines.

While the move is aimed at increasing vaccine availability in poorer countries, it could potentially hit sales of COVID-19 vaccines.

Chief Executive Stéphane Bancel said the company could sign more deals with countries for supply of the vaccine in 2022 than in 2021.

Earlier this week, Pfizer raised its full-year forecast for the COVID-19 vaccine it developed with Germany's BioNTech to $26 billion.

Moderna had in February forecast vaccine sales of $18.4 billion. In the first quarter ended March 31, its vaccine brought in sales of $1.7 billion, helping the drugmaker record a profit for the first time ever.

The company said it plans to file for full approval of the vaccine in the United States this month.