FDA warns against delaying, changing COVID-19 vaccine dosage schedules

Coronavirus: Delaying the second dose


The U.S. Food and Drug Administration (FDA) is warning people not to delay getting the second dose of a COVID-19 vaccine.

The announcement came after Britain made the decision to push back the timeline for the second dose of their vaccines up to 12 weeks in an effort to get more people vaccinated.

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Americans getting the Pfizer BioNTech vaccine are told to get the second dose 21 days after the first dose.

It’s 28 days between the Moderna vaccine doses.

The FDA said making any changes to the authorized dosing or schedules is “premature and not rooted solidly in the available evidence.”

“We wouldn’t want people thinking they’re protected or even partially protected after their first dose when they’re really not,” said Dr. Marci Drees, Chief Infection Prevention Officer for ChristianaCare. “Something like 98 percent of people in the trial did get their dose on time so we don’t have any data for a reduced dose or an expanded interval.”

Health experts said delaying a second dose or not getting a second one altogether could also lead to potential health risks.

“There’s a lot of questions that we have about a single dose that I think could be an issue,” said Dr. Kathryn Stephenson, Assistant Professor of Medicine at Harvard Medical School. “If you have only partial immunity, occasionally that can encourage the virus that’s circulating to maybe develop some more resistance.”

Stephenson said the focus should be on making sure there are enough systems in place to give people the vaccinations.

“We are at risk of kind of getting distracted by this one versus two doses and missing the big issue which is that we need to have more people vaccinating, more clinics set up,” Stephenson said.

Denmark approved up to a six-week delay between COVID-19 vaccine doses and Germany is considering a similar move.