Don’t Change That Needle!

For decades, many veterinary professionals have been taught that changing the needle after drawing up a vaccine is the gold standard for patient comfort. It is a habit rooted in good intentions and concern for animal welfare. But what if that routine step does not actually improve the patient experience and instead adds unnecessary waste, cost, and risk?

Two recent publications in JAVMA, both led by Dr. Rachael Kreisler at Midwestern University, provide a clear and reassuring answer. The evidence shows that we can safely keep the same needle without compromising animal comfort, while also advancing sustainability in everyday clinical practice.

Challenging a Long-Held Assumption

In a randomized, double-blinded, controlled crossover study of 75 client-owned dogs, researchers evaluated both physiologic and behavioral responses to vaccination when needles were replaced versus when they were not. Heart rate responses and behavioral reactions did not differ between the two approaches. Even more telling, the veterinarians administering the injections could not identify which needle had been replaced at better than chance levels.

In other words, from both the patient’s perspective and the clinician’s hands, there was no detectable benefit to changing the needle. This finding aligns with earlier in-vitro work showing no clinically meaningful difference between replaced and nonreplaced needles. Together, these data challenge a deeply ingrained assumption and invite us to rethink what truly constitutes best practice.

What About Needle Dulling?

One of the most common reasons veterinarians cite for changing needles is concern about dulling after puncturing a vaccine vial septum. A companion study explored this concern directly by combining a survey of veterinary professionals with laboratory testing of needle sharpness.

While 76 percent of respondents reported routinely changing needles after drawing up a vaccine, objective testing told a different story. Passing a needle through a vial septum had only a minimal effect on sharpness when measured with a force meter and microscopic visualization. In fact, factors such as needle brand, gauge, and the force used to penetrate the septum had a greater impact than the act of vial puncture itself.

The largest defect observed after septum passage was 52 micrometers. In human medicine, needle defects of this magnitude are considered indistinguishable from unused needles in terms of perceived pain. When gentle vial puncture technique is used, changing the needle simply does not provide the benefit many of us were taught to expect.

Why This Matters for Sustainability

At first glance, a single needle may seem insignificant. But across thousands of injections per year, routine needle changes add up to meaningful volumes of regulated medical waste, additional supply costs, and increased risk of needlestick injury to veterinary teams.

By demonstrating that needle replacement does not improve patient comfort, these studies give the profession permission to let go of a practice that no longer serves its intended purpose. This is a powerful example of how evidence-based medicine and sustainability can reinforce one another. Reducing unnecessary waste does not require compromising care. In this case, it strengthens it.

Sustainability in veterinary medicine is often framed as a large, complex challenge. Yet some of the most impactful changes are simple adjustments to everyday routines. This is exactly the kind of win-win solution the profession needs more of.

From Evidence to Everyday Practice

What does this mean for clinics and teaching hospitals?

It means that using the same needle to draw up and administer vaccines is clinically acceptable when proper technique is used. It means fewer sharps disposed of, fewer opportunities for accidental needlestick injuries, and lower material costs over time. It also means aligning daily clinical decisions with our broader responsibility to steward resources wisely while maintaining high welfare standards.

Just as importantly, these studies highlight the value of questioning long-standing norms and testing them rigorously. Many sustainability opportunities in veterinary medicine are hiding in plain sight, embedded in routines that persist simply because “that’s how it’s always been done.”

A Simple Call to Action & Green Paw Opportunity!

If your clinic still routinely changes needles after drawing up vaccines, consider reviewing these findings with your team. Discuss gentle vial puncture technique, evaluate current protocols, and decide together whether this is a change that makes sense for your practice.

Small, evidence-based shifts like this one are how sustainability becomes embedded in veterinary medicine. They remind us that progress does not always require sweeping transformation. Sometimes, it starts by realizing we do not need to use additional materials, like needles, at all.

For clinics working toward Green Paw certification, evidence-based changes like eliminating unnecessary needle changes could be one of your clinic actions around waste reduction… you would be making sustainability part of routine clinical care rather than an added burden!