Go to the EEOC website. Read the very specific criteria for religious exemption. Craft your request directly to those points. Do not stray, expound, nor try and justify. You do not have to -- just state. Be polite but use phrases such as "per EEOC guidelines ___" to let them know you have done your homework. Most HR departments are just covering their asses against government prosecution and liability from lawsuits by litigious coworkers by placing the vaxx requirement on their employees as they believe they must and don't really give a shit about the shot. Help them help you by exactly checking the boxes that the EEOC sets forth. That is what they'll need to rebut pressure from above if ever challenged. Edit: Spoken from experience. Got mine from a very liberal employer.