Atlanta—Influenza vaccines pushed by pharmacists all season have a relatively high rate of effectiveness, unlike last year.
The CDC reports a preliminary overall influenza vaccine effectiveness (VE) of 59% percent this season. That compares to about 23% last flu season, although it is more in line with previous years. VE has been as high as 60% in 2010-2011 to as low as 21% in 2005-2006, according to CDC estimates.
The VE data was presented recently at a meeting of the agency’s Advisory Committee for Immunization Practices (ACIP) in Atlanta.
“This means that getting a flu vaccine this season reduced the risk of having to go to the doctor because of flu by nearly 60%,” said Joseph Bresee, MD, chief of CDC’s Epidemiology and Prevention Branch. “It’s good news and underscores the importance and the benefit of both annual and ongoing vaccination efforts this season.”
Specifically, according to the CDC, vaccine effectiveness was:
• 51% against the H1N1 viruses responsible for most flu illness this season,
• 76% against all influenza B viruses, and
• 79% against the B/Yamagata lineage of B viruses
Public health officials said there was not enough data yet to estimate VE by age group, nor to estimate VE against H3N2 viruses or B/Victoria lineage viruses.
Influenza-like illness levels and the numbers of influenza-positive laboratory tests rose the week ending January 16 this year, with activity elevated for 5 consecutive weeks at the time of the report. The CDC noted that, for the past 13 seasons, flu seasons have averaged 13 weeks in length, with a low of 1 week to a high of 20 weeks.
“Flu activity this season started a bit later and has been lower so far than we’ve seen during the previous three seasons, but activity is still on the upswing and expected to continue for several weeks,” Bresee explained. “Flu causes serious illnesses and deaths every year. This season, CDC has received reports of hospitalizations and deaths in young, otherwise healthy people who were infected with influenza A H1N1, but not vaccinated.”
Interim estimates are based on data collected from the U.S. Flu VE Network from November 2, 2015, through February 12, 2016 and are likely to change with weeks to go for the current flu season.
Also at the recent ACIP meeting, the committee renewed the universal recommendation, in place for 6 years, for influenza vaccination for everyone older than 6 months. It also amended language related to flu vaccine recommendations for egg-allergic patients so that they may now receive the live attenuated influenza vaccine (LAIV).
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