June 21 (Reuters) - Moderna Inc is adding two new production lines at its COVID-19 vaccine manufacturing plant in Massachusetts, in a bid to prepare for making more booster shots, the Wall Street Journal reported on Monday.

The additions will help Moderna increase overall production capacity by 50% at the plant, the report said citing company officials.

Moderna did not immediately respond to a Reuters request for comment. (Reporting by Mrinalika Roy in Bengaluru; Editing by Shinjini Ganguli)