The U.S. Food and Drug Administration is warning users of the Vet Jet vaccination device to properly lock the device before using it to administer the feline leukemia vaccine.

The device delivers the vaccine, made by Merial, through the skin to cats. The device is used to vaccinate cats with PUREVAX Recombinant Feline Leukemia Vaccine through a transdermal delivery mechanism.

The FDA announcement warns veterinarians and cat owners of possible fracture with the vaccination device.

"Merial recently received three reports of kittens being injured following vaccination using the device," Merial said in a statement. "It appears that in at least two of the cases, the user failed or may have failed to properly lock the nozzle into the device prior to use."

Merial is investigating the incidents and reminding veterinarians to firmly lock the nozzle into the device before injecting a vaccine.

In two of the cases, the nozzle dislodged during vaccination, resulting in a fracture of a kitten’s femur.

Merial is making changes to the Instructions for Use document included in the Vet Jet device to emphasize the importance of locking the nozzle in place before administering the vaccine. The company is also sending a reminder letter to Vet Jet users emphasizing proper use of the device.

The FDA is asking veterinarians and pet owners to report issues with the device to Merial.