JABS AND JOURNEYS
by Michael Nightingale
Epoch Magazine 1982
One of the most fascinating studies in medicine is that of the epidemiology of infectious or zymotic diseases, and in recent years such diseases are being seen increasingly in their ecological perspective. The cyclic nature of epidemics has long been an observable fact but the explanation for it has only begun to be better understood with the realisation that stable equilibria between species is scarcely attainable in nature; so that there is always conflict between host and micro-organism, circumstances sometimes favouring the one and sometimes the other. In spite of this conflict there is also another side to the coin. It is never in the interests of a predator to decimate its prey or of a parasite to kill its host; to do so would mean starvation. If micro-organisms were to cause the death of a host, this would usually spell their own untimely end, though some bacilli, such as those associated with plague or anthrax, are exceptions to this rule. For this reason it is thought that a highly virulent pathogenic organism, such as a measles virus, represents a more primitive and less well adapted species than that of poliovirus, for example, which normally only causes disease in somewhere between 1 in 50 and 1 in 5,000 of those people they infect (1,2).
Other organisms have become so well adapted that they do not cause disease at all unless for some reason they are introduced to an area of the body where they are not normally to be found. Escherichia coli, for example, are habitual residents of the gut, where they normally do no harm. In other parts of the body they may cause meningitis, septicaemia or other pathological conditions. Streptococci in the throat are usually harmless but may cause a serious or fatal infection in the uterus. Still other organisms, described as symbiotes by biologists, are actually beneficial to their host. Many of the organisms in our own intestinal tracts assist in the breakdown and digestion of foods, some are capable of manufacturing vitamins and other essential elements of nutrition, and nitrogen-fixing bacteria have been found in the digestive tract of some animals (even a few humans) which in certain cases may enable the host to survive on very small amounts of protein. Bacteria on the skin protect it from colonisation by pathogens. However, any of these organisms can become harmful if conditions are wrong.
So far we have looked at adaptation, albeit very briefly, from the viewpoint of the microbe. The host, too, can adapt, and it is well known that the mounting of the specific immune response is one way in which the higher animals at least may protect themselves: Normally, the saliva, lacrymal secretions, gastric juice, urine and other body secretions all help to restrict unwanted entry by foreign organisms through any of the bodys portals; whilst lyzozymes, interferon, phagocytic cells and non-specific antibodies (opsonins?) work to eliminate them once they have gained admittance. The mouth and alimentary canal are, strictly speaking, outside the body, and well behaved mirco-organisms may be allowed to stay in these areas within reasonable numerical limits. Organisms which penetrate mucous membranes and gain admittance to the inner tissues or to the blood do so because the health of the membranes is impaired or because the organisms concerned are particularly virulent or present in extremely large numbers, or both. Overcrowding, which can easily produce high concentrations of microrganisms, is therefore an important cause of this sort of infection(3). Poor nutrition (4,8) and faulty eliminating, which give rise to unhealthy tissues or toxic laden blood, wilt undoubtedly facilitate the entry or organisms and their subsequent pathogenicity, although the far-reaching effects of nutrition on infection and disease will be described later.
Overnutrition, too, can assist the same process, as this often gives rise to excessive mucus secretion, which in turn provides a tasty dish for many a microbe. Such microbes may then become so numerous that they are unable to metabolise properly and eliminate toxins. They may invade local lymphoid tissue or they may find their way further into the respiratory tract. Whatever they do it is certain that they have to be stopped by some process more powerful than that of the general defence mechanism which has anyway become weakened. it is at this stage of infection by unwanted organisms that the specific immune response comes into play, and in many cases there needs to be a local response. In the presence of local antibody, phagocytic cells become much more effective at devouring a particular microbe, as if the antibody were a piquant sauce making the meal more attractive and digestible, whilst phagocytes themselves become immunologically competent, i.e. more adept at recognising and consuming the microbe or infected cells even in the absence of humoral antibody. At the same time antibody is able to combine with viruses and cover up vital structures, thus preventing their attachment to the cells of the body and their subsequent replication.
One of the reasons why influenza vaccines have given poor immunity in the past is because, being administered systemically (i.e. into the blood), local immunity in the respiratory passages (the portal of entry for this virus) has often been negligible (9-14). This combined with lack: of knowledge concerning the antigenic components may exacerbate the problem. A good example is where haemagglutinin antibody was once used to measure immunity to influenza; whereas it is now known that anti-neuranimidase antibody is of equal or greater importance (15). A similar fact (i.e., poor local immunity) probably accounts for the failures of whooping cough vaccines (16-17), Salk polio vaccines (18), cholera vaccine (19-20), and possibly bacterial vaccines generally 921-25): though some authorities think that this is because of other problems such as variations in antigenicity (26-30). In virus infections where viraemia is typical, vaccines given parenterally may be expected to be more successful.
Of all the diseases mentioned the virus connected with influenza is known to vary the most frequently. The most recent findings concerning influenza vaccine are noted in an article in the Health and Social Service Journal by Dr. Harvey Gordon (31) the Deputy M.O.H. for the London Borough of Wandsworth. He claims that the Borough Council offered this vaccine to all its employees at a cost of £500 and that it lost 722 working days as a direct result. He concluded that no useful benefit could be proved statistically regarding this vaccine.
