“Vaccination is not morally obligatory and so must be voluntary,” the bishops said. “There is a moral duty to refuse the use of medical products, including certain vaccines, that are created using human cells lines derived from abortion; however, it is permissible to use such vaccines only under case-specific conditions—if there are no other alternatives available and the intent is to preserve life.”

“A person’s assessment of whether the benefits of a medical intervention outweigh the undesirable side-effects [is] to be respected unless they contradict authoritative Catholic moral teachings,” the bishops added. “A person is morally required to obey his or her conscience.”