The FDA has approved a second booster shot of Covid vaccines made by Pfizer and Moderna for people over the age of 50.

Moderna  (MRNA) – Get Moderna, Inc. Report shares jumped higher Tuesday, while Pfizer  (PFE) – Get Pfizer Inc. Report extended its recent run of gains, after the U.S. Food & Drug Administration authorized the use of a second shot of Covid boosters developed by the drugmakers.

The FDA said adults over the age of 50, as well as those with compromised immune systems, can receiver a booster dose of either the Pfizer or Moderna vaccine at least four months after receiving the first. 

“Current evidence suggests some waning of protection over time against serious outcomes from COVID-19 in older and immunocompromised individuals. Based on an analysis of emerging data, a second booster dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccine could help increase protection levels for these higher-risk individuals,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research. “Additionally, the data show that an initial booster dose is critical in helping to protect all adults from the potentially severe outcomes of COVID-19. So, those who have not received their initial booster dose are strongly encouraged to do so.”

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Pfizer shares were marked 0.7% higher in late-morning trading Tuesday to change hands at $53.65 each. Moderna shares, meanwhile jumped 3.75% to $179.60 each.

The FDA gave full and final approval to the drugmaker’s ‘Spikevax’ Covid vaccine or patients 18 and older in late January, with the first Emergency Use Authorization coming in December of 2020.

Moderna lifted its full-year sales forecast for Covid vaccine sales to $19 billion in late February following additional signed options of approximately $3 billion from various governments around the world.

Orders for Spikevax — its mRNA-1273 coronavirus vaccine — have also been confirmed for 2023 from Canada, the United Kingdom and Taiwan, the company said.

Pfizer said it expects sales of its Comirnaty vaccine are expected to top $32 billion this year, a a $1 billion improvement from its prior forecast, while revenues from its recently-approved Covid pill Paxlovid are forecast to come in at $22 billion.

Late last year, Pfizer said it will sell around 10 million of its Paxlovid treatment, which won Emergency Use Approval (EUA) by the U.S. Food & Drug Administration on December 22, to the United States Department of Health and Human Services.

At $530 per tablet, the cost is around 25% cheaper than the $700 price agreed with Merck & Co. MRK in October to buy 1.7 million doses its ‘molnupiravir’ treatment of “mild-to-moderate Covid in adults who are at risk for progressing to severe forms of disease, or hospitalization.