Jan 20 (Reuters) - McKesson Corp will replace some Moderna Inc COVID-19 vaccines in the United States after they arrived colder than the low end of the required temperature range, the company said on Wednesday.

The company, which is the U.S. distributor of Moderna's COVID-19 vaccines, said some of the gel packs used to maintain appropriate temperatures during shipping on Sunday were too cold and it also impacted some shipments slated for Monday.

Moderna is one of the frontrunners in the COVID-19 vaccine race and expects to supply about 100 million doses to the United States by the end of the first quarter, with 200 million doses in total by the end of the second quarter.

The World Health Organization is currently reviewing shots from Moderna and others including AstraZeneca PLC, China's Sinopharm and Sinovac, and could give emergency go-ahead in the coming weeks or months.

McKesson, which did not provide the number of doses affected by the temperature issue, said it had not shipped the vaccines and would replace them within the next 24 hours.

The doses are currently quarantined, waiting for a determination on whether they are viable, the company said.

McKesson coordinated with the Centers for Disease Control and Prevention to notify each state expecting the shipments of the delay, the company said in an emailed statement.

Moderna, which got emergency use approval from the U.S. Food and Drug Administration in December for its vaccine, did not immediately respond to a Reuters request for comment.

(Reporting by Trisha Roy in Bengaluru; Editing by Sriraj Kalluvila)