Flu Vaccine a Closer Match, Time to Get Vaccinated, CDC Says

Alicia Ault

September 17, 2015

Led by Centers for Disease Control and Prevention (CDC) Director Tom Frieden, MD, a host of healthcare organizations issued an annual plea today for influenza vaccination for everyone aged over 6 months, noting that this year's vaccine would be a closer match for the H3N2 strain still circulating from last year.

At a media briefing, Dr Frieden rolled up his sleeve and received a shot that was captured by dozens of video cameras and smartphones. He noted that just under half of all Americans eligible were vaccinated for influenza last year, and that rates were highest for children aged 6 to 23 months (75%) and 2 to 4 years (68%), and for adults aged over 65 years (67%). But vaccination rates are lagging among 18- to 64-year-olds, hovering below 40%.

"We need to get more young and middle-aged people vaccinated," said Dr Frieden. He said officials were hopeful, given "increasing opportunities for vaccination," including at pharmacies, urgent care centers, and workplaces.

Dr Frieden also discussed data just issued by the CDC on vaccination coverage during the 2014-2015 flu season for pregnant women and healthcare professionals. Only about half of pregnant women were vaccinated, similar to the 2013-2014 flu season ( MMWR. 2015;64:1000-1015). Overall, just over 77% of healthcare workers were vaccinated, similar to the 75% who received a shot in the previous flu season. But there are still significant gaps, especially among providers working in long-term-care settings, where only 64% were vaccinated in 2014-2015.

A Closer Match

The 2014-2015 vaccine was ineffective against the predominant A strain that was circulating, A/Switzerland/9715293/2013-like virus (H3N2). The H3N2 strains are associated with worse illness and higher mortality. Not surprisingly, the rate of flu-related hospitalizations among people aged 65 years or older was the highest recorded in the 10 years since the CDC began tracking that measure. The H3N2 strain also hit children hard. The agency reported 145 lab-confirmed pediatric influenza deaths, which is likely an underestimate, said the CDC.

Dr Frieden said that the 2015-2016 flu vaccine would more closely match that H3N2 strain, which, according to the latest surveillance data, continues to circulate. Manufacturers have prepared 171 million doses of influenza vaccine, of which 40 million have already been distributed, he said.

The CDC director urged Americans to get vaccinated this year, despite the low effectiveness of the 2014-2015 vaccine.

"Even in a year when the flu virus isn't well matched, it remains the single best thing you can do to protect you, your family, and your community against influenza," he said.

Progress in Health Workers

Though overall vaccination rates in healthcare workers were similar the last two flu seasons, they are up almost 14% from the 2010-2011 season, according to the CDC.

Coverage in 2014-2015 was highest among pharmacists, at 95%, followed by physicians and nurses, at 89%. Nurse practitioners and physician assistants had 87% coverage. The lowest rates were among assistants and aides, at 64%.

Healthcare workers who were required to be vaccinated by their employer had the highest rates (96%), and for those who were not required, rates got a boost when vaccination was offered on-site at no cost, especially if offered on more than one day (74%-84%). But vaccination rates slipped to 44% for settings where the vaccine was not required, promoted, or offered on site, said the CDC.

The agency is reaching out to ensure greater health worker coverage, especially in nursing homes and other long-term-care settings, Daniel Jernigan, MD, director of the CDC's Influenza Division, told Medscape Medical News.

"We really encourage those systems that run long term care facilities and the physicians that are over those systems to really encourage their staff to get vaccinated," he said.

Overall, though, the vaccination uptick among healthcare workers is worth noting, said William Schaffner, MD, medical director of the National Foundation for Infectious Diseases and professor of preventive medicine and infectious diseases at Vanderbilt University School of Medicine in Nashville, Tennessee.

"It's a growing success story," Dr Schaffner told Medscape Medical News.

Dr Schaffner said he expects more coverage especially as state and local regulatory agencies are increasingly focusing on immunization of healthcare workers.


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