More than half of U.S. dog owners expressed concerns about vaccinating their dogs, including against rabies, according to a new study published Saturday in the journal Vaccine. The study comes as anti-vaccine sentiments among humans have exploded in the wake of the COVID-19 pandemic.

Pets are now often considered to be a member of the family, and their health-care decisions are weighed with the same gravity. But the consequences of not vaccinating animals can be just as dire as humans. Dogs, for example, are responsible for 99% of rabies cases globally. Rabies, which is often transmitted via a bite, is almost always fatal for animals and people once clinical signs appear. A drop in rabies vaccination could constitute a serious public health threat.

In the new study, the authors surveyed 2,200 people and found 53% had some concern about the safety, efficacy or necessity of canine vaccines. Nearly 40% were concerned that vaccines could cause dogs to develop autism, a theory without any scientific merit.