Yes, a longer vaccine needle is recommended for people over a certain weight

Many vaccines, such as the seasonal flu shot and the updated COVID-19 vaccine, are intramuscular, meaning they are injected into a muscle – typically the deltoid muscle of the upper arm – when administered by a healthcare professional.

A viral Instagram post claims people who weigh more than 200 pounds need to receive an intramuscular vaccine with a longer needle in order for it to be effective. One VERIFY reader emailed our team to ask if this is true.

THE QUESTION

Is a longer vaccine needle recommended for people over a certain weight?

THE SOURCES

• U.S. Centers for Disease Control and Prevention (CDC)
• Children’s Hospital of Philadelphia
• CVS Health
• Ilan Shapiro, M.D., chief health correspondent and medical affairs officer at AltaMed Health Services

THE ANSWER

Yes, a longer vaccine needle is recommended for people over a certain weight.

WHAT WE FOUND

The U.S. Centers for Disease Control and Prevention (CDC) does recommend that people over a certain weight receive intramuscular vaccines with longer needles.

For most adults over the age of 18, a 1-inch vaccine needle is long enough to reach the muscle in their upper arm. But the CDC says healthcare workers who are administering intramuscular vaccines may need to use a 1.5-inch needle to reach the muscle in men who weigh more than 260 pounds and women who weigh more than 200 pounds.

The CDC and the Children’s Hospital of Philadelphia both say it’s important to select the proper needle length when vaccinating patients because the “vaccine must reach the desired tissue site for optimal immune response to occur.”

“Depending on the vaccine, we want to make sure, for example, if it goes inside of the muscle, that we have enough length to get there,” Ilan Shapiro, M.D. said. “The worst case scenario is where you actually put the vaccine — instead of actually going inside of the muscle, it ends up in the fat. Well, your body doesn't learn that much from it.”

Shapiro says every person’s body is different, so not everyone who weighs over the CDC’s recommended weight limits will need to be vaccinated with a longer needle. He recommends talking with your doctor or pharmacist if you have any questions.

“In doubt, ask the question because that way you're taking care of yourself and also helping provide the best information in healthcare for you and your family,” Shapiro said.

In an email, a CVS Health spokesperson told VERIFY that their pharmacists “have access to several types of needles, including 1-inch and 1.5-inch needles.”

“They follow CDC guidance in using clinical judgment when selecting which needle length to use for each patient,” the spokesperson said.

VERIFY also reached out to Walgreens and RiteAid but did not hear back by the time of publication.