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Elise Amend

Syringe size and supply issues continue to waste COVID-19 vaccine doses in United States

Science’s COVID-19 reporting is supported by the Heising-Simons Foundation.

Piled up in hospital storage closets—and even in boxes donated to an animal shelter—sit syringes the U.S. government has provided to administer COVID-19 vaccines. They’ve been set aside because they're not effective at extracting all available shots from the multidose vials supplied by vaccinemakers.

It became clear in December 2020 that Pfizer's and Moderna's vaccine vials included more than the number of doses displayed on their labels. The U.S. Food and Drug Administration (FDA) soon authorized shot-givers to pull out at least one extra dose if they could. But vaccination sites say they are still receiving equipment kits from the federal government's vaccine program, Operation Warp Speed, that don’t consistently contain the right syringes for that task. Some have bought better syringes themselves; those who can't afford to upgrade say they see doses go to waste every day.

“We are in a lot of flux right now trying to meet [vaccination] demand, and the ideal supplies may not be there," says Anne Burns, vice-president of professional affairs at the American Pharmacists Association.

It's common for vaccine manufacturers to overfill their vials slightly to account for regular waste as doses are prepared and administered. The Pfizer vial originally intended for five 0.3-milliliter (ml) doses, or 1.5 ml total, actually contains 2.25 ml of vaccine once the liquid is diluted for injection. Moderna vials intended for 10 0.5-ml doses, 5 ml total, often have 6 ml. As the pandemic continues to kill hundreds in the United States every day, this excess vaccine—up to two extra doses in Pfizer's five-dose vial and Moderna's 10-dose vials—can save lives.

But getting those extra doses out requires some skill—and the right syringe. The standard vaccine syringe holds 3 ml, but a thinner, 1-ml syringe is often used for vaccines with small doses, like Pfizer's and Moderna’s. Because it's narrower, the smaller syringe traps less liquid between the plunger and the tip of the needle after a dose is expelled. And specially designed “low dead-volume” syringes, which come in both sizes, have plungers that slide all the way down to the needle to eliminate most of this trapped liquid.

A low dead-volume syringe (bottom) reduces wasted vaccine by trapping less liquid after an injection than a standard syringe (top).

FAQ for Maximizing COVID-19 Vaccine Doses/United States Pharmacopeia

“It takes a bit of care to use these large, monstrous 3-milliliter syringes, with a high dead-space system, to get the exact dose,” says Daniel Griffin, a physician at New York-Presbyterian Hospital who oversees the vaccination process at the health care company Optum, which runs about 100 U.S. vaccination sites.

Unfortunately, the larger standard syringes are sometimes the only ones on hand. “We would ideally like to use 1-milliliter and low dead-volume syringes for everyone, but the reality is that there is no supply,” says Michael Ganio, director for pharmacy practice and quality at the American Society of Health-System Pharmacists, which recently published an FAQ on syringe and needle selection for pharmacists administering COVID-19 vaccines.

After FDA’s blessing, the sixth doses in Pfizer’s vials now count toward the company's commitment to provide 200 million doses to the United States by the end of July, The New York Times reported. The change makes it even more important that the government provide the right equipment to make sure the doses already paid for are not wasted.

McKesson, the company that distributes the vaccine kits for the federal government, announced in January it would create “megasupply kits” for the Pfizer vaccine with syringes and needles that would allow the use of all six doses. A spokesperson for the U.S. Department of Health and Human Services (HHS) confirmed to Science that all the Pfizer kits currently shipped consist of 1-ml syringes, the majority of which are low dead-volume syringes.

And organizations contacted by Science say they have started to receive the new Pfizer kits. But Moderna kits remain unchanged, containing the standard 3-ml syringes. Given that the United States has bought 300 million Moderna doses so far, it stands to waste some 30 million doses by failing to enable vaccinators to draw out an 11th dose.

The HHS spokesperson told Science that the agency is “committed to maximizing use of every vaccine dose available” and working with distribution partners, but "there is no plan to provide low dead-volume syringes with the Moderna kits due to limited supply." For now, Moderna kits can include either regular or low dead-volume 1-ml or 3-ml syringes based on availability.

SOMOS, a nonprofit organization that has administered more than 90,000 vaccine doses in New York, alerted state authorities about the inadequate syringes in February and started to receive 1-ml syringes in the Moderna kits, chairman Ramon Tallaj says. But in the past few weeks, kits started arriving with 3-ml syringes again, he says.

The sizes and types of syringes in the Warp Speed kits are “all over the place,” says Jenn Wheeler, chief pharmacy officer at Community Health Alliance, a federally qualified health center in Washoe County, Nevada that administers about 5800 vaccine doses per month across seven sites. In her team's experience, only about 4% of the syringes in the Moderna kits are 1-ml, she says. Her center has compensated by buying its own low dead-volume syringes and donating most of the government-supplied syringes to a local animal shelter.

Optum's vaccination sites have also bought their own syringes to replace the inefficient ones in the Moderna kits, Griffin says. The purchases afford them hundreds of extra shots every week.

But some clinics struggle to find more efficient syringes for sale. Pharmacist Gretchen Garofoli, of West Virginia University and Waterfront Family Pharmacy in Morgantown, West Virginia, has continued to vaccinate people with the Moderna vaccine and 3-ml syringes sent by the government because she found no alternatives at the wholesale pharmacy.

The demand for low dead-volume syringes has gradually slowed since January as the updated government-supplied Pfizer kits began to be circulated, notes pharmacist Jessica Daley, vice president of strategic supplier engagement at the health care company Premier Inc, which has helped its more than 4100 member hospitals find and collectively purchase syringes. But demand still exceeds supply, she says.

In late January, Moderna asked FDA for permission to fill its vials with up to 15 doses to ease a bottleneck in manufacturing. Moderna and FDA told Science those discussions are ongoing; the change, if approved, would happen in the next 2 to 3months, the company said.

The waste of COVID-19 vaccine doses may not limit vaccinations of people in the United States much longer; President Joe Biden recently announced that doses will be available for all adults by the end of May. But many countries remain unable to secure enough COVID-19 vaccine to start mass vaccinations. The more efficient the United States can be in administering its supply, the more doses it may have left to share.

Griffin thinks the waste in the United States could have been avoided if the federal authorities had consulted front-line workers and public health experts earlier. Officials should have learned the importance of selecting the proper syringes from past influenza vaccination campaigns, he adds. “This all could have gone a lot smoother.”