FDA Issues EUA for Monkeypox Vaccine Administration/Dosing Change

The FDA has granted an emergency use authorization (EUA) to Bavarian Nordic’s Smallpox and Monkeypox Vaccine, Live, Non-replicating (Jynneos) to allow administration of the vaccine via intradermal injection for adults 18 years of age and older who are determined to be at high risk for monkeypox infection. The change to intradermal versus subcutaneous administration is intended to significantly increase the availability of the vaccine because a much smaller dose is needed for an intradermal versus subcutaneous vaccinations.

With the smaller intradermal doses, it is still required to give two doses of the vaccine 4 weeks apart. The EUA also allows the monkeypox vaccine to be administered to individuals under 18 years of age who are determined to be at high risk of monkeypox infection. In individuals under age 18, the vaccine is to be administered by subcutaneous injection as two doses, 4 weeks apart.

This vaccine was approved in 2019 to prevent smallpox in immunocompromised adults, as well as monkeypox.

A 2015 study of the vaccine that evaluated a two-dose series given intradermally compared with subcutaneously found that individuals who received intradermal vaccinations received one-fifth the volume of vaccine received by individuals who received the vaccine subcutaneously. The study showed that intradermal administration produced a similar immune response to subcutaneous administration.

The FDA took the action because in recent weeks monkeypox virus has continued to spread at a rate that has made it clear the country’s current vaccine supply will not meet current demand. Monkeypox was declared a public health emergency on August 4, 2022, but the Biden administration warned that there aren’t enough vaccines to go around. This change will allow the number of available doses of monkeypox vaccine to be five times the number that would be available if the vaccine were given only via subcutaneous injection.