In my 22 years in the Army, was was PCS’d to Asia, Europe, Central America and the Middle East. I went TDY to Africa and S. America. I’ve had more inoculations and vaccines than, probably, most of you combined. The two worst, that really kicked my ass, were the Gamma globulin & the anthrax vaccine. The Anthrax vaccine was the worst and had 7 boosters to go with it.
The J & J vaccine was a walk in the park compared to those. I had a headache for 48 hours and that was it.