Seasonal influenza vaccination for professional athletes – who’s for the jab?

It’s that time of year for many of us in the Northern hemisphere when colleagues involved in caring for participants in elite sports are being asked, ‘Doc, should I have a flu shot?’

The decision may have already been made by the athlete (or, indeed, the Club or organisation) that they either ‘need’ or ‘don’t need’ influenza vaccination, which may make life easy or hard for clinicians if there is a difference of opinion on the subject.

Whilst our patients might perhaps expect an easy and straightforward ‘yes’ or ‘no’ answer on the question of seasonal influenza vaccination, the reality is that the decision to be made on requirements for seasonal influenza vaccination requires a consideration of a number of complex factors relating to the susceptibility of individuals and populations to the disease, together with the risks of serious complications to particular groups of individuals and their contacts in society.

These can be broadly grouped into extrinsic and intrinsic factors :

1) Extrinsic factors

– Regional projected population prevalence of viral load (based on WHO Health surveillance data)

– Regional variance in delivery policies and availability of vaccines (may include rationing)

– Meteorological forecasts

– Other socioeconomic factors (occupation, housing etc)

2) Intrinsic factors

– Co-morbidities such as asthma, diabetes

– Patient choice

In the United States, seasonal influenza vaccination is recommended for all individuals over the age of 6 months, but local recommendations vary considerably in different countries. In the UK, for example, universal vaccination is not currently recommended, with a more targeted approach being adopted towards vaccinating certain individuals.

When it comes to particular groups such as athletes, all of the considerations mentioned above apply but there is the added question about the effect of moderate-to-high levels of physical activity on immune system function and susceptibility to infection to consider. It may also be important to consider the effect of travel and time-zone adjustment. In addition, when it comes to hard outcomes, it’s important to consider the evidence for the effectiveness of influenza vaccination on disease prevention in individuals, and for prevention of cross-infection of colleagues within a team environment.

There is a whole host of guidance available to clinicians from organisations such as the World Health Organisation, the Centers for Disease Control and Prevention, and the Department for Health in the UK which describe recommendations for vaccination in individual groups related to age and co-morbidities.

However, there is little information in the literature based on good quality evidence to inform clinical practice when it comes to the immunisation of professional athletes based on a consideration of the effect of high levels of physical activity on immune system functioning.

Perhaps as our understanding of exercise immunology improves, the basic science knowledge will better inform clinical practice.

An interesting position statement on immune function and exercise and maintaining immune health, published this year over two articles in Exercise Immunology Review should help us to get there. The articles provide a comprehensive review of topics in exercise immunology, and are available on the web here (Part 1) and (Part 2).

In the meantime, for those of us in the UK and other Countries where universal seasonal influenza vaccination is not currently recommended, the references at the end of this post may prove useful for those of us making decisions with our athletic patients.

CJSM would be interested to hear your thoughts and strategies for seasonal influenza vaccination of athletes, especially from team physicians.

1)  Constantini N et al. 2008. Vaccinations in sports and recommendations for immunization against flu, hepatitis A and hepatitis B.  Harefuah 140(12):1191-5

2) Daly P, & Gustafson R. 2011. Public Health recommendations for athletes attending sporting events. Clin J Sports
Med. 21(1): 67-70

3) Schaffner W. Rehm SJ. File TM Jr. 2010. Keeping our adult patients healthy and active:the role of vaccines across the lifespan. Physician and SportsMed 38(4): 35-47

4) Malm C. 2004. Exercise Immunology : the current state of man and mouse. Sports Medicine 34(9): 555-560

5) Ross DS et al. 2001. Study indicates influenza vaccine beneficial for college athletes. West Virginia Medical Journal 97(5): 235

6) Tarrant M & Challis EB. 1988. Influenza vaccination for athletes? Canadian Medical Association Journal 139(4): 282

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About Chris Hughes
Associate Editor, Clinical Journal of Sport Medicine

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