New Study Confirms Effectiveness of Updated COVID-19 Vaccines in Preventing Severe Illness and Death

Recent research involving multiple health systems across the United States, including the Regenstrief Institute and the CDC's VISION Network, has demonstrated the continued protection offered by the 2023–2024 COVID-19 vaccines. The comprehensive study assessed how well these updated vaccines defend against severe illness, hospitalization, and death during the waves dominated by the XBB and JN.1 Omicron subvariants.

Published in JAMA Network Open, the study analyzed data from over 345,000 emergency and urgent care visits, as well as more than 111,000 hospitalizations across 230 hospitals and 362 care centers nationwide. The findings indicate that the vaccines significantly reduce the risk of COVID-19 related health complications. During the first two months post-vaccination, protection against critical illness was observed to be as high as 68%, with an overall reduction in severe outcomes by nearly 50% within the first seven to 299 days.

While the efficacy of the vaccines against mild and moderate disease wanes over time, their effectiveness in preventing the most serious consequences remains strong, particularly in the initial months after vaccination. The study highlights that persons aged 65 and older, especially those with high-risk health conditions, benefit significantly from the updated vaccines, underscoring the importance of timely booster doses.

Researchers noted that vaccine effectiveness diminishes after six months, suggesting that booster shots might be necessary to maintain high-level protection. The study's collaborative effort included researchers from Kaiser Permanente Northwest, the University of Colorado, Intermountain Health, HealthPartners, and Kaiser Permanente Northern California, ensuring a diverse and comprehensive data set.

Associate editor Robert Egan emphasized that these findings reinforce the critical role of vaccination in safeguarding community health. Dr. Shaun Grannis from Regenstrief highlighted that despite evolving virus variants, updated vaccines remain vital in preventing severe COVID-19 outcomes and reducing healthcare burdens.

This research supports continued adherence to CDC vaccination recommendations, especially for vulnerable populations, to effectively combat COVID-19 and minimize hospitalizations and critical health events.