mRNA and Protein Subunit COVID-19 Vaccine Reactogenicity and the Relationship to Productivity for Healthcare Workers and First Responders

Objectives: To compare the percentage of participants that experienced any solicited systemic reactogenicity symptom after one dose of the updated 2024–2025 adjuvanted protein-based Novavax (NVX; JN.1) or Pfizer–BioNTech mRNA (PFZ; KP.2) COVID-19 vaccine within 2- and 7-days post-vaccination and examine its disrupting impact on daily life. Methods: In this prospective, interventional, real-world study (SHIELD/ NCT06633835 ), previously vaccinated healthcare workers (HCWs) and first responders (FRs) from Salt Lake City, Utah, USA, and surrounding areas self-selected to receive NVX or PFZ. At 2- and 7-days post-vaccination, participants self-reported on 11 vaccine-related reactogenicity symptoms and functional impairment using a 5-item modified Sheehan Disability Scale. Results: 588 participants completed the Day 2 questionnaire (NVX, n=219; PFZ, n=369); 583 completed the Day 7 questionnaire (NVX, n=217; PFZ, n=366). Two-days post-vaccination, NVX recipients were less likely to report a systemic (OR=0.40; 95% CI, 0.21–0.75) or local (OR=0.10; 95% CI, 0.30–0.33) reactogenicity symptom and lost 50% fewer work hours (0.7 vs 1.4 h) and 66% fewer productive hours (0.8 vs 2.4 h) than PFZ recipients. There was little to no difference between vaccines at 7-days post-vaccination. Conclusion: Fewer reactogenicity symptoms following COVID-19 vaccination suggest use of the NVX vaccine as an immunization option with a lower disruption to daily life.