The rollout of the Covid-19 vaccination program has reached new heights of complexity with the start of the bivalent booster program, leading to concerns about the potential for more errors in the administration of vaccines.
Even before the addition of the new booster shots, more than 5,300 errors in vaccine dose delivery in children alone were reported, according to data from the Centers for Disease Control and Prevention. Those errors included giving the wrong dose or the wrong product for a recipient’s age, using undiluted vaccine when dilution was called for, or administering vaccine that was past its expiration date.
The CDC says that there’s no evidence so far that these administration errors have triggered more severe adverse events than are normally reported in children who have been given the correct doses of these products. But everyone involved in this effort understands that vaccine administration errors undermine the confidence of the people delivering vaccine, the people who received the wrong dose and, if those people are children, their parents.
“I just honestly feel terrible about the fact that there are so many administration errors that seem disproportionate to what we’ve seen with other vaccines or with the adult [Covid] vaccines,” Grace Lee, chair of the Advisory Committee on Immunization Practices, said during a recent meeting at which some updated figures on adverse events in children were presented.
At that Sept. 1 meeting, Lee and other members of the ACIP — an expert panel that advises the CDC on vaccine policy — voiced serious concerns about the challenges of keeping as many as 11 different brands and formulations of vaccine straight as doctors offices, clinics, and pharmacies across the country give a primary series to young children, regular booster shots to older children, and new two-strains-in one or bivalent boosters for people over the age of 12.
When people administering Covid vaccines make an error, they are required to report it to VAERS, the vaccine adverse events reporting system run by the Food and Drug Administration and the CDC.
The current Covid vaccine schedule seems tailor-made to trip up people who are delivering the doses, with multiple vaccines that are administered in different volumes, some after dilution but many not, and with intervals between doses ranging from three weeks to several months.
“This immunization schedule is among the most complex that I’ve personally had to deal with, and it is constantly changing,” Lee, the associate chief medical officer for practice innovation at Lucile Packard Children’s Hospital in Palo Alto, Calif., said in an interview.
The CDC understands the potential for mistakes is real and has produced visual guides for vaccinators. It is also developing strategies to try to minimize the risk that a person will get the wrong formulation, Elisha Hall, clinical guidelines lead for CDC’s Covid-19 vaccine policy unit, told STAT.
“We’re definitely concerned that this presents more opportunities for errors, because there’s more vials. The labels are similar. So what we’re really trying to do is help providers navigate this situation by coordinating with partners, to provide proactive education and messaging for health care providers about the products available and the strategies they could put in place to mitigate errors,” she said.
Chief among their concerns: that people, especially children, will inadvertently be given the wrong doses. Too little, and they may not be protected. Too much and vaccine-induced side effects could be unpleasant.
“For the most part I think the error we would be most concerned about potentially leading to adverse reactions would be a higher-than-authorized dose — getting much more vaccine than they should be getting,” Hall said.
This has happened. A quick search through the VAERS database pulls up reports of toddlers being given 10 times the amount of vaccine they were meant to get. In at least one report, a child under the age of 2 was given the full contents of a 10-dose vial in error. The mother reportedly said the child had no adverse reaction to the vaccine.
Four brands of Covid vaccines have either been approved or authorized for use in this country: the ones made by the partnership of Pfizer and BioNTech, Moderna, Janssen (a subsidiary of Johnson & Johnson), and Novavax. The Janssen vaccine, which the FDA said should only be used by people who cannot take one of the other options, is likely rarely employed at this point. And to date, the Novavax vaccine has not been authorized for use as a booster shot, so it comes in a single formulation.
Pfizer has a bivalent booster for people 12 and older, and a monovalent primary series for people in the same age bracket. Both come in vials bearing gray caps. How to tell the difference between the two? Two lines of text on the vial label, identifying the bivalent vaccine as targeting the original SARS-CoV-2 virus and an Omicron BA.4/BA.5 strain.
