#ACR21 L17: Heterologous vs Homologous Booster vax ▶️RTX non-responders to mRNA: Randomized to mRNA 3rd dose vs AZ vax ⭐️Majority of pts develop immune response (humoral and/or cellular) after 3rd dose, no statistical diff b/w groups @Rheumnow https://t.co/cuM9LcEr4u https://t.co/cmNBNSIoOl