Whilst influenza vaccine is not one that is used routinely, nor one that is urged under international regulations, it is probably not much less effective than typhoid, cholera or whooping-cough vaccines. It is difficult to make comparicons with smallpox vaccine since the results of this are somewhat conflicting (32), but generally speaking it does not seem to provide much protection during epidemics. On the other hand it does appear to be quite helpful in the absence of an epidemic!
One of the problems which has not been squarely faced is that of the whole question of disease causation. Dr. Stewart (33), Professor of Epidemiology and Pathology at the University of North Carolina School of Public Health and Medicine, described the germ theory of disease causation as a gross over-simplification, and many authorities have challenged the theory before and after him. Dr. Fraser (34) and his colleagues swallowed vast numbers of virulent Eberth bacilli, Kiebs-Loffler (diphtheria) bacilli (now better known as: Salmonella typhosa and Corynebacteria respectively) and pneumococci without any ill-effects. He also describes a case of each of these three conditions in which the organisms were not to be found at the onset of the disease but only appeared in the later stages.
Dr. Fraser placed his finger on the crux of the problem, for if the organisms appear as the disease develops, then it would seem that it is the disease that causes the organism rather than the other way round. This is certainly likely to be the truth of the matter in the case of bacteria, since these organisms feed on dying or decaying cells. It is not at all unlikely that in the presence of dead organic material these micro-organisms multiply rapidly and start to produce toxins because they become overcrowded and their metabolicwastes are not being removed quickly enough. On the other hand it is now thought that the diphtheria bacterium only produces the poison which causes diphtheria when it has itself been infected by a virus (35).
The concept of the disease producing the "germ" is certainly not a new one for it was originated as a scientific principle by Professor Béchamp, a contemporary of Pasteur whose work was plagiarised and distorted by the latter. Bèchamp, in fact, can lay claim to more original thinking, better scientific training and greater honesty than Pasteur (36), and it was he who first identified the tiny intracellular bodies which he termed microzymas, as being the precursors of extracellular bacteria. Moreover, subsequent workers have demonstrated how micro-organisms can rapidly change their identity according to the circumstances in which they find themselves. This theory does not rule out the possibility of transmission of infectious diseases by mirco-organisms for it may well be possible for microorganisms to give rise to a specific disease condition where a general toxic (diseased) state already exists. By eliminating such organisms by means of antibiotics or artificially induced immunity, one is at best postponing the day of reckoning by leaving the toxic state to erupt later as some other disease. If one continues to suppress this with the employment of antibiotics at every sign of an acute eruptive condition (such as a rash, sore throat, cough, boils, etc.) then one is probably laying the foundation for a much more chronic and possibly degenerative condition in the future.
Moreover, Stewart (33) points out the well known fact that most of the diseases which are associated with a particular pathogenic organism may also be associated with quite different organisms. There is no invariable association of a disease with a particular organism. He also shows that even when the organisms are inoculated into various animals it is the host that determines the nature of the resulting disease if any, and he states that few species of organisms inoculated directly into the body invariably cause infection as do venereal disease and vaccination, and even then the pattern of response varies considerably.
If defensive mechanisms are suppressed (e.g. by immunosuppressive or cytotoxic drugs and presumably also by faulty nutrition) practically any micro-organism, even if normally innocuous or beneficial, can produce disease. Immunity is also dependent upon the competitive microflora of the body, and it is interesting to note that changes in diet and changes in environment are two important factors in altering this flora. Genetic constitution is certainly capable of determining susceptibility to disease.
Where reliable statistics on communicable diseases are obtainable, these are always found to be more prevalent among the lower socioeconomic groups (36), and in those countries where general conditions of hygiene, nutrition and housing have been improved there is a uniformly low prevalence of major communicable diseases (38).
Dr. Stewart (33) says that the importance of crowding, poverty and concomitant factors, as determinants of the volume and severity of infection in most countries, can be said to be enormous in terms of human suffering and inefficiency.
We have now seen that the aetiology of disease is a far more complicated matter than that of being a simple function of infection by microorganisms, and since the cause of disease is multifactorial it should not come as a surprise to find that vaccines, because they only effect one solitary aspect in this abundance of causality. are far less efficacious than has been generally thought in the past. So far the consideration has been theoretical, and it has been suggested that on theoretical grounds prophylactic vaccines cannot be expected to be very effective. The question that now confronts us is how do we measure the effectiveness of a vaccine and evaluate its usefulness in reality? There are several ways in which this is done, but in most of them there lies a flaw of sufficient magnitude as to render them highly suspect.
First let us briefly consider the method of serological determination. In this method animals are vaccinated and subsequently challenged with virulent pathogenic organisms against which the vaccine is said to give protection. The required dose of vaccine will give protection; whilst a control group of animals challenged with the same dose of micro-organism will be killed. It is perfectly true that the vaccine has provided protection and this may even amount to 100%, but to relate these findings to normal life situations is hopelessly unscientific, since natural infection never imitates the laboratory process. