Vaccination: Is Defense The Best Attack

Without doubt, vaccination is one of the greatest triumphs of modern medicine. Many serious diseases that used to routinely maim or kill large numbers of people are no longer a threat. More than that, vaccination can prevent outbreaks of less serious illness, which although not life threatening, are still unpleasant, leading to missed time from work and school.

Anyone with young children or who has travelled extensively abroad will (hopefully) understand that a programme of vaccination is either required or recommended. When it comes to the travelling athlete however, the situation is rather more complex. While the basic vaccinations (eg typhoid, hepatitis etc when travelling to certain regions of the tropics) are of course still required, clinicians will also want to ensure that their athletes stay as well as possible to compete at their full potential. A mild illness that is an inconvenience to a tourist may be a disaster for an athlete focusing on the peak of his/her season!

Sports clinicians may therefore wish to consider extra vaccinations to minimise the risk of more minor conditions. However, this approach raises a whole new set of issues. For example, which additional vaccinations may be use for athletes who regularly travel abroad? What are the possible side effects of these extra vaccinations and how should vaccines be timed to maximise immunity during the competition, while minimising disruption to training in the run up to competition?

Athletes Are Different

There exists some uncertainty about the most appropriate vaccination regimens in athletes among team doctors and other physicians because general public health vaccination guidelines cannot be easily transferred to elite athletes. Complicating factors include the typical circumstances of athletes� daily life, such as frequent travelling to foreign countries or close contact with teammates and opponents, which might indicate the need for a modification of recommended vaccination schedules. In addition, intense physical activity of training and competition with its possible effects on the immune function can affect decisions about execution and timing of vaccination.

Other complicating factors are that vaccination recommendations are formulated around a public health policy rather than for specific individuals and are likely to change over time(1-3). Also, there�s the issue of cost effectiveness; the majority of vaccines that are not generally recommended are not recommended because the medical benefit is not regarded sufficiently balanced with the costs if implemented across the whole population. This is despite the fact that they may be potentially beneficial in specific individuals(4,5). It�s also important to understand that generalised recommendations take no account of the implications of the effects of illness in athletes, which can be far more profound and far reaching than in the general public (see Box 1).

Further reasons as to why athletes are different when it comes to vaccination include the following:

• Athletes are often in close contact with opponents and teammates, which increases the risk of transmission of many diseases, particularly respiratory- transmitted diseases(9,10). Typically, a contact of less than 1-2 metres distance is necessary to transmit diseases such as influenza or other respiratory- transmissible agents such as varicella(11,12).

• For blood-borne diseases, the transmission risk due to sport is less pronounced but athletes are still at higher risk than the general population(13,14).
• Even healthy non-vaccinated athletes being exposed to an infectious agent (eg contact with a diseased individual) may have to be excluded from training and competition for medical reasons. Usually, such an exclusion has to last for the complete incubation period of a disease, which may be up to three weeks.

Putting all these factors together, the recommendation is that elite, competitive athletes should be vaccinated more aggressively than the general public(15).

Which Vaccinations?

The decision as to which vaccinations are given prior to foreign travel will depend on a number of factors, including the travel�destination(s), the nature of the sport and the health/vaccination history of the individual involved. Regardless of these factors however, it is recommended that ALL adult athletes are routinely vaccinated against the following: