Efficacy of NVX-CoV2373 in the US and Mexican adult population

Efficacy of NVX-CoV2373 in the US and Mexican adult population


Scientists have been working at a record speed to develop vaccines to contain the 2019 coronavirus disease pandemic (COVID-19), which has been caused by a new coronavirus, the severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2). Several vaccines against COVID-19, based on different technologies, have received emergency use authorization (US) from global regulatory bodies.

However, all available vaccines are designed to work against the SARS-CoV-2 ear protein of the original strain as an antigen.

Study: Efficacy and safety of NVX-CoV2373 in adults in the United States and Mexico. Image credit: rafapress / Shutterstock


Although all COVID-19 vaccines show a significant reduction in disease burden in clinical trials, the development of more effective vaccines is urgently required in the face of the emergence of more virulent and transmissible variants of SARS-CoV-2. , vaccine escape. -induced immune response as well as high global demand for vaccines.

A SARS-CoV-2 vaccine, NVX-CoV2373 (Novavax), has been developed using recombinant, prefusion, stabilized, and full-length spike protein trimers generated from the Wuhan-Hu sequence. -1. This designed spike protein was assembled into nanoparticles and co-formulated with a saponin-based adjuvant (Matrix-M). This vaccine has been reported to be stable at 2 to 8 ° C; therefore, it can be easily stored in the refrigerator. Scientists believe that this vaccine can effectively address the global problem of vaccine shortage and manage SARS-CoV-2 infection.

Previous studies have reported that NVX-CoV2373 is safe and immunogenic in adults. The current study showed that it provides high efficacy against the serious disease caused by B.1.351 (beta variant), in a phase 2b trial in South Africa. Similarly, this vaccine was found to be effective against severe infection caused by Alpha variants and was evaluated in phase three clinical trials in the United Kingdom.

A new study

A new study, published in New England Journal of Medicine, described the results of PREVENT-19 (Prefusion Protein Subunit Vaccine Efficacy Novavax Trial – COVID-19), a phase 3 trial of NVX-CoV2373 that included all adults in the United States and Mexico. This study was conducted during a period when circulating variants were predominantly Alpha, Beta, Gamma, B.1.427, and Epsilon and Iota.

Scientists have conducted a randomized controlled trial to determine the efficacy and safety of an adjuvanted SARS-CoV-2 recombinant protein vaccine in a study cohort consisting of approximately 30,000 participants from the United States and Mexico. Researchers continued to blindly assess the duration of protection and measured the overall safety profile of the vaccine among participants.

About the study

The current study revealed a high (90%) efficacy of the short-term vaccine of NVX-CoV2373 against COVID-19 infection and a 100% effectiveness in preventing moderate to severe disease. The researchers found that the vaccine was absolutely safe during a mean 2-month safety follow-up with mild to moderate transient reactogenicity. A long-term safety assessment of the vaccine is planned, meaning that participants would be monitored frequently 24 months after the initial vaccination.

The current trial also determines the efficacy of NVX-CoV2373 in the evolving pandemic. This vaccine showed a vaccine efficacy of over 90% against circulating variants in the United States and Mexico that are largely represented by the Alpha variant. The results of this study are in line with the phase three trials conducted in the UK which reported 86.3% vaccine efficacy. In addition, this vaccine showed great efficacy against other variants of SARS-CoV-2 that have not been classified as variants of interest or variants of concern and that were more closely related to the original strain of SARS-CoV-2. 2. This study also indicates that the vaccine is effective against a wide range of variants beyond the prototype strain.

It is important to note that this study includes the demographic diversity of the trial population and therefore indicates the effectiveness of the vaccine between different races and ethnic minorities. Among the different demographic groups, the effectiveness of NVX-CoV2373 among the Hispanic or Latino population in the United States was found to be lower compared to other demographic groups. This may be due to an unidentified host or a viral factor. A similar finding has been reported for another vaccine against COVID-19; however, the reason for this finding has not yet been addressed.


This study includes several limitations, for example, the exclusion of participants from older age groups, and therefore the estimate of vaccine efficacy in this group was unknown. However, NVX-CoV2373 UK Phase Three Clinical Trials included participants over the age of 65 and reported a vaccine efficacy of 88.9%, which is comparable to estimates associated with younger age. Another limitation of this study is the disproportionate number of non-blind requests from trial participants in the early stages of the trial, which resulted in the exclusion of a large number of control group participants. placebo.

Although the follow-up period had been limited to around three months, it had been consistent with the period required for the emergency use permit. The overall effectiveness of this vaccine has been reported to be high, regardless of the circulating strain. However, the authors have proposed long-term safety, blind crossover, and hazard models for future studies to further validate the efficacy and safety of NVX-CoV2373.



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