Immunization and disease in expatriates

P::hL Hhh, Lore1. (1979) 93. 269-273

Immunization and Disease in Expatriates* D. M. Mackay M.B., Ch.B., M.F.C.~V}.

Deputy Director. Ross InsEtute o f Tropical/-/yg/ene, London Introduction Two o f the most interesting and significant sociological developments o f our time have been the great ir~crease in the mobility of people and the increasing rale at which they travel. More and more people are travelling t~trther and further and faster and faster, and there is no sign o f these trends doing anything other than escalating. Fifty years ago, a train journey from Glasgow to Edinburgh, or to London, was an adventure. T o d a y a plane flighl to Calcutta or Hong Kong is commonplace. This has one very important consequence, which is that more and more people are coming into contact with the exotic diseases, those diseases wkich we have in the past been accustomed to regard as the "'tropical" diseases. Not only so, but the increasing speed o f travel n~eans infinitdy increased opportunities for the importation o f these diseases. In the past, a man contracted cholera in-Calcutta the day before he boarded his ship, he developed the clinical disease at sea, died and was put over the side. He was not a public health problem. Now he contracts cholera the day before he boards his plane and by the time the disease shows itself he is in London, or Dublin, or the Yorkshire dales, and he is very much a headache to the public health authorities. Tru~-'ellers may be o f two rather different categories, i.e. those who are paying a short visit overseas and those who are to reside in an overseas territory for some period o f time. Obviously their respective needs in the way o f advice m a y be somewhat different. Perhaps it is wise always at the start o f such advice to m a k e it clear that ,there is no such thing as a schedule o f advice which will guarantee health. Time and time again people who seek advice seem to be seeking a gold plated guarantee that they will not fall ill. There is no such guarantee. Those who travel overseas and come into contact with exotic diseases take a calculated risk, which they have to accept. That risk can be greatly minimized by the good advice and the conscientious observance of it. ~!t can only be minimized, not abolished. Those who require guara.ntees should be advised to stay at home. In this respect, wha~ applies to the adult male applies with even greater force to children and to the pregnant woman,

The advice which the physician can ~ive to a~yone contemplating overseas travel thlts conveniently into three sub-divisions. (1) What he should do in preparation for travel. (2) What he should d o w h i l e he is overseas. (3) What he should do after his return. If a schedule o f advice is developed systematically along these lines, important facts are not likely to be missed° *A paper read a! a meeting o f ihe London G r o u p of the Society o f Occupational Medicine o n 9th November 1977, 0038-3506/79/050269 + 05 $01.00/0

'g) 1979 "["he Society o f Community Medicine

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Preparation for Tray,l,! Tile most important thing under this heading is the w,~',~;}kingout and implementi~ag o f the be~t po.~sible inoculation schedule. A standard sched~/t~e would be as follows: smallpox yellow fever typhoid cholera tetanus poliomyelitis hepatitis Smallpox vaccination, previously mandatory aJmost cr,,eryxvhere, has now undergone great changes since the successful smallpox eradication p,.~ogramme in many parts of the world. Many countries have now altered their requirements ?but others have not yet done so. W.H.O. publicalions should be consulted. It is probably wis,~:to continue to regard vaccination as mandatory for the East African region, i.e. Ken'~',:,t, Somalia, Ethiopia, Sudan. Probably in two or three years vaccination requirements wi|~ have been totally withdrawn. Tlle risk of contracting smallpox is now so infinitesimal that a very liberal policy in the issue of exemption cerliiicates, especially to children, is justified. The only problem with this is, of course, that there is nevcr any guarantee that they wile be accepted. In most cases they are. For international travel purposes, smallpox vaccination should be renewed every three years. Yellow fever is required for those whose travel includes most of Africa and Central and South America. It is a highly effective vaccine which hardly ever gives rise to any adverse reaction and which lasts for ten years for international travel purposes. The ooly weltknown comra-indication is a sensitivity to eggs, which occasionally occurs. Typhoid vaccine, though not 100'~.~ieffective, is a useful measure and should always be taken. Typhoid is a wide spread disease, not ot all uncommon in continental Europ:, especially the Mcdilerranean region. The combined typhoid-paratyphoid vaccine (TAB) has been used for many years but now there is a general feeling that monovalent typhoid vaccine gives better results with fewer side-effects. There seems no good evidence that the paratyphoid elemenls in TAB are in fact useful. Probably typhoid inoculation should be reinforced every two years, except where lhe subject is living in an area where typl,oid is known to be endemic. Then a yearly booster is probably wise. Cholera vaccine is an unfortunate one. in that it is of limited effectiveness (commonly believed to be about 60~to) and it lasts for only a short period (probably not more than 4-5 months). W.H.O. no longer recommend thzt cholera inoculation he required for purposes of international travel but some countries still require it and others are quite likely to impose a sudden requirement in the presence of an outbreak. It is advisable for the traveller to Africa and Asia to have the inoculation, even if only for the simple reason that 60°~,~ protection is be~ter than no protection. The present pandemic of cholera has not invaded the New World, so probably the traveller to South America need not include it in his list. Residents in areas where cholera is endemic should :have booster doses every 4-5 months. Tetanus toxoid is a very important prophylactic inoculation. No person should go o v e r seas without complete protection. It is a very effective vaccine and requires boosting only once in 5 years or so. The reasons why it should be regarded as mandatory are twofold. Tetanus is a widespread disease of very unpleasant nature and a considerable mortality, so protection against it is obviously desirable. Secondly, wherever one goes overseas, the

