for individuals to mix booster shots. what under what circumstances would you recommend that to your patients? not very commonly. i don t know that i would routinely recommend booster shots for instance, if you got two doses of the pfizer vaccine, my recommendation is go with the third dose. that s pfizer, that s what i did. for the simple reason there s going to be a lot more data collected on it, and it works really well. same with the moderna. in the case of the moderna vaccine, actually immunity s not really declining that much. so it s not like you have to rush out and do it. i think rochelle walensky said, the cdc director, said walk, don t run. with the j&j vaccine, the most common new england is get the second dose . the one hedge young women who are pregnant where the risk of getting thrombotic disease, clotting disease is higher.