Pittsburgh, PA—As pharmacists work to vaccinate as many Americans as possible for this influenza season, a new study raises a question that could potentially change recommendations in future years.
The report published ahead of print by the journal Vaccine suggests that expanding the high-dose influenza vaccine recommendation to include middle-aged adults with chronic health conditions could be both cost-effective and life-saving.
Study authors, led by University of Pittsburgh School of Medicine researchers, call for clinical trials of the high-dose and new recombinant trivalent influenza vaccines in adults aged 50 to 64 years with chronic illnesses, such as heart or lung disease, diabetes, or cancer, to determine if those products provide better protection than the currently recommended standard-dose quadrivalent vaccine. The initial research used computer simulation.
“The growing proportion of middle-aged adults with chronic health conditions coupled with the modest effectiveness of the standard-dose influenza vaccine prompted us to explore whether existing vaccines already recommended for the elderly also could protect younger people,” explained lead author Jonathan Raviotta, MPH, CPH, senior research specialist with The Pittsburgh Vaccination Research Group (PittVax) at Pitt’s School of Medicine.
“Sure enough, expanding the recommendation does seem like a good policy—in silico. Before making such a recommendation, real world clinical trials are needed.”
While the high-dose influenza vaccine is recommended for adults aged more than 65 years because their immune response to the standard-dose vaccine diminishes with increasing age, it also is nearly double the price than the standard vaccine, according to the report.
So researchers sought to determine how cost-effective it would be to conduct large clinical trials of the vaccine in adults aged 50 to 64 years with chronic conditions. To do that, they employed the Influenza Decision Analysis model, developed by PittVax, to explore the cost effectiveness of alternate influenza vaccination scenarios.
Based on the best available data, the PittVax team reported that the high-dose vaccine would need to provide at least 18% more protection than the standard-dose vaccine to justify the increased cost per dose.
That could be plausible because previous clinical trials found an additional 24% effectiveness of high-dose vaccine over the standard-dose vaccine in the elderly. What remains unclear is whether the high-dose vaccine would be that much more effective in younger adults with high-risk medical conditions.
At the same time, study authors point out, a newer but even more expensive recombinant vaccine has shown an additional 41% protection among adults, suggesting that further research on vaccine options for high-risk, middle-aged adults might be justified.
Complicating research, the researchers note, is that circulating influenza strains can shift from season to season, and annual vaccine effectiveness can vary widely.
“Based on available data, using high-dose influenza vaccine or RIV in middle-aged, high-risk patients may be an economically favorable vaccination strategy with public health benefits,” they conclude. “Clinical trials of these vaccines in this population may be warranted.”
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