Post by Nadica (She/Her) on Sept 5, 2024 0:08:58 GMT
RSV vaccine 75% effective against hospitalization in older adults, CDC study estimates - Published Sept 4, 2024
The respiratory syncytial virus (RSV) vaccine for older adults was 75% effective against hospitalization in its first season of use, adding to the findings of prelicensure trials, according to a test-negative, case-control analysis published today in JAMA.
Researchers from the US Centers for Disease Control and Prevention (CDC) and Vanderbilt University conducted interviews and examined the electronic medical records of 2,978 adults aged 60 and older hospitalized with an acute respiratory illness at 24 centers in 19 states participating in a surveillance network from October 2023 to March 2024.
Prelicensure trials left knowledge gaps
The 367 case-patients tested positive for RSV only, while the 2,611 control patients tested negative for RSV, COVID-19, and influenza. The median age was 72 years, the median Charlson Comorbidity Index score was 5 (considered high), and 24.2% had weakened immune systems (were immunocompromised).
In June 2023 the CDC recommended that all adults aged 60 and older receive the RSV vaccine based on the high vaccine effectiveness (VE) against RSV lower respiratory disease seen in prelicensure randomized trials. In a June 2024 update, the CDC recommended the vaccine for all adults aged 75 years and older and those 60 to 74 at high risk for severe RSV.
But the study authors noted that the prelicensure trials weren't powered to evaluate effectiveness against RSV hospitalization, didn't include immunocompromised patients, and underrepresented other populations at high risk for severe illness, including those aged 75 and older.
An estimated 60,000 to 160,000 RSV hospital admissions occur each year among US adults aged 65 years and older.
Just as effective in those 75 and older
In total, 2.5% of RSV patients and 9.8% of controls were vaccinated against RSV a median of 84 days before respiratory illness onset. Of the 288 RSV patients with known viral subtype, 72.9% had RSV B.
Relative to unvaccinated patients, vaccinated participants tended to be older (median age, 75 vs 72 years) and White (82.6% vs 60.7%). They were also more likely to have a weakened immune system (31.7% vs 23.4%), to have had outpatient visits in the past year (95.9% vs 90.1%), and to live in communities with a lower Social Vulnerability Index score (median, 0.37 vs 0.58).
VE against RSV-associated hospitalization was 75% (95% confidence interval [CI], 50% to 87%) and didn't differ when estimated with inverse probability of vaccination weighting (79% [95% CI, 56% to 90%]) or among adults 60 to 74 years old (75% [95% CI, 31% to 91%]) or 75 and older (76% [95% CI, 40% to 91%]).
The findings expand on prelicensure trial results by providing real-world evidence of vaccine protection against RSV hospitalization and demonstrating protection in a population at high risk for severe RSV, including adults aged 75 years and older and those with weakened immune systems, the researchers said.
"Evaluation of RSV VE in future seasons is important to confirm these findings and further examine VE among subgroups and by time since vaccination," they concluded.
Study link: jamanetwork.com/journals/jama/article-abstract/2823011
The respiratory syncytial virus (RSV) vaccine for older adults was 75% effective against hospitalization in its first season of use, adding to the findings of prelicensure trials, according to a test-negative, case-control analysis published today in JAMA.
Researchers from the US Centers for Disease Control and Prevention (CDC) and Vanderbilt University conducted interviews and examined the electronic medical records of 2,978 adults aged 60 and older hospitalized with an acute respiratory illness at 24 centers in 19 states participating in a surveillance network from October 2023 to March 2024.
Prelicensure trials left knowledge gaps
The 367 case-patients tested positive for RSV only, while the 2,611 control patients tested negative for RSV, COVID-19, and influenza. The median age was 72 years, the median Charlson Comorbidity Index score was 5 (considered high), and 24.2% had weakened immune systems (were immunocompromised).
In June 2023 the CDC recommended that all adults aged 60 and older receive the RSV vaccine based on the high vaccine effectiveness (VE) against RSV lower respiratory disease seen in prelicensure randomized trials. In a June 2024 update, the CDC recommended the vaccine for all adults aged 75 years and older and those 60 to 74 at high risk for severe RSV.
But the study authors noted that the prelicensure trials weren't powered to evaluate effectiveness against RSV hospitalization, didn't include immunocompromised patients, and underrepresented other populations at high risk for severe illness, including those aged 75 and older.
An estimated 60,000 to 160,000 RSV hospital admissions occur each year among US adults aged 65 years and older.
Just as effective in those 75 and older
In total, 2.5% of RSV patients and 9.8% of controls were vaccinated against RSV a median of 84 days before respiratory illness onset. Of the 288 RSV patients with known viral subtype, 72.9% had RSV B.
Relative to unvaccinated patients, vaccinated participants tended to be older (median age, 75 vs 72 years) and White (82.6% vs 60.7%). They were also more likely to have a weakened immune system (31.7% vs 23.4%), to have had outpatient visits in the past year (95.9% vs 90.1%), and to live in communities with a lower Social Vulnerability Index score (median, 0.37 vs 0.58).
VE against RSV-associated hospitalization was 75% (95% confidence interval [CI], 50% to 87%) and didn't differ when estimated with inverse probability of vaccination weighting (79% [95% CI, 56% to 90%]) or among adults 60 to 74 years old (75% [95% CI, 31% to 91%]) or 75 and older (76% [95% CI, 40% to 91%]).
The findings expand on prelicensure trial results by providing real-world evidence of vaccine protection against RSV hospitalization and demonstrating protection in a population at high risk for severe RSV, including adults aged 75 years and older and those with weakened immune systems, the researchers said.
"Evaluation of RSV VE in future seasons is important to confirm these findings and further examine VE among subgroups and by time since vaccination," they concluded.
Study link: jamanetwork.com/journals/jama/article-abstract/2823011