ESCMID: Sanofi's Nuvaxovid COVID-19 vaccine showed better tolerability than mNEXSPIKE in head-to-head study

ESCMID: Sanofi's Nuvaxovid COVID-19 vaccine showed better tolerability than mNEXSPIKE in head-to-head study

• First head-to-head, double-blind, randomized phase 4 study powered to directly compare the tolerability profiles of these vaccines in adults in a real-world setting
• Results were presented today at the European Society of Clinical Microbiology and Infectious Diseases Global Congress in Munich, Germany.

Paris, April 18, 2026. Sanofi's protein-based non-mRNA COVID-19 vaccine Nuvaxovid (NVX-CoV2705) demonstrated statistically significant lower systemic reactogenicity (the expected side effects that might occur following vaccination) compared to mNEXSPIKE (mRNA-1283), Moderna's latest mRNA COVID-19 vaccine, across all pre-specified endpoints in the COMPARE study. The randomized, double-blind study, which enrolled 1,000 adults in the US, was presented at the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Global Congress in Munich, Germany.

These results address a persistent challenge: despite the end of the pandemic, COVID-19 continues to cause significant hospitalizations and deaths globally, while placing considerable strain on health systems during seasonal peaks. Yet vaccination uptake remains low, with concerns about vaccine side effects ranking among the top reasons cited by adults for not getting vaccinated against COVID-19.

In the COMPARE study, when side effects did occur with Nuvaxovid, they were less severe and shorter in duration compared to mNEXSPIKE. Severe systemic symptoms (body-wide reactions such as fatigue, headache, or fever) that prevent people from carrying out their normal daily activities were more than 50% less frequent with Nuvaxovid, affecting fewer than one in ten Nuvaxovid recipients compared to one in five mNEXSPIKE recipients, an analysis of the data showed. Severe local symptoms (reactions at the injection site such as pain, redness, or swelling) with Nuvaxovid were rare, and more than 75% less frequent compared to mNEXSPIKE. This was reflected in the study participants' own experience: those who received Nuvaxovid were nearly twice as likely as mNEXSPIKE recipients to say they would definitely choose the same vaccine type again the following year.