by Diana Kwan, Pharm.D., USP Senior Scientist II for Healthcare Quality and Safety
Vaccine mix-ups have received national focus in recent months after the FDA granted Pfizer-BioNTech an Emergency Use Authorization for children 5-11 years of age on October 29, 2021.1,2,3 Varieties of vaccine mix-up incidents have previously been reported, for example, with patients receiving the COVID-19 vaccine instead of the flu vaccine and vice versa. Now with the expansion of eligibility into the pediatric population combined with the Omicron variant spurring more people to get vaccinated, USP has updated its COVID-19 Vaccine Handling Toolkit to include information on how to prevent vaccine mix-ups.4
Reported vaccine mix-ups have been attributed to syringes near each other, unlabeled syringes, distractions, staffing shortages, and labeling confusion. Presently, Pfizer-BioNTech distinguishes its three formulations of COVID-19 vaccines by the color of the vial cap and label border:
- Purple Vial Cap and Label Border (must dilute) for 12 years and older (final diluted conc: 30 mcg/ 0.3 mL)
- Orange Vial Cap and Label Border (must dilute) for 5 through 11 years (final diluted conc: 10 mcg/ 0.2 mL)
- Gray Vial Cap and Label Border (no dilution) for 12 years and older (final conc: 30 mcg/ 0.3 mL) –not yet available in US
However, the Institute for Safe Medication Practices (ISMP) states, “While different color caps might help prevent some mix-ups, once the cap is removed and discarded, doses may be prepared one at a time rather than all at once, which will render the cap color irrelevant.”5 Another fact worth noting regarding the pediatric formulation labeling is that the marking “Age 5y to <12 y,” is not as prominent as “DILUTE PRIOR TO USE” in red.6
Although mix-ups appear to be rare, these errors in vaccine administration can have serious consequences to patients, including lack of proper protection from a disease, the need to revaccinate, diminished trust in vaccines, and increased healthcare costs. Also, it is reasonable to assume that these mix-ups will occur on a larger scale as pediatric doses become more widely available internationally.
The revision of the USP COVID-19 Vaccine Handling Toolkit in November includes information on the new Pfizer-BioNTech COVID-19 formulations and how to prevent vaccine mix-ups based on learnings from ISMP’s National Vaccine Errors Reporting Program (VERP). The methods in the toolkit include placing different vaccines in different areas, such as separate plastic bins, asking the patient/caregiver to read the syringe label (and vial if present) aloud to confirm the correct vaccine prior to administration, and other recommendations.
There are safety practices and vaccination processes that can be performed by healthcare practitioners in clinics and pharmacies administering adult and pediatric COVID-19 vaccines to minimize human error and help ensure vaccines work as intended. For more information on USP’s work with quality standards for vaccines, and our response to the COVID-19 crisis, visit https://www.usp.org/covid-19.