FDA Warns Against Changes to Authorized Dosing Schedules of COVID-19 Vaccines

Officials with the FDA took a stance on the authorized dosing schedules for coronavirus disease 2019 (COVID-19) vaccines, stating that all health care professionals should continue to administer 2 full doses of the vaccine, according to a statement.¹

The statement comes after discussions about altering the dosing schedule in order to immunize more of the public against COVID-19. Proposed alternatives have included reducing the number of doses, extending the length of time between doses, changing the dose, or mixing and matching vaccines.

“At this time, suggesting changes to the FDA-authorized dosing or schedules of these vaccines is premature and not rooted solidly in the available evidence,” FDA Commissioner Stephen M Hahn, MD, and Peter Marks, MD, PhD, director for the Center for Biologics Evaluation and Research, said in the statement. “Without appropriate data supporting such changes in vaccine administration, we run a significant risk of placing public health at risk, undermining historic vaccination efforts to protect the population from COVID-19.”  

Agency officials noted that changing the dosing schedule without proper evaluation of an alternative regimen in clinical trials could be harmful, “as there is some indication that the depth of the immune response is associated with the duration of protection provided.”

Although clinical trial data suggested some protection following first dose of the vaccine, the FDA cautioned that those participants who did not receive 2 vaccine doses at either a 3- or 4-week interval were only followed for a short period of time. “We cannot conclude anything definitive about the depth or duration of protection after a single dose of vaccine from the single dose percentages reported by the companies,” Hahn and Marks noted.

Currently, the available data support the use of 2 specified doses of each vaccine at specified intervals. For the Pfizer-BioNTech vaccine, the interval is 21 days between the first and second dose. For the Moderna vaccine, the interval is 28 days between the first and second dose.

Although White House officials set a goal of vaccinating 20 million Americans by the end of 2020, just 4.5 million individuals have received their first dose of the vaccine as of Monday.²

^References

1. FDA Statement on Following the Authorized Dosing Schedules for COVID-19 Vaccines. FDA statement. FDA; January 4, 2021. Accessed January 5, 2021. https://www.fda.gov/news-events/press-announcements/fda-statement-following-authorized-dosing-schedules-covid-19-vaccines

2. COVID-19 Vaccinations in the United States. CDC. Last Updated January 4, 2021. Accessed January 5, 2021. https://covid.cdc.gov/covid-data-tracker/#vaccinations