Are Spikevax and mNexspike always interchangeable?

They are only interchangeable for people age 12 years or older. Spikevax and mNexspike are both mRNA-based COVID-19 vaccines manufactured by Moderna. Spikevax is given as a 0.25 mL (25 mcg) dose for ages 6 months through 11 years and 0.5 mL (50 mcg) for ages 12 years and older. The mNexspike dose as 0.2 mL (10 mcg) for ages 12 years and older. Each of these three options is packaged as a manufacturer-filled syringe in the United States. It is important to verify the product name, age indication, and dose volume before every injection.