Protein-based COVID-19 Vaccine Reports Few Adverse Events

The U.S. CDC published a Morbidity and Mortality Weekly Report (MMWR) that concluded post-authorization safety data after receipt of a primary Novavax COVID-19 vaccine dose is limited by the low number of doses administered (0.01% of total COVID-19 vaccines administered), available data are consistent with those from preauthorization clinical trials.

And no new safety concerns were identified, wrote the CDC on August 4, 2023.

This MMWR stated from July 13, 2022–March 13, 2023, a total of 69,227 Novavax doses were administered to persons in the U.S., and 230 reports of adverse events after vaccination were received by the Vaccine Adverse Event Reporting System (VAERS).

Among the 230 reports received, 19 (8.3%) were classified as serious, and no deaths were reported after vaccination.

Serious reports included one case of thrombosis, two of pericarditis, one of Guillain-Barré syndrome, and two of seizure.

The remaining serious reports described chest pain, arrhythmia, sickness, hospitalization, adverse event not otherwise specified, balance disorder, peripheral neuropathy aggravated, and vaccine failure. 

Limitations of this analysis include reporting biases and inconsistency in the quality and completeness of reports to VAERS.

Furthermore, VAERS data generally cannot be used to determine whether a vaccine caused an adverse event.

In addition, approximately one-half of the reports representing adverse events of special interest lacked medical records for CDC review.

Novavax COVID-19 Vaccine Adjuvanted (Nuvaxovid™, CovoVax™, NVX-CoV2373) was the first protein-based vaccine engineered from the genetic sequence of the SARS-CoV-2 beta coronavirus.