The United States Centers for Disease Control and Prevention notified public health authorities in all 50 states and five large cities to begin preparations to distribute two unidentified vaccines in late October or early November, the New York Times reported Wednesday.

What Happened: The two vaccines which the CDC is calling — Vaccine A and Vaccine B — will be distributed to health care workers and other persons falling in high-risk groups, according to the Times.

The agency has reportedly spelled out technical specifications for both vaccines including requirements for their shipping, mixing, storage and administration.

The specifications indicate that these vaccines are likely ones being made by Pfizer Inc (NYSE:PFE) and Moderna Inc (NASDAQ:MRNA), which are in advanced clinical trials, as per the Times.

The scenarios reportedly assume that the two vaccines will be deemed safe and effective enough to receive an emergency authorization from the Food and Drug Administration by the end of October.

Vaccine A, which may be Pfizer’s product is likely to have 2 million doses ready by October and Vaccine B, the one most likely made by Moderna, would have one million doses ready by that period, according to the documents. 

The documents state that tens of millions of doses would be ready by the end of the year.

Price Action: Pfizer shares closed 0.84% higher at $37.20 on Wednesday and gained 0.30% in the after-hours session. On the same day Moderna shares closed nearly 2.2% higher at $64.72 and rose almost 0.3% in the after-hours session.