Older Seniors Need Flu Shots

H3N2 influenza viruses are dangerous to older people

old person's hand holding on a hospital bed rail

A new study published in the journal Open Forum Infectious Diseases (OFID) reports that people 85 years and older are much more likely to be hospitalized and die from an influenza virus than adults 65 to 74 years old. 

And, this Centers for Disease Control and Prevention (CDC) co-authored study confirmed that H3N2 flu viruses are particularly dangerous to older people. 

The researchers also found that the frequency of fever and several other typical symptoms of influenza decreased with age beyond 65 years, while the frequency of altered mental status increased with age. 

This OFID study adds to a growing body of evidence that supports the importance of vaccinating the 46 million adults (65+) and their contacts against influenza and Streptococcus pneumonia, and for the use of antiviral therapy as currently recommended by CDC.   

While flu seasons can vary in severity, during most seasons, people 65 years and older bear the greatest burden of severe flu disease.   

Approximately 90% of influenza-related deaths and 50-70% of influenza-related hospitalizations occur among people in this age group.   

Because of their increased risk, older adults are a priority group for vaccination.   

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The CDC says the prevalence of chronic diseases changes as age increases beyond 65 years, as does frailty and functional status.

Influenza news

This study looked at age-related differences in influenza-associated hospitalization rates, the clinical presentation of illness, and clinical outcomes among nearly 20,000 people older than 65 years who were hospitalized with laboratory-confirmed flu at 14 FluSurv-NET sites during the 2011-12 through 2014-15 influenza seasons, using 10-year age groups. 

Study results

  • Hospitalization rates among adults aged 85 years and older were 2-6 times greater than rates for adults aged 65-74 years.
  • The highest hospitalization rates occurred during H3N2 predominant seasons.
  • Patients aged 85 years and older had an increased risk of developing pneumonia and in-hospital death or transfer to hospice compared to hospitalized patients aged 65-74 years.
  • The frequency of fever and several other typical symptoms of influenza decreased in frequency with age beyond 65 years, underscoring the importance of flu testing and clinical discretion in rapid treatment in older adults.

Newer high-dose and adjuvanted influenza vaccines available for persons aged 65 years and older may provide additional protection among people in this age group. Flu vaccination has been shown to reduce flu illnesses and more serious flu outcomes including hospitalization or even death in older people. 

Based on the findings from this study, the CDC has begun presenting FluSurv-Net hospitalization data in finer age strata in older age groups to better inform public health prevention and response efforts.   

FluSurv-Net is an influenza hospitalization surveillance network that covers approximately 9% of the U.S. population, or about 27 million people, to estimate the burden of flu hospitalizations in the United States. 

The study is available online from Open Forum Infectious Diseases.