Updated COVID-19 vaccine cuts risk of symptomatic infection by more than half, shows new data

The Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention has recommended an updated COVID-19 vaccination strategy for 2023–2024.

The new updated 2023-24 COVID-19 vaccine has shown that adults who received it were 54% less likely to have symptomatic infection than those who didn't.

This new approach published in the Morbidity and Mortality Weekly Report involves a monovalent XBB.1.5–derived vaccine was deemed crucial for individuals who were aged over 6 months to reduce the risks of COVID-19 in severe cases.

Throughout the fall of 2023, the XBB lineages shared the stage with JN.1 (an Omicron BA.2.86 lineage) that surfaced in September 2023. Both the variants carried amino acid substitutions raising concerns about their potentials to elude neutralizing antibodies. Despite the XBB lineages dominating until December 2023, JN.1 eventually took dominance in the US.

The identification of the S-gene target failure (SGTF) in real-time reverse transcription–polymerase chain reaction testing was found to a pivotal time-dependent indicator for JN.1 infection. After analyzing data from the Increasing Community Access to Testing SARS-CoV-2 pharmacy testing program, the study estimated the updated COVID-19 vaccine effectiveness (VE) against symptomatic SARS-CoV-2 infection by factoring in SGTF results.

Among the 9,222 eligible tests, the overall VE among adults aged ≥18 years stood at 54% (95% CI = 46%–60%) at a median of 52 days post-vaccination. In the subset of 2,199 tests incorporating SGTF testing, VE 60 to119 days after vaccination was 49% (95% CI = 19%–68%) for the SGTF-positive tests and 60% (95% CI = 35%–75%) for the SGTF-negative tests. In conclusion, the advisory committee advocated a broad approach for all individuals aged ≥6 months to receive an updated COVID-19 vaccine dose.

Reference:

Link-Gelles, R., Ciesla, A. A., Mak, J., Miller, J. D., Silk, B. J., Lambrou, A. S., Paden, C. R., Shirk, P., Britton, A., Smith, Z. R., & Fleming-Dutra, K. E. (2024). Early Estimates of Updated 2023–2024 (Monovalent XBB.1.5) COVID-19 Vaccine Effectiveness Against Symptomatic SARS-CoV-2 Infection Attributable to Co-Circulating Omicron Variants Among Immunocompetent Adults — Increasing Community Access to Testing Program, United States, September 2023–January 2024. In MMWR. Morbidity and Mortality Weekly Report (Vol. 73, Issue 4, pp. 77–83). Centers for Disease Control MMWR Office. https://doi.org/10.15585/mmwr.mm7304a2