Atlanta—It might not have seemed like it at the height of the fierce influenza season this year, but pharmacists make a significant difference when they push influenza vaccines.

In an analysis of trends for the previous flu season, the CDC reports that flu activity in the U.S. during the 2016-2017 season began to increase in December and peaked in mid-February, with influenza A(H3N2) viruses predominating through mid-March. 

The A virus was predominant overall for the season, but influenza B viruses were more commonly reported from late March through May. 

As with the flu season that is waning now, hospitalization rates were high last year, especially among adults aged 50 to 64 years and 65 or older, the CDC notes. The situation was similar during two previous influenza A(H3N2)-predominant seasons—≥2012-2013 and 2014-2015, both of which had high severity among older adults, the agency writes.

During the 2016-2017 flu season, an estimated 30.9 million people in the U.S. became sick with influenza, 14.5 million visited a healthcare provider with those symptoms, and about 600,000 ended up in the hospital, public health officials calculate.

The CDC cautions, however, that it could have been much worse but that vaccinations prevented even higher rates.

Estimates suggest that influenza vaccination during the 2016-2017 influenza season prevented an estimated 5.29 million illnesses, 2.64 million medical visits, and 84,700 hospitalizations associated with influenza. 

Those with the least benefit were adults aged 18 to 49 years, who had the lowest vaccine coverage, and adults aged 65 years and older, who had higher vaccine coverage but the lowest vaccine effectiveness. On the other hand, vaccination prevented the greatest proportion of outcomes among children aged 6 months to 4 years and 5 to 17 years, where the burden of influenza illness and medical visits was high, and the vaccine effectiveness was greatest.

“Improvements in vaccine coverage could provide a greater public health benefit,” the CDC insists in its recent webpage update. “For example, if vaccination rates increased by just 5 percentage points across the entire population, another 483,000 illnesses, 232,000 medical visits, and 6,950 hospitalizations associated with influenza could be prevented. 

If vaccination rates improved to the Healthy People goal of 70% for all age groups, another 1.89 million illnesses, 822,000 medical visits, and 17,300 hospitalizations could have been prevented during the 2016-2017 influenza season.”

One key strategy to improve vaccine coverage is asking healthcare professionals to assess flu vaccine status at each encounter from October through May. Another important effort is to improve vaccination access through use of nontraditional settings, including pharmacies, workplaces, and schools, to reach those who might not visit a physician’s office during the influenza season.

At the same time, the CDC is seeking to improve vaccine effectiveness.

“In brief, higher vaccine effectiveness may be seen with different vaccine production methods or formulations, including higher doses of antigen or the addition of adjuvants to stimulate the immune response,” the CDC states.
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