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slightest i~'~juryor accident is usually regarded as an occasion to give a so-called prophylactic dose of antitetanus serum (ATS). This is one of the most objectionable medicanaents known to man. It is a horse serum and there is a high risk of adverse reactions, including even falal, cases ofanaphylaxis. It is to be avoided at all costs. Those who have had a complete course of tetauus toxoid never require ATS, only at most a booster dose o f toxoid. This 'should be carefully explained to all concerned, so that they can resist attempts to give lhem ATS. Poliomyelitis is a major risk o f the expatriate in the tropics. Fewmedical officers who have served for a long time in tropical areas have not seen several cases in expatriates and all 1oo often death. This inoculation, by the use oforal Sabin vaccine, is sosimplethat no one should go without it. There is no strong consensus o f opinion about reinforcemem. Probably once in five years is reasonable. Virus hepatitis is a major hazard and is widespread in the tropics and sub-tropics. The use o f human immune globulin is to be recommended. It is not certain how long its effectiveness lasts but probably renew~al every 6 months is indicated. It is o f course an agent o f passive. not active immunity. Those who live overseas for long periods probably will not continue to have it but the short term visitor or resident should certainly take advantage of ils existence. Certain other vaccines exist but are not used routinely. They may be required for those who are exposed to special risk either from the nature of their employment or the place to which they are going. These ~clude plague, typhus and rabies inoculation. If the question o f their use arises, probably e~pert advice should be sought. Special considerations arise ,in the case of pregnant women and young children. It is probably unwise for pregnant yeomen to go overseas at all, unless they are very sure o f the quality of obstetric care (including blood transfusion services) which they can have in case of need. It is unwise to give pregnant women any inoculations at all and, if they insist on going, they should be advised to ~have their inoculation schedule as soon after delivery as possible. Tetanus toxoid may be an exception to this rule, as it is frequently used in pregnant women overseas without any known harmful effects. Infams should have their normal immunization schedule, including smallpox where indicated, DPT, poliomyelitis and BCG vaccines. Yellow fever can be given ~t~ochildren over the age of I year. Typhoid and cholera are usually reserved until after 2 years. There seems no obvious contra-indication to immune globulin for hepatitis. It is important that the intending ~traveller should have a medical check prior to his departure. Certain people tto not do well in the tropics. Heart disease and hypertension are probably eontra-indications. So are those who have had spleneetorny; they react gravely to malaria. Allergies, including asthma, and chronic skin diseases are contra-indications. In cases of doubt, expert advice can be obtained. Dental checks are also important. In many places overseas such dental care as is available is rudimentary and often unhygienic. It is much better to go overseas with sound .demal health than to fall into the hands o f the local "dentist" abroad. It is o f the utmost importance to warn the intending traveller or overseas resident of the malaria risk. Advice can readily be obtained on this. Wherever a malaria risk exists. advice must be given on the right prophylactic to be taken and this regime should be started prior to arrival. Also the traveller should have with him enough for the first few weeks or months, until he establishes his local means o f supply. It is absolutely vitalthat he should be scrupulous i~a his anti-malarial precautions, and that no break should occur in his prophylactic regime. For most places, proguanil in an adult daily dose of 100 mgs is adequate. F o r equatorial Africa, i.e. all Africa from the southern border of the Sudan to the northern

