​SCIENCE FRIDAY: FLU; BRING ‘A’ & ‘B’ GAMES

Avoiding crowds at a Gulf beach at sunset. Taken by PKSenagore Feb 7, 2018. All rights reserved.

THE CDC REPORTS THAT INFLUENZA SEASONS can range from 11 to 20 weeks in duration. Currently the US is in week 10 (as of the most recent CDC update transcript from February 2, 2018). Tracking data has shown activity to be quite high and widespread, across 48 states (only Oregon has a slightly lower level of infection). The Influenza A strain H3N2 continues to dominate, but there are other viruses circulating including Influenza A H1N1 and Influenza B. 
 
Training for a spring race will be considerably set back after a bout of influenza viral illness. Of course, that’s not the worst-case scenario to be imagined, but it’s one that might cause runners and walkers who aren’t taking news reports of the infection seriously to take notice. And to continue to take or boost precautions to prevent becoming ill.
 
The media and public health messages remain the same: get vaccinated, wash your hands, stay home if sick, and cough/sneeze into the crook of your elbow as necessary so as not to spray the virus into the surrounding air. Seek medical care as indicated.
 
The bad news we’ve all heard is that even if you’ve gotten the vaccine, you may still contract the infection. If you’ve been sick in bed with influenza you might feel safe for the remainder of the flu season. Not so. You are susceptible to a second, different, influenza infection.
 
This post is a reminder NOT to let your guard down just yet.  For several reasons. The vaccines are not 100% effective against any of the strains. Protection provided by the vaccination immune response should be good for one year, but be aware that antibody levels wane as the months pass by, especially in persons over 65*.   Also, the influenza B strain included in the quadrivalent vaccine, B/Phuket/3073/2013-like (B/Yamagata lineage) virus, is not included in the trivalent vaccine.
 
A World Health Organization report about world-wide influenza activity indicated it “remained high in the temperate zone of the northern hemisphere” and that “influenza A accounted still for the majority of influenza detections but influenza B (mostly from the Yamagata lineage) increased in recent weeks.”
 
Thus, if you’ve received the 4-component vaccine you have some ‘B/Yamagata-lineage’ coverage that is likely not 100% effective. With the 3-component vaccine, you’ll have no ‘B/Yamagata-lineage’ coverage, and this infection is currently on the rise.
 
So, be prepared to bring both you’re “A’ and ‘B’ prevention games when it comes to influenza fighting.  If you’ve already been down with the ‘A’ flu you must still be vigilant. The extra care will pay off if you remain well and are able to train continuously for that first fun spring race. If you haven’t yet been vaccinated, do it, and opt for the 4-component, quadrivalent vaccine. If you received the trivalent type, a later quadrivalent vaccine is NOT recommended.
 
Also, be sure to get adequate sleep, eat a balanced diet, dress warmly when outdoors, and avoid crowds when possible.
 
RUN & MOVE HAPPY!

https://www.cdc.gov/media/releases/2018/t0202-flu-update-activity.html

https://www.cdc.gov/flu/about/season/flu-season-2017-2018.htm

http://www.who.int/influenza/surveillance_monitoring/updates/latest_update_GIP_surveillance/en/

IF YOU WISH to read in-depth vaccination advice approved by the CDC given to health care providers, check out this link: 
http://www.immunize.org/askexperts/experts_inf.asp

*NOTE:" Antibody to inactivated influenza vaccine declines in the months following vaccination. A study conducted during the 2011–12 influenza season (Euro Surveill 2013;18:20388) found a decline in vaccine effectiveness late in influenza season, primarily affecting persons age 65 years and older. While delaying vaccination might permit greater immunity later in the season, deferral could result in missed opportunities to vaccinate, as well as difficulties in vaccinating a large number of people within a more limited time period. Vaccination programs should balance maximizing the likelihood of persistence of vaccine-induced protection through the season with avoiding missed opportunities to vaccinate or vaccinating after influenza virus circulation begins.
Revaccination later in the season of people who have already been fully vaccinated is not recommended"
http://www.immunize.org/askexperts/experts_inf.asp