America is a very pet-loving nation. There are a number of different sources one can turn to, but after viewing a number of them, I feel confident in saying that the most numerous pets in the United States are freshwater fish (139.3 million). Most sources list cats as the second most common household pet in the United States (94.2 million), even though more households own a dog than a cat.

Dogs are the third most numerous household pet (89.7 million), followed by birds (20.3 million), saltwater fish (18.8 million), small animals (14 million), reptiles (9.4 million) and horses (7.6 million). All toll, the number of pets in the United States number nearly 400 million or more.

Of all of the millions of pets in America, none is responsible for more allergies than cats. According to one source:

About 10% of the U.S. population has pet allergies and cats are among the most common culprits. Cat allergies are twice as common as dog allergies. But contrary to what you might think, it’s not the fur or hair that’s the real problem. People with cat allergies are really allergic to proteins in the cat’s saliva, urine, and dander (dried flakes of skin).

How do these tiny proteins cause such a big allergic reaction in the body? People with allergies have oversensitive immune systems. Their bodies mistake harmless things — like cat dander — for dangerous invaders and attack them as they would bacteria or viruses. The symptoms of the allergy are the side effects of your body’s assault on the allergen, or trigger.

Keep in mind that even if you don’t have an actual cat allergy, your cat can still indirectly cause your allergies to flare up. Outside cats can bring in pollen, mold, and other allergens on their fur.

Some people are born with allergies to cats and some develop cat allergies over time. I’m one of them. I had a cat once and had no problems, but as I’ve aged and my immune system has weakened, I have developed a strong allergy to cats. My eyes water and itch, my nose runs like crazy and I get congested and develop a headache. My cat allergy has been so severe on occasion that it caused ear problems, including a perforated eardrum on one of those occasions.

Up until now, there isn’t a whole lot people with cat allergies can do except avoid cats or people who own cats. But that may be about to change, as reported:

If you love cats but are allergic to them, a team of scientists in Switzerland could have the purrfect solution for you.

HypoPet AG, a Swiss-based company, announced it has developed a vaccine called HypoCat that works by “immunizing cats against their own major allergen, Fel d 1,” found in cat dander to which 10 percent of humans are allergic, according to the Journal of Allergy and Clinical Immunology.

“Our HypoCat vaccine is able to produce high levels of antibodies in cats,” HypoPet AG CEO Gary Jennings wrote in a statement. “These antibodies can bind and neutralize the Fel d 1 allergen produced by the animals.”

In other words, the cat would be administered the vaccine, not their allergic owner.

Note, that the vaccine is given to the cat and not the person. That means that a person may not have an allergic reaction to his/her vaccinated cat, but could still react to any other non-vaccinated cat. That means it’s not a cure-all but could help tens of thousands of people who want to own a cat but are allergic to them. It’s a step in the right direction and may, in time, be as important as having all cats spayed and neutered.