Common COVID Vaccine Administration Errors to Watch For

In December 2020, the US Food and Drug Administration approved Emergency Use Authorizations (EUAs) for the Pfizer-BioNTech and Moderna COVID-19 vaccines. As of March 20, 2021, more than 120 million COVID-19 vaccine doses have been administered to people in the United States. As we work toward expanding COVID-19 vaccination further, however, we must take care to minimize errors in vaccine administration.

Proper vaccine administration is necessary to ensure vaccine effectiveness, achieve optimal vaccine-induced protection, avoid safety implications, and assure confidence in the COVID-19 vaccination program. Since the launch of vaccination efforts on December 14, 2020, the Centers for Disease Control and Prevention (CDC) has received more than 300 inquiries through the CDC inquiry response services (eg, CDC-INFO, NIP-INFO) seeking guidance for managing an mRNA COVID-19 vaccine administration error that had occurred.

The most common error type described in inquiries (Table), representing more than one third of inquiries, was administration of a lower-than-authorized dose (eg, the needle disconnecting from the syringe, resulting in vaccine spillage). Other frequent error types queried included administration to someone younger than the authorized age (18.5% of inquiries) and administration by a route other than intramuscular (IM) (12.3% of inquiries).

These inquiries probably underestimate the actual number of COVID-19 vaccine administration errors and might not capture all inquiries CDC received.

Table. COVID-19 Vaccine Administration Error Inquiries Received by CDC, December 14, 2020, to February 28, 2021

Error type	Example	Number (%) of topics across inquires received (N = 324)^a
Administration by the incorrect route	Subcutaneous administration	40 (12.3%)
Administration at an incorrect anatomic site	Administration into shoulder bursa; administration in the gluteal muscle of the buttock	33 (10.2%)
Higher-than-authorized dose volume administered	Administration of undiluted vaccine	11 (3.4%)
Lower-than-authorized dose volume administered	Dose leaked out of syringe; recipient pulled away and dose leaked out	114 (35.2%)
Administration to someone younger than the authorized age	Administration to person aged < 16 years (Pfizer-BioNTech) or < 18 years (Moderna)	60 (18.5%)
Administration of a mixed-product series	First and second doses from different manufacturer	16 (4.9%)
Administration of a second dose earlier than the 4-day grace period	Second dose administered < 17 days (Pfizer-BioNTech) or < 24 days (Moderna) after the first dose	21 (6.5%)
Dose administered after improper storage and handling	Temperature excursion; more than allowed time after first vial puncture; use after beyond use date	15 (4.6%)
Other	Incorrect diluent; incorrect needle length; expired syringe	14 (4.3%)
^aSome inquiries represent errors affecting more than one vaccine recipient (eg, at a mass vaccination clinic).

The interim clinical considerations for the use of currently authorized COVID-19 vaccines contain guidance for managing vaccine administration errors. For most errors, CDC does not recommend repeating the dose. For dosage errors in which less than half the dose was administered, as well as errors in which only diluent was administered, CDC recommends repeating the dose as soon as possible in the opposite arm. CDC refers inquiries about errors related to improper storage and handling or use of an incorrect diluent to the vaccine manufacturer for guidance.

Errors Reducing Vaccine Effectiveness

Some vaccine administration errors might reduce vaccine effectiveness. Although data for mRNA COVID-19 vaccines are lacking, IM vaccine administration in general (compared with subcutaneous administration) optimizes immunogenicity and minimizes local adverse reactions. Subcutaneous fat has poor vascularity, leading to slow mobilization and antigen processing for some other vaccines administered subcutaneously.

When some vaccines (ie, hepatitis B, human papillomavirus, or influenza vaccines) are inadvertently administered subcutaneously, readministration by the IM route is recommended. However, it is not necessary to readminister vaccine doses intended for subcutaneous administration (eg, MMR or varicella vaccines) that were inadvertently administered by the IM route because immune response is unlikely to be affected.

Errors Affecting Safety

The safety implications of many COVID-19 vaccine administration errors remain unknown (eg, administration to someone younger than the authorized age or administration of a second dose earlier than the 4-day grace period). Shoulder injury related to vaccine administration (SIRVA) is a recognized consequence of unintentional injection of a vaccine into the tissues and structures lying underneath the deltoid muscle of the shoulder. It is an injury to the musculoskeletal structures of the shoulder, including ligaments, bursa, and tendons. SIRVA is thought to occur from unintended injection of vaccine or trauma from the needle into or around the underlying bursa of the shoulder.

Signs and symptoms of SIRVA include shoulder pain and decreased range of motion, hypothesized to be caused by an inflammatory reaction in the shoulder joint. SIRVA is preventable with correct recognition of anatomical landmarks and proper IM vaccine administration techniques.

As outlined in the EUA Fact Sheet for Healthcare Providers, vaccination providers are required to report vaccine administration errors — whether they are associated with an adverse event or not — to the Vaccine Adverse Event Reporting System. Vaccination providers should assess how the error occurred and take steps to prevent future errors.

Millions more doses of COVID-19 vaccines will be administered over the next few months. Although this report covers the time period when mRNA COVID-19 vaccines were administered, errors might occur with administration of other COVID-19 vaccine types, such as the newly authorized Janssen (Johnson & Johnson) viral vector vaccine.

Errors related to COVID-19 vaccine administration might result in reduced vaccine effectiveness and safety implications. A limited vaccine supply and strained vaccination provider workforce might preclude readministration of incorrectly administered doses. To prevent COVID-19 vaccine administration errors, providers should be aware of the EUA Fact Sheet for Healthcare Providers, Advisory Committee on Immunization Practices (ACIP) recommendations, and CDC's interim clinical considerations for COVID-19 vaccination (see the Resources section). Given the importance of vaccinating as many Americans as quickly and safely as possible, it is critical to prevent waste and make every dose count.