Even before the vaccine, therapy dogs were already being used at the children's hospital.
甚至在接种疫苗之前，该儿童医院就已经开始使用治疗犬了。
英语百科
Vaccine therapy
Vaccine therapy is a type of treatment that uses a substance or group of substances to stimulate the immune system to destroy a tumor or infectious microorganisms such as bacteria or viruses.