The latest California data shows increased rates of emergency room visits, hospitalizations, and deaths from dog bites, with new records set after COVID lockdowns. In 2022, there were 48,596 ER visits for dog bites in California, or 125 visits per 100,000 residents, a 70% increase in the rate of visits from 2005, according to the state Department of Health Care Access and Information.

The rate of hospitalizations roughly doubled from 2006 through 2022. And although deaths from dog bites are extremely rare, the death rate in California rose about 70% during roughly the same period, with 28 deaths in the state from 2018 through 2022. Nationally, dog bites were the underlying cause of 96 deaths in 2022, while the death rate more than doubled from 2005 to 2022, according to data from the U.S. Centers for Disease Control and Prevention.

Even before the pandemic, more Americans were welcoming dogs into their homes. The American Veterinary Medical Association estimates that households nationwide owned about 86 million dogs in 2020, up from about 62 million in 2001. The pandemic accelerated that trend as millions more people adopted puppies to provide companionship during a period of isolation.

But lockdowns kept puppies from being socialized, said Elizabeth Stelow, chief of the Behavior Service at the UC Davis Veterinary Medical Teaching Hospital. For healthy development, she said, puppies need to learn acceptable behavior between their first three weeks and 16 weeks of life.

“You’re supposed to socialize that puppy to new kinds of people, new kinds of animals, new kinds of places, new kinds of everything,” Stelow said. “Nobody was able to do that. So we’re seeing the effects of that all the time right now.”

As poorly socialized puppies turn into adults, their bites can do more harm. From 2021 to 2022, the number of ER visits in California for dog bites grew 12%, marking the highest yearly total to date. Though a recent study did not show a nationwide increase in the rate of ER visits for dog bites from 2005 through 2018, several national studies did show a rise in the proportion of ER visits due to dog bites during the pandemic.

Another potential explanation is the popularity of breeds some people say are aggressive. Kenneth Phillips, one of the nation’s most prominent lawyers specializing in dog bite litigation, pinned much of the blame on pit bulls, which have become one of the most popular breeds in America. “Every study always comes up with the same conclusions, which is that this is the dog that does the most damage,” he said.

Some studies show pit bull bites are often associated with serious injury, while other studies assert that they are not a disproportionate threat. Stelow said a socialized and trained pit bull is not more dangerous than dogs of other breeds. “Why is the No. 1 dog demographic for dog bites pit bulls? Because they’re a huge percentage of the canine population in California,” she said.

Phillips said animal shelters are increasingly under pressure to euthanize fewer dogs, meaning people wind up adopting more aggressive dogs without knowing it. The number of “no-kill” animal shelters has increased sharply in the last several years, according to Best Friends Animal Society. However, even no-kill shelters may euthanize aggressive dogs that cannot safely be adopted. A 2019 California law requires animal shelters and rescue groups to disclose a dog’s bite history to anyone adopting it.

A few years ago, a German shepherd was sitting next to a garage as Sacramento, California, postal worker Jacob Studer approached the driveway to make a delivery. The dog crept toward Studer as its owner called the dog. Studer said the dog attacked when he began to pull up his mail bag.

“The dog jumped up, grabbed my arm, bit my arm, and then pretty much ripped my sleeve up and knocked me to the ground,” he said. “I fell backwards and did almost like a little somersault.”

Studer was not seriously injured and didn’t go to the hospital. However, he said the dog’s owner decided not to keep it.

State figures and a recent study by public health researchers show that, in California, children and young adults are the age groups most likely to make ER visits for dog bites. Nationwide, children under 5 were more than twice as likely to die from dog bites as members of other age groups, according to CDC data from 2018 to 2022.

Randall T. Loder, professor emeritus of orthopedic surgery at Indiana University School of Medicine, said the most serious injuries from dog bites often involve the head and neck, making little children especially vulnerable.

“Younger people, they don’t understand the risks of a dog,” said Loder, who authored a recent study of tens of thousands of dog bite injuries. “They’re vulnerable.”

His study estimated the annual health care cost of treating dog bites is at least $400 million nationwide. Dog bites can lead to infections or transmit serious diseases like rabies.

In California, serious dog bite injuries are more common in rural areas. The rate of ER encounters for dog bites in 2022 was almost 50% higher in counties with fewer than 200,000 people. Modoc, Inyo, Lake, and Siskiyou counties had the highest rates of ER encounters.

Stelow said dogs in rural areas are often not as socialized as their urban cousins. Rural residents also tend to have more dogs.

Stelow said owners of aggressive dogs should reach out early to a veterinarian, particularly one specializing in animal behavior. She said owners should learn to recognize anxiety in dogs and understand their body language. For instance, dogs that are frightened may attempt to flee, fight, fret and fidget, or freeze.

“For the dogs that are already in that situation where they are biting people,” Stelow said, “they need to come see someone who can work with the emotional damage that’s been done and try to correct it.”

Phillip Reese is a data reporting specialist and an associate professor of journalism at California State University-Sacramento.

This article was produced by KFF Health News, which publishes California Healthline, an editorially independent service of the California Health Care Foundation.