You May Need a Longer Needle for Your Next Vaccine.

Like many other Americans, I volunteered at a mass vaccination site in 2021. Under a tent, a group of medical workers loaded syringes, which staff then carried to lines of cars where vaccinators inserted preloaded needles into weapons. Each person received the same vaccine, the same quantity, and the same size needle.

But different organisms need different lengths of needles, and the length of the needle can affect how well the vaccine works in your body . If you are going to get the COVID vaccine this year, or any vaccine for that matter, this is something you should pay attention to. If you identify as a woman and weigh over 200 pounds, or as a man identify over 265 pounds, you may need a longer needle—and in all likelihood, you will have to advocate for it.

The needle must enter the muscle

Most vaccines work by injection into a muscle , and vaccinators typically use the deltoid muscle. This is the shoulder muscle, and it is located under a layer of fat, which absolutely everyone has. Ideally, the needle (often one inch long for everyone from small children to adults) penetrates the fat and enters the muscle.

But bodies are built differently, and if you have more fat over muscle, one inch may simply not be enough. For this reason, the CDC has long recommended that body size be taken into account when vaccinating, and that adults be given needles that range from one to one and a half inches in length.

While body weight is one way to determine this need, body shape and size are key. Vaccinators are instructed to make the decision during a consultation with the patient before vaccination. And a longer needle is not more painful (it is not a needle with a wider circumference), so there should be no significant barrier to acting according to CDC guidelines.

How was I supposed to know about this?

It’s not really the patient’s responsibility – we all rightly assume that when we get a flu shot or vaccine, the equipment used is correct and we don’t have to think about it. There is good reason to believe that: Ultimately, health care workers should receive training that includes this CDC recommendation.

During the pandemic, vaccinator qualifications were downgraded out of necessity, but even so, most vaccine sites required on-site training that would include this CDC data.

The problem is that weight bias in healthcare is widespread and well known. I interviewed six vaccinators who said they worked at mass vaccination sites across the US during 2021. Only half were aware of the CDC recommendation, and only one said they adhered to the recommendation and were armed with different sized needles. I know that at my mass vaccination site in Arizona in early 2021, we did not use different length needles. Most alarmingly, one of the other vaccinators suggested that despite knowing the recommendations, health workers dismissed these concerns. “I have been a vaccinator in mass and small clinics and I can tell you that weight recommendations were categorically rejected by doctors and nurses. I would let the vaccinators worry about this, not the patients. You’ll find that most pharmacies only carry one size.”

I called three pharmacies distributing the current COVID vaccine: CVS in midtown Manhattan, Walgreens in Chicago, and Rite Aid in Los Angeles, and spoke with a man who identified himself as the pharmacy manager at each and asked if they were using different vaccines. needle lengths based on weight for the current COVID vaccine. Only Walgreens indicated that it did. Los Angeles and New York said they used one-inch needles for everyone. When I asked them for needle length recommendations, both seemed surprised by the information.

What happens if I can’t find a needle that is long enough?

We know that intramuscular vaccines must be injected into the muscle and that a one-inch needle does not always reach the muscle. Less clear is how this affects the effectiveness of vaccines, including the COVID vaccine. The way to measure this is to measure the titer, which measures the amount of antibody or virus in the body after an injection. In the case of COVID, we don’t have good measurement tools, so there’s no effective titer to use. But in 2010, a study was conducted on obese teenagers who received the hepatitis B vaccine. Longer needles resulted in an 80% increase in titer after vaccination.

However, how the vaccine is administered also matters. More experienced vaccinators may be able to administer the vaccine at an angle that still penetrates the muscle. However, there is no suggestion that vaccinations using shorter needles than recommended are of no use. Still, it is better to vaccinate with a standard needle than not to vaccinate at all.

How do I know if I have a longer needle and how do I ask for one?

The needle length is not listed in any of the entries, so you will likely never know what length you got previously. However, armed with this knowledge, you will be better able to advocate for a longer needle if you need one in the future. I reached out to Dr. Shradha Chhabria, co-author of the 2022 paper mentioned above, MD, who specializes in obesity medicine, for advice on patients who may need extra needle length.

She explained that there is a scientific basis for this request, which will hopefully make it easier to speak up. “This is a compelling CDC standardized practice that is part of any standardized vaccination training as recommended by the CDC ,” Chhabria said. She encouraged patients to speak up on their own behalf. “I think anyone who is going for a vaccine, who is aware of these weight-based recommendations and the fact that they may have improved immunity from the vaccine if the correct length of needle is used, should feel very empowered to speak up and say: hey, I understand the CDC recommends using a 1.5 inch needle for my weight. Do you have 1.5″ needles in stock today?’ Any vaccinator should understand that this is the standard of care.”

If a vaccinator doesn’t have the appropriate length of needle, Chhabria said to ask if they can get one, but ultimately it’s better to get a shot with less effectiveness than not to get one at all.