By Tonia Buzzolini*
Who should get vaccinated against rabies before heading overseas?
Until recently, the conventional thinking among travel medicine professionals was that the length of the trip and the destination should be the main deciding factors.
That is, pre-travel rabies vaccination was for people travelling to, or living in, a country with a high incidence of rabies for more than one month – particularly if they were at higher risk of animal bites because they‘re backpacking in rural areas, travelling by motorbike or bicycle, working with animals etc.
For stays of less than a month, a warning to avoid contact with animals and to seek medical treatment urgently if bitten was thought to be enough.
There were a number of reasons for this pragmatic attitude.
Firstly, rabies deaths remain rare among travellers. This may be because rabies infection is usually slow to appear and most westerners do eventually get treatment AFTER they get bitten, preventing infection. Yet an estimated 55,000 people die from rabies each year, according to the World Health Organisation, with most of its victims failing to access timely post-exposure treatment (or unable to afford it.)
Secondly, the cost of the vaccine – around $300 for the 3 doses – is prohibitive. Travellers on a budget were reluctant to get it when they were already up for other travel immunisations to protect them against diseases considered a higher risk.
Thirdly, rabies vaccine is administered over at least 3 weeks (the standard 0, 7, and 28 days can be accelerated to 0, 7, and 21 days). All too frequently, travellers don’t leave themselves the ideal 4-6 weeks to begin vaccinations prior to travel.
All of which often puts the subject of rabies vaccination firmly in the dog house during pre-travel medical consultations.
Destination the critical factor
But, our view of pre-travel rabies vaccination has changed.
Recent scientific studies on travellers bitten by animals confirm that the length of stay is less critical than the destination itself when it comes to deciding who should consider pre-travel vaccination. The studies consistently show:
– More short-stay travellers (those overseas for less than a month) are being bitten, mainly by dogs, but also monkeys and cats.
– Most rabies exposures occur in Asia, particularly India, Indonesia, China, Nepal, or Vietnam (among the most popular destinations with travellers the world over).
– Effective post-exposure treatment is often very difficult to obtain in many countries and, when available, it’s expensive.
Booster shot no longer needed
Another factor that has altered our thinking regarding pre-travel vaccination is an important change to the rabies vaccination guidelines: a booster dose is no longer recommended once the initial course of vaccine is completed. (The exception is people who are at consistent risk of rabies.)
Previously, the guidelines in the Australian Immunisation Handbook stipulated that all travellers should have at least one rabies booster.
When you consider those factors, I believe it makes sense to think of rabies vaccination as a travel health ‘insurance policy’: a kind of safety net that you could come to rely on sooner or later – especially if you regularly visit higher-risk countries in Asia, Africa or Latin America.
I recently attended the recent 10th Asia Pacific Travel Health Conference in Vietnam and that new view of rabies vaccination was the prevailing one among the infectious disease experts who gave presentations and ran workshops for almost 500 travel doctors and nurses from 38 countries.
We discussed a number of studies on rabies involving travellers who received animal bites and required follow-up treatment for possible exposure to the virus either during their travels or after they returned home.
Compelling evidence
The largest and most compelling study1 involved a survey of 23,509 travellers seen in travel clinics around the world between January 1998 and May 2005. The clinics were members of the GeoSentinel Surveillance Network, which was established by the International Society of Travel Medicine (ISTM) to monitor and collect data on travel-related illness.
Several studies found:
– The majority of patients were leisure travellers aged 20–50 years (63%).
– 12% had travelled for less than 7 days, 53% for less than 28 days, and 85% for less than 3 months.
– Most of those treated (67%) were potentially exposed to rabies in Asia – mainly in India, Thailand, Indonesia, China, Nepal, or Vietnam.
– Dogs were the most common culprits (51%), followed by monkeys (21%), and cats (8%).
Rabies infection always fatal
What makes rabies such an important issue for travellers visiting a rabies-infected country (which includes much of the developing and developed world) is the fact that once symptoms appear the disease is invariably fatal. There are no second chances.
Typically, the period between contracting rabies and symptoms appearing is 1-3 months, however symptoms can begin in less than a week or not emerge for more than a year. It all depends on how long it takes for the virus in the infected animal’s saliva to reach the victim’s central nervous system following a bite or scratch.
Because it is always fatal, even those people who have been vaccinated prior to travel should receive post-exposure treatment after a possible exposure.
Once a traveller is bitten, time becomes critical – especially for those without the protection of pre-travel vaccination. The WHO estimates that more than 15 million people worldwide receive post-exposure vaccination each year, preventing hundreds of thousands of rabies deaths.
To be completely effective, post-exposure treatment for rabies (called Post-Exposure Prophylaxis or ‘PEP’) should involve a blood product called Human Rabies Immune Globulin (HRIG), which is injected at the site of the wound before or with the first vaccination. Designed to initiate an immediate immune response, it is the HRIG more so than the vaccine that is usually hard to get overseas (and, therefore, always expensive).
For unvaccinated travellers, PEP also involves a month-long course of 4-5 rabies vaccinations, while just 2 are recommended for those vaccinated prior to travel. Nor do vaccinated travellers require HRIG – an important benefit of pre-travel vaccination.
Rabies awareness lacking
Because Australia does not have rabies, Aussies are generally not aware of the risk this deadly disease presents and remarkably naive when it comes to contact with animals they encounter while travelling. On average, around a dozen Aussies return home from overseas each month needing post-exposure treatment.
You may recall a Travelvax Report last year highlighted a Queensland study of 136 Australian travellers bitten by animals overseas between 2008 and 2012.
The study showed that 38% of the travellers were bitten when they tried to pat or feed an animal, while 28% of the attacks were totally unprovoked (which can be an indicator that an animal is rabid).
Only 31% of those exposed received appropriate first aid at the time of the injury and the average time between exposure and starting treatment was 17 days. For many of those who did begin treatment while overseas, the recommended protocols were not followed.
Most Aussies only become aware of rabies after they’ve been bitten – usually by a local person or by a more experienced fellow traveller warning them. The challenge then becomes immediately treating the wound correctly and then quickly finding a medical facility that has the medication to provide effective treatment.
In many countries – especially in remote areas – that’s simply not possible and for many unvaccinated travellers the best option is to cut short their trip and access the (free) treatment back home. (Travel health insurance is especially important if you’re not vaccinated: if bitten you can get medical care at no cost.)
But, pre-travel rabies vaccination makes post-exposure treatment less urgent and takes much of the anxiety out of waiting for the all-clear.
For more information on rabies and other vaccinations recommended or required for your next overseas trip, please call Travelvax Australia’s travel health advisory service on 1300 360 164.
* Tonia Buzzolini is the National Operations Manager of Travelvax Australia. A registered nurse, she holds post-graduate qualifications in Public Health & Tropical Medicine. She is also a member of the International Society of Travel Medicine and holds the Certificate in Travel Health®.
REFERENCES:
(1) Gautret P, Schwartz E, Shaw M et al. Animal-associated injuries and related diseases among returned travellers: a review of the GeoSentinel Surveillance Network. GeoSentinel Surveillance Network. Vaccine 25(14), 2656–2663(2007).