Okay, gang! It’s that time of year again. The kids are back in school, the weather is turning cooler, and soon, four strains of influenza virus (two A strains and two B strains) will begin making their rounds wherever people don’t cover their mouths and noses or wash their germ-covered hands (everywhere):

A/Michigan/45/2015 (H1N1)pdm09-like virus

A/Hong Kong/4801/2014 (H3N2)-like virus

B/Brisbane/60/2008-like virus (B/Victoria lineage)

B/Phuket/3073/2013-like virus (B/Yamagata lineage)


There are a lot of things your doctor can tell you about influenza with great confidence — most importantly, that epidemics are inevitable, it’s bad if you get it, and receiving a flu shot improves the odds of protecting yourself, your loved ones, people you work with, and total strangers like me. There are some things, however, that your doctor can’t predict:

> When will the flu season begin?  Some years, flu arrives in early fall; other years, it takes its sweet time to wreak havoc by early winter. Getting yourself and your children immunized before the end of October is the best bet for being protected the entire season.

> How severe will the disease be if I (or my children) come down with the flu?  Will this year’s flu season be just like last year’s “moderate” season (i.e. standard-horrible) or will it be worse? The answer may rest on how much pain and misery you can tolerate if you get the flu. Better to get a flu shot so you won’t find out.

> How long will the flu season last?  While flu seasons can fizzle out by February, mid-to-late spring (end of May) is more like it. We do know that the immunity acquired from a flu shot will last all season; a shot in August will protect the following June.

> Which influenza viruses will cause the most illness?  This varies year-to-year, although influenza A viruses typically circulate more prominently than influenza B viruses. Last season’s final tally consisted of both influenza A (78%) and influenza B (22%) strains. Most influenza A strains last year were of the H3N2 variety (97%). Most of the B strains that sickened people last year belonged to the B/Yamagata lineage. This year’s flu shot is the same as last year’s with one exception: A/Michigan (H1N1) replaces A/California (H1N1).

> Will circulating strains and vaccine strains match? Most people don’t realize just how good scientists have gotten over the years in their predictions, which are based on the evidence of strains circulating in the Southern Hemisphere while we in the Northern Hemisphere are enjoying our summer. (While we’re at it, let’s give it up for the scientific weather models and the meteorologists who so accurately predicted Hurricane Irma’s path and fury last weekend. Hats off!) What scientists cannot predict, however, is whether or not a strain will undergo a sudden mutation of its genome after the vaccine has already been manufactured. We saw such an “antigenic drift” in 2014-2015 , when the vaccine was only 23% effective that season.


Unfortunately, for the second straight year, intranasal administration of flu vaccine will not be available for young children and needle-phobes alike. Mary Elizabeth Dallas breaks the news:

Convenience was a main selling point for the nasal spray form of the flu vaccine, the researchers said. Parents often opted to give their child the nasal spray, viewing it as easier and less painful than the shot. Early on, studies suggested the nasal spray was also more effective for young children than the injection, the study authors noted.

By 2016, however, additional studies found the nose spray was actually less effective than the shot in preventing the H1N1 strain of influenza. These findings prompted the CDC to reverse its recommendation and advise against the nasal spray for the 2016-2017 flu season.


The American Academy of Pediatrics reminds us of some other things that can be predicted as we prepare for the 2017-2018 influenza season:

> The annual seasonal influenza vaccine is recommended for everyone 6 months and older, including children and adolescents, during the 2017–2018 influenza season.

> Vaccination remains the best available preventive measure against influenza.

> The number of seasonal influenza vaccine doses to be administered in the 2017–2018 influenza season depends on the child’s age at the time of the first administered dose and vaccine history.

  • Influenza vaccines are not licensed for administration to infants younger than 6 months;

  • Children 9 years and older need only 1 dose; and

  • Children 6 months through 8 years of age:

    • ∘ Need 2 doses if they have received fewer than 2 doses of any trivalent or quadrivalent influenza vaccine (IIV or LAIV4) before July 1, 2017. The interval between the 2 doses should be at least 4 weeks; and

    • ∘ Require only 1 dose if they have previously received 2 or more total doses of any trivalent or quadrivalent influenza vaccine (IIV or LAIV4) before July 1, 2017.

> Pediatric offices may choose to serve as an alternate venue for providing influenza vaccination for parents and other care providers of children, if the practice is acceptable to both pediatricians and the adults who are to be vaccinated. [Many Pediatric Alliance offices provide flu shots for parents.]

> Pregnant women may receive an influenza vaccine at any time during pregnancy.

> As soon as the seasonal influenza vaccine becomes available locally, pediatricians or vaccine administrators should [give it]…

> Providers may continue to offer vaccines until June 30 of each year, the date marking the end of the influenza season, because influenza is unpredictable.

> Antiviral medications are important in the control of influenza but are not a substitute for influenza vaccination. [It’s unlikely your pediatrician will prescribe antiviral medications for influenza unless your child, or those around her, are considered “high risk”.]


So give us a call, roll up your sleeve, and prevent an always-dreadful infection for yourself, your children, and people who, because of a medical contraindication, cannot receive the potentially life-saving intervention of a flu shot.

Don’t wait. Get your flu shot now!


The PediaBlog has covered influenza and its prevention many, many times here.


(Google Images)