Recombinant Flu Shots Can Prevent Additional Hospital Stays

TOPLINE:

A recent analysis indicated that switching from the standard-dose inactivated influenza vaccine to the recombinant influenza vaccine (RIV) could have prevented nearly 100,000 hospitalizations among working-age adults in the United States over 10 seasons. The greatest benefits would have been seen in individuals aged 50-64 years and at-risk adults aged 18-49 years with chronic conditions.

METHODOLOGY:

• Researchers investigated the burden of influenza and the potential impact of switching from the standard-dose inactivated influenza vaccine to RIV in reducing influenza-related hospitalizations among working-age adults in the United States, including those aged 18-49 years or 50-64 years.
• They collected data on influenza burden, vaccine effectiveness, and coverage rates for both age groups from the US Centers for Disease Control and Prevention for the years 2012-2023, excluding 2020-2021.
• The rates of influenza-related hospitalizations and deaths were estimated among adults aged 18-49 years or 50-64 years with at least one chronic medical condition.
• A modeling analysis was carried out for both age groups to estimate the potential reduction in hospitalizations if RIV had replaced the standard-dose inactivated influenza vaccine, taking chronic conditions into account.

TAKEAWAY:

• Over the past decade, influenza caused a median annual number of 151,021 hospitalizations and 7215 deaths among US adults of working age, with adults aged 50-64 years experiencing threefold and fivefold higher rates of hospitalizations and deaths, respectively, than those aged 18-49 years.
• Among adults aged 18-49 years, the 14% with chronic conditions accounted for 28% of hospitalizations and 29% of deaths related to influenza. Similarly, among those aged 50-64 years, the 47% with at least one chronic condition accounted for 68% of hospitalizations and 69% of deaths related to influenza.
• The modelling analysis indicated that a complete switch to RIV could have prevented a total of 87,654 (95% CI, 74,518-101,482) additional influenza-related hospitalizations over the past ten seasons among adults aged 50-64 years.
• Similarly, among adults aged 18-49 years, a switch to RIV could have prevented a total of 14,436 (95% CI, 10,100-19,963) additional influenza-related hospitalizations over the same period.

IN PRACTICE:

“Considering the whole 50- to 64-year age group for the use of enhanced vaccines, like RIV, deserves consideration as it could support public health interventions promoting healthy aging,” the authors wrote. “A risk-based recommendation may be more appropriate for younger working ages, given the fraction of burden within those with chronic conditions,” they added.

SOURCE:

The study was led by Laurence Torcel-Pagnon, MSc, Sanofi, Lyon, France. It was published online on April 17, 2025, in Clinical Infectious Diseases.

LIMITATIONS:

The vaccine effectiveness of RIV vs the standard-dose inactivated influenza vaccinevaries between seasons and studies, making it challenging to compare benefits across different scenarios. The analysis was limited due to a scarcity of high-quality evidence on clinical burden and vaccine effectiveness in at-risk groups. Lastly, the modeling approach used may not have considered indirect effects that influenced vaccination at the population level.

DISCLOSURES:

This study was funded by Sanofi. The authors reported being employees of Sanofi and potentially holding shares in the company. 

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.