ECDC Systematic Review: Efficacy, Effectiveness & Safety of Newer & Enhanced Seasonal Influenza Vaccines

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Although I get the flu shot every year and recommend it to others, I do so with the knowledge that most years the flu shot only provides a moderate level of protection against the flu, and some years - and for some people - it may provide little or no protection at all. 

Despite some technological advances, we are still creating flu vaccines pretty much the way we've been doing it for 70 years.

 

Twice each year experts try to anticipate what flu strains will dominate in the northern and southern hemisphere 6 to 12 months in advance (see WHO Recommended 2021 Southern Hemisphere Flu Vaccine Composition), and then the vaccine requires up to 6 months to produce and distribute.  

Like wearing a seat belt every time you ride in a car, getting the flu shot can't guarantee you'll come away unscathed . . . but it does increase your chances.  But as I grow older, I can use all the extra protection I can get. 

The `holy grail' of a universal flu vaccine - one that targets a wider range of flu viruses - remains elusive, although progress is being made.  Despite a full court press by the NIH - and many other scientific institutions over the past 15 years - we still appear to be 5 or more years away from having a `universal' flu vaccine.

A universal flu vaccine is often described in the popular press as being a `one time (or every few years) shot' that would convey nearly full protection against all flu sub-types.  While ideal, the current goal is a bit more modest. 

A little over two years ago, in  J.I.D.: NIAID's Strategic Plan To Develop A Universal Flu Vaccine, we looked at the National Institute of Allergy and Infectious Diseases' short term goals.  

Credit NIAID

Admittedly, not quite what most people think of when you say `universal flu vaccine', but still a considerable improvement over what we have right now.   

All of which brings us to a lengthy (144 page) technical report, published yesterday by the ECDC, on the effectiveness and safety of our newer generation of flu shots; including MF59 ® adjuvanted, hi-dose, cell-based, and recombinant HA vaccines. 

The full report will be primarily of interest to vaccinologists, but others may wish to have a look as well. The tepid findings - based on limited evidence - in the executive summary (below) are a reminder of the importance of creating a truly game-changing flu shot. 

Systematic review of the efficacy, effectiveness and safety of newer and enhanced seasonal influenza vaccines

Technical report
1 Oct 2020 

Overall the evidence base for the efficacy and effectiveness of newer and enhanced influenza vaccines appears limited at present, with a number of potentially relevant studies identified as ongoing.

It is likely that the use of such vaccines provides greater protection than no vaccination at all, when the usual considerations of circulating strain matching are applied. Evidence regarding the comparability of these vaccines to traditional seasonal influenza vaccines is uncertain with a lack of available literature.

The safety profiles of these vaccines are largely in keeping with that expected when considering their individual compositions and, for the most part, they appear to be well tolerated.

Some suggestions are provided to enhance research conduct and reporting regarding these newer and enhanced influenza vaccines which are anticipated to improve the data coverage overall and facilitate future decision-making regarding the use of such vaccines.

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Systematic review of the efficacy, effectiveness and safety of newer and enhanced seasonal influenza vaccines for the prevention of laboratory-confirmed influenza in individuals aged 18 years and over - EN - [PDF-10.35 MB]