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High-dose flu vaccine more effective than standard vaccines in older adults

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February 22, 2019

Yinong Young-Xu, ScD
Yinong Young-Xu

Compared with standard-dose influenza vaccines, the high-dose vaccine is more effective in preventing influenza- or pneumonia-associated hospitalizations, cardiorespiratory hospitalizations, and all-cause hospitalizations among adults aged 65 and older, data from around 1.7 million patients showed.

“This long-term analysis across five flu seasons — 2010-2011 through 2014-2015 — provides a succinct appraisal of the high-dose vaccine’s effectiveness over the standard-dose vaccine,” Yinong Young-Xu, ScD, director of the clinical epidemiology program at the VA Medical Center in White River Junction, Vermont, told Infectious Disease News.

During the 2017-2018 season, 48.8 million illnesses, 22.7 million medical visits, 959,000 hospitalizations and 79,400 deaths were caused by influenza, according to the CDC. This season has been less severe. However, the vaccine has demonstrated just 24% effectiveness in adults aged 50 or older.

Recently reported study results showed that vaccination halves the risk for influenza-related hospitalization among adults, and many other studies have shown the benefits of influenza vaccination in older adults. Adding to this body of literature, Young-Xu and colleagues’ study assessed the relative vaccine effectiveness of the high-dose influenza vaccine compared with the standard dose in preventing hospitalizations among Veterans Health Administration (VHA)-enrolled veterans aged 65 years or older.

According to the study, the researchers collected electronic medical record databases in the VHA and Medicare administration files for five influenza seasons from 2010-2011 to 2014-2015. The analysis included 3,638,924 person–influenza seasons of observation. Of these, 4% were among individuals who received the high-dose vaccine and 96% were among those who received the standard-dose vaccine.

A longitudinal analysis of all five seasons revealed that the high-dose vaccine had an estimated 10% (95% CI, 8%-12%) instrumental variable-adjusted relative vaccine effectiveness — or additional reduction — in all-cause hospitalization compared with the standard dose. The high-dose vaccine also demonstrated 18% (95% CI, 15%-21%) and 14% (95% CI, 6%–22%) relative vaccine effectiveness against cardiorespiratory-associated hospitalization and influenza/pneumonia-associated hospitalization, respectively, according to the results.

The researchers observed similar findings when they assessed the vaccine effectiveness by season.

“Overall, the high-dose vaccine was found to be more effective than standard-dose vaccines in preventing hospitalizations caused by the flu, pneumonia, cardiorespiratory conditions and all-cause hospitalizations,” Young-Xu said. “The high-dose flu vaccine can help protect adults 65 years of age and older from serious illness and complications related to the flu.” – by Marley Ghizzone

Disclosures: Young-Xu reports receiving research funding from Sanofi-Pasteur. Please see the study for all other authors’ relevant financial disclosures.

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