Heartworm sounds like something that only happens to dogs living in warm, buggy climates, but it’s a real risk anywhere mosquitoes exist, including Brooklyn. Understanding how the heartworm prevention shot works helps you decide if it’s the right choice compared to monthly pills, especially if remembering a pill every 30 days isn’t realistic for your household.
Quick Answer: How the Heartworm Prevention Shot Works
The heartworm prevention shot (commonly the ProHeart injection) delivers a slow-release dose of medication under the skin that kills heartworm larvae continuously for 6 or 12 months, depending on the formulation. It removes the need to remember a monthly pill, and a vet administers it during a regular wellness visit.
How Heartworm Actually Spreads
Heartworm isn’t passed dog to dog directly. A mosquito bites an infected animal, picks up microscopic larvae, then passes them to the next animal it bites. Once inside a new host, the larvae migrate to the heart and lungs over several months, growing into worms that can reach up to a foot long.
Left untreated, those worms damage the heart and lungs permanently. That’s why prevention beats treatment here.
Why the Shot Instead of a Pill
Monthly heartworm pills work well, but only if they’re given on time, every time. A missed dose creates a gap where a dog is unprotected. The injectable version removes that human error factor entirely, which is a big part of why more vets are recommending it for dogs whose owners have a hard time keeping a monthly schedule.
What Most Articles Don’t Mention
Most heartworm content focuses only on dogs, but cats can get heartworm too, and it’s actually harder to diagnose and treat in cats than in dogs. There’s no approved injectable heartworm prevention for cats yet, so cat owners rely on monthly topical or oral preventives instead. If you have both a dog and a cat, don’t assume one heartworm prevention plan covers both pets the same way.
Puppies and Older Dogs
Puppies typically start heartworm prevention around 8 weeks old, using monthly options until they’re old enough for the injectable version, usually around 6 months. Older dogs can generally switch to the shot at any age as long as they test negative first and don’t have health conditions that rule out the injectable form. Your vet will factor in age and health history before recommending one option over the other.
What Happens During the Appointment
A vet will typically run a quick heartworm test before administering the shot, since giving preventive medication to a dog that’s already infected can cause a dangerous reaction. The process looks like:
- A blood test to confirm the dog is heartworm-negative
- The injection itself, given under the skin, usually in the scruff or hip area
- A brief monitoring period at the clinic for any immediate reaction
- A follow-up test scheduled for the next renewal window
Cost and Coverage Considerations
The shot’s upfront cost is often higher than a single month of pills, but spread across 6 or 12 months it frequently evens out or comes in cheaper, especially once you factor in the cost of forgetting doses and needing retesting. If your dog is already covered under a wellness plan, ask whether preventive injections fall under coverage options, since coverage varies by provider and often depends on whether your plan includes a wellness add-on.
For comparison, owners who’ve already looked into a pricing guide for dental cleanings will recognize the same logic here: paying for prevention on a schedule beats paying for treatment after the fact. The same goes for staying ahead of required vaccines in New York, since heartworm prevention and required vaccines both fall under the same preventive-care umbrella. And if cost is ever the barrier to keeping a dog protected, a wellness add-on under your plan may offset part of it.
Final Thoughts on the Heartworm Prevention Shot
The heartworm shot trades a monthly reminder for one appointment every 6 to 12 months, and for a lot of Brooklyn dog owners, that trade is worth it. If you’re weighing the shot against pills, or you’re not sure when your dog is due for testing, bring it up at your next visit. The Vet Set can walk you through which option fits your dog and your schedule best.