The company also has different formulations for children aged 6 months to 4 years and 5 to 11 years; the former comes in vials bearing maroon caps, the latter orange caps. The vaccine in these two formulations must be diluted before use, a step not needed for Pfizer’s adult formulation, or for any of the Moderna products.
Meanwhile, Moderna’s new bivalent booster is distributed in vials with dark blue caps, as is the company’s product for children aged 6 to 11. Though the vial labels are bordered in gray for the bivalent booster and purple for the monovalent product for 6- to 11-year-olds, the potential for confusion exists, Hall said. “It does look pretty similar.”
The different brands have differing intervals between doses, depending on the age of the recipient and whether the individual is immunocompromised or not. For example, children under the age of 5 who are immunocompromised can get three doses of Moderna vaccine with an interval of four weeks between each dose, or three doses of Pfizer with a three-week interval between dose 1 and dose 2, but an interval of at least eight weeks between dose 2 and dose 3.
If all that isn’t enough, expiration dates on the labels of vaccines are not always accurate; in some cases, the expiration dates were changed — lengthened — after the labels were printed and affixed to the vials. If a vial appears to contain expired vaccine, an online check of the vial’s bar code needs to be run to determine if it can be used or must be discarded.
“These vaccines are the most complex to manage,” Lee said after running through a dizzying list of things that could trip up people administering these vaccines. “From my perspective especially, I think about a solo practitioner in a very busy clinic, just trying to get through the day and try to figure out which vaccine is the right one to give this kid.”
Suzanne Berman is in a situation much like the one Lee worries about. Berman is a pediatrician in Crossville, Tenn., running a small practice she owns with her husband; they employ a handful of other doctors. Theirs is the only pediatric practice in their county that offers Covid vaccines.
Delivering Covid vaccines is definitely “tricky,” she admitted, though she noted pediatricians have a lot of experience with complicated vaccine schedules and fridges full of vaccine vials.
“This has totally supersized the complexity, but in pediatrics we were already prone to be very careful and develop systems in place for training and spot checking and auditing to make sure that this is happening correctly,” said Berman, who is chair of a committee representing the interests of small, independent medical practices that are members of the American Academy of Pediatrics.
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To cut down on the risk of administration errors, Berman’s practice decided to only stock one brand of Covid vaccine, Pfizer. A friend who is also a pediatrician elsewhere chose to only offer Moderna, she said.
“Just that, just limiting what you have in your fridge, is very helpful at cutting down on potential errors,” said Berman.
Another tool her practice uses plays off the color-coded vial caps. They store vials in different colored refrigerator bins and put loaded syringes into corresponding colored baskets. “So basically it’s a riot of color. It looks like Mardi Gras,” she said. “We try to make it visually easy for our busy nurses by adding that color dimension.”
Elizabeth Haftel, pharmacy vaccine coordinator at Boston’s Beth Israel Deaconess Medical Center, said there are a variety of strategies people use to try to lower the risk of vaccination errors. Some store vials of primary series vaccines and those containing booster doses in different fridges. Or on different shelves in a fridge.
“And you know, labeling is everything in pharmacy,” Haftel said. “Everything should be labeled when it’s drawn up in a syringe. Every dose should have a label on it stating whether it’s a bivalent, a monovalent, which brand it is … as well as the volume.”
Another technique some practices are resorting to involves giving vaccines to different populations on different days. Adults only on Wednesday, say, with pediatric shots offered on Fridays. The approach is helpful for staff administering vaccines, but perhaps less so for families hoping to get multiple shots or boosters in one visit.
The CDC is urging people delivering vaccines to triple check all their steps.
Melody Butler, the executive director of a group called Nurses Who Vaccinate, said vaccine providers who are diligent and organized know how to handle tasks like these. “It comes down to nursing basics,” said Butler, who added that slowing things down is important. “When steps are skipped, mistakes are made.”
