Injection Site Necrosis Associated With Pneumococcal Vaccine

The Vaccine Adverse Event Reporting System (VAERS) system is a passive surveillance system that allows individuals to report adverse events of vaccines they have had administered. As the general public can self-report, follow-up investigations are needed to address these adverse events and confirm complaints.

VAERS is one way in which the FDA and CDC can monitor vaccines post-marketing.

A new study published in JAMA Internal Medicine looked at VAERS events related to the pneumococcal vaccine. Back in 2020, the FDA detected a safety signal of injection site necrosis after taking the 23-valent pneumococcal vaccine (Pneumovax 23; Merck).

The investigators reviewed reports, including submitted medical records, clinician notes, and pathology reports, and they defined cases using adapted criteria for a local reaction at or near the injection site. They calculated a reporting rate using vaccine distribution data from the manufacturer.

The study investigators looked at 104 VAERS complaints of skin necrosis. Of them, 48 reports met their case definition.

“Of these cases, most were for skin necrosis (n = 43), 5 of which also included fat necrosis. The remaining cases were necrosis of fascia (n = 2); fat and fascia (n = 1); fat, fascia, and muscle (n = 1); and muscle (n = 1),” the investigators wrote. “One-half of the 48 cases were reported from foreign countries and one-half were from the US. In 23 cases (47.9%), the reactions were serious, including 1 fatality (unrelated to vaccination). Seventeen patients (35.4%) required hospitalization, and 26 (54.2%) required surgical intervention, most commonly debridement. Eight patients (16.7%) underwent multiple surgical procedures, and 3 (6.3%) required a skin graft.”

According to the investigators, the injection site necrosis reporting rate was less than 0.2 cases per million vaccine doses distributed. They also did a search of the literature which showed 2 cases of injection site necrosis after the 23-valent pneumococcal vaccine.

The investigators noted an update to the vaccine packaging as well as its overall safety profile. “The Pneumovax 23 US package insert has been updated to include injection site necrosis in section 6.2, Post-Marketing Experience. The overall benefit-risk balance for this vaccine remains favorable.”