Will this Year’s Flu Vaccine Perform as Expected?
With the imminent arrival of the influenza season in the northern hemisphere, essential flu vaccination uptake begins as well as proactive surveillance programmes for influenza like illnesses (IFL).
During 2014/2015 the flu vaccine performed better than initially thought at fighting the virus and saving lives and appears to have helped much more than previously estimated. Despite this the overall death rate over the flu season was particularly high in the elderly population.
It would be expected in a normal flu season that the vaccine would be at least 50% effective. Early this year, the first estimates were that the vaccine was reducing flu by just 3.4% - which was concerning.
This estimate was driven by what seemed to be an exceptional difficulty with the H3N2 strain of the virus, a strain which tends to have serious effect on the elderly. It was looking as though the vaccine had no discernible effect against that subtype. As the flu season progressed the effects of the vaccine were seen to improve with the final effectiveness rate estimated at 34% - The flu vaccine remains the best protection against the virus and still proved a life saver, despite its low efficacy.
It is the importance of getting vaccinated which counts, even when efficacy is not 100% - if you end up contracting flu, the vaccine will help protect you by regulating your immune system, preventing you from contracting a more severe case of flu, or even worse death. It will also protect those around you - if flu doesn’t kill you it may kill someone you pass it on to.
How do we know which strain of flu will be most prevalent each year? The flu virus is constantly mutating which means that each year the World Health Organisation (WHO) monitors the epidemiology of flu viruses worldwide to predict which potential strains should be included in the flu vaccines for the coming winter flu season.
For the 2015/2016 influenza season in the northern hemisphere winter, it is recommended that trivalent vaccines are used & the WHO has announced that they will include the following strains:
- An A/California/7/2009 (H1N1)pdm09 like virus
- An A/Switzerland/9715293/3013 (H3N2) like virus
- A B/Phuket/3073/2013 like virus
In the hope that this year’s vaccine will be more effective, A/Switzerland/9715293/3013 (H3N2) has been included as it is a closer match to the drifted H3N2 strain seen circulating in the northern hemisphere during the 2014/2015 flu season. Antigenic drift can occur over the duration of a flu season, causing changes/mutations in the virus, which means they no longer match up precisely with the manufactured flu vaccine.
Determining the closest match between circulating viruses and those found in the vaccine gives the most effective flu vaccine. However, this is limited by the length of time available between the WHO recommendations of which formulation & strains to include in the vaccine (usually February) and the time available for the complex manufacture of producing the vaccine.
This delay in time can create a problem whereby the strains in circulation might not be the right ones by the time flu season starts in the autumn and flu vaccination programmes begin. Also, as mentioned previously viruses go through "antigenic drift" – so even if the correct strain of virus is included in the vaccine, the strains can mutate as they reproduce making the vaccine ineffective.
Whilst it is impossible to predict what the 2015/2016 flu season will bring about, due to the timing, severity, vaccine efficacy and the length of the season, one thing is predictable:
Medical Wire is prepared and does so by increasing levels of stock in preparation for a rise in demand for Viral Transport devices.
Medical Wire has it covered with a full range of Virology products for all your needs. www.mwe.co.uk/microbiology-lab-supplies/viral-transport-medium/
Don’t get caught out this winter – plan ahead with stock levels and be prepared for all surveillance programmes and testing for the flu virus.
For further details on Sigma-Virocult® and Sigma-VCM™ contact your local account manager who will be happy to advise you on the full range of products available.
For full details visit www.mwe.co.uk
Date Published: 20th October 2015
Source article link: MWE