COVID-19 booster shots of the Pfizer and Moderna vaccines are set to become available for all Americans beginning next month, the U.S. Department of Health and Human Services said in a statement.

"Based on our latest assessment, the current protection against severe disease, hospitalization, and death could diminish in the months ahead, especially among those who are at higher risk or were vaccinated during the earlier phases of the vaccination rollout," HHS said Wednesday morning.

"For that reason, we conclude that a booster shot will be needed to maximize vaccine-induced protection and prolong its durability," the statement said.

The statement said that a plan would go into effect from the week of Sept. 20 "subject to FDA conducting an independent evaluation and determination of the safety and effectiveness of a third dose of the Pfizer and Moderna mRNA vaccines and CDC's Advisory Committee on Immunization Practices (ACIP) issuing booster dose recommendations based on a thorough review of the evidence."

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