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border of the Republic of South Africa, the dosage should be increased to 200 rags. There are places where proguanil resistance occurs. These are Fatchy and no master-map seems to exist. Those who go to malarious areas should be advised to start with proguanil, and on arrival lake the best local advice available. It is probably unwise to change unless very reliable advice to the contrary is obtained. When it seems necessary to change, in Africa chloroquine may be used in an adult weekly dose of 300 rags chloroquine base. Long term residents may have to beware of the risk o f eye changes after very long-term use. In much of Asia, chloroquine rests'lance occurs and the aitcrnative to proguanil is a pyrimethaminesulphonamide combination, e.g. Maioprim or Fansidar. If time permits, it is highly desirable tha't people going overseas, especially to fairly remote areas, should have taken a standard course in first aid. This is a much neglected subject. Those who make frequent trips overseas should hold, and keep renewed, a recognized first aid certiticate. Frequently the physician is faced with a time problem in his recommended inoculation schedule. Suddcn decisions are laken and people present for advice wi~h n o possibility at a'll o f carrying out a proper schedule. Then the physician has to assess the risk priorities for the country to 'which the subject is going, the nature o f his work there, etc. and select what can be give~7, in the time available which will be of most benefit. He is helped in this by the fact that old rules about intervals between various injections are n o w being more and more disregarded, with no obvious disadvantages. For employees who are likely to be required to go overseas from time to time, it ,may well be wise to keep an inoculation register and by using Ihis to keep all inoculations permanently in date. Activities while Overseas

It is not possible to write at length here o f the regime o f living which is appropriate in overseas co~dition.~. Largely this is to be determined by the conditions of the actual area involved. However, certain broad lines can be laid dox~n. It is time well spent for the occupational physician to go over the points that are most important with the intending traveller. The continuance o f malaria prophylax,is without a break is probably the most important single measure, plus sensible precautions against mosquito bite, e.g. long trousers and long sleeves at sundown, mosquito nets etc. The commonest condition which will plague the traveller will be diarrhoea and it is essential for him to realize that gastro-intcstinal infection goes in via the mouth. There are a few ,golden rules: Ca') Never eat uncooked food, however tempting. (b) Never drink raw water, unless its safety is vouched for by a very reliable opinion. Everyone will break these golden rules--and pay the penalty! Other points to note are that ice is only as ~ f e as the water from which it is made, and that beer and international brands of "'soft" drinks are normally safe. Those going to Africa or Central/South America must be instructed about the dangers of Bilharzia and the need to avoid bathing in infected waters. Those taking up residence for a period overseas will usually employ urge or more domestic servants. The dangers of infected domestics should be stressed and the necessity to have them checked, both before employment and periodically during employment. Expatriates who become ill should seek medical advice early. There is a tendency not to d o this and it can lead to very difficult situations. British embassies and consulates usually keep lists o f local doct~ors who are used by them and from those a doctor can be selected.

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Occupational physicians should be very ready to recommend repatriation when they have reports of sick expatriate employees. It is usually most economical in the end to repatriate quickly. When in doubt, repatriate. it is a good thing to supply each traveller with a copy of the Ross lnstitute's booklet ~'The Preservation of Personal Health in Warm Climates". This discusses living in the tropics and sub-~ropics in some detail and is a very useful vade mecum. Often advice is asked as to medical supplies to be taken. The less that is taken the 'better, within reason. Antimalarials. aspirin and first aid supplies are probably all that is necessary unless the area to be visited is remote. Supplies can be bought in most places, and it is pointless to load up with drugs against conditions which the traveller cannot diagnose anyway. If remote areas are to be visited, tetracycline and some antidiarrhoeal preparations are useful, and probably some chloroquine to deal with a malaria break 'through. Some short-trip travellers may wish Io utilize streptotriad as a prophylactic against diarrhoeal infection. If the visit is short, i.e. not more thah say 10 days, this is a useful measure.

After Return Antimalarials should be continued for 6 weeks after leaving the malarious area. This requires considerable self-discipline but must be stressed. The question of a "check-up" after return from overseas is often raised. Probably general check-ups are unrewarding and uneconomical for the amoun~ of disease they reveal in a largely asymptomatic group of people is extremely small. What is much better is to warn each returned traveller to be vigilant for any ~abnorm~.l sign or symptom and to report it immediately, either to the occupational physician or to his general .practitioner. When he does so, he must state loud and clear where he has been, and when. The important question in the medical history of such people is"Unde venis?'" and they must make sure that the doctor, whoever he is, is fully aware of their movements, it is pat~ticularly important to remember malaria and to think of it whenever fever is prominent and continued. Where there is suspicion of tropical disease, expert opinion should be sought early.

Aids for the Occupational Pfiysician Good reference works on tropical medicine are always very useful, and copies of "Woodruff" & "Manson" should be available always on the bookshelf. The Ross Institute of Tropical Hygiene, Gower Street/Keppel Street, London WCI E 7HT (telephone 01-636 8636) is available during all normal working hours to give advice on any question regarding preventive medicine overseas. This includes suci~ points as the distribution of malaria, appropriate prophylaxis etc. The Ross Institute is also prepared to put on seminars for occupational physicians on this subject and to give short courses to personnel going overseas, provided a sufficient number can be brought together at one tinae. Help and advice on clinical aspects of tropical and exotic diseases can always be obtained from the Hospital for Tropical Diseases, 4 St. Pancras Way', London NWI 0PE (telephone 01-387 4411),