Children Inflicted by Lyme Disabilities Act of 2021 or the CHILD Act of 2021 This bill expands the applicability of certain special education provisions to children with Lyme disease or other tick-borne diseases. (Lyme disease is the most common vector-borne disease in the United States. The disease is transmitted to humans through the bite of an infected blacklegged tick and, if left untreated, can spread to joints, the heart, and the nervous system.) Specifically, the bill defines child with a disability for purposes of the Individuals with Disabilities Education Act to include a child who needs special education and related services because the child has a health impairment resulting from Lyme disease or another tick-borne disease.