Full approval of the Pfizer vaccine will legalize off-label dosing for kids, boosters

Update, 08/23/2021, 3 PM Eastern:

In the hours since the publication of this piece, both the FDA and the American Academy of Pediatrics have come out strongly against off-label dosing of children below 12 years old with the Pfizer vaccine.  Acting FDA Commissioner Janet Woodcock described it as a matter of “great concern.”  The AAP’s announcement came as something of a surprise given the AAP’s previously stated stance in favor of approval of the vaccine for kids based on data already in hand, and makes it more likely that off-label use in this setting will be rare and/or controversial.  Off-label booster doses for vaccinated adults appear less likely to be a flashpoint. 

With the FDA set to fully approve the Pfizer COVID-19 vaccine in the US today, an important and potentially actionable implication of the approval hasn’t gotten enough attention: it will legalize off-label use.

Full approval is being greeted with justified excitement because of the possibility that it will encourage many reluctant unvaccinated people to have additional confidence in the vaccine. But it will also allow doctors to prescribe third doses of the vaccine for adults, and first and second doses for children, before the FDA finishes approving these uses.

Until now, the Pfizer vaccine has been operating under an Emergency Use Authorization (EUA), which strictly limits the settings in which it can be used. By contrast, with full approval, the FDA will still describe which uses are “on label,” but it will be legal for doctors to prescribe in other circumstances, referred to as “off label.” Off-label uses are routine for many drugs, and make up about one in five prescriptions nationwide. For example, a drug with “on label” usage for epilepsy is often prescribed “off label” for migraines.

This would mean that starting Monday, it will immediately be legal for a doctor to prescribe the Pfizer vaccine:

• For children
• As third dose boosters for adults
• As boosters for people who got the Johnson & Johnson or other vaccines
• Adaptively in response to antibody titer results
• In other ways we can’t now anticipate

This may allow people to get the vaccine for these use cases before the FDA approves them. Third doses for adults are expected to begin in late September, and only to be approved for eight months after the second dose, despite data from Israel showing waning efficacy at five months. Dosing for children will likely not be approved until October, despite schools opening now.  The American Academy of Pediatrics is urging the FDA to approve vaccines for kids based on the data it already has in hand.

In order to take the vaccines off label, members of the public would need a doctor’s prescription, and to find a pharmacy which will honor the prescription. This will be eased by the arrival of Pfizer doses to primary clinics, but it’s unclear when that will happen. It’s also unclear whether major pharmacies will honor off label prescriptions — although I suspect they will.

For this and other reasons, it’s unclear whether off label use of the Pfizer vaccine will be a trickle or a flood, and whether it will become a controversial topic or proceed with a relative lack of drama.

We’ll be monitoring the situation after full approval lands, and may report more as events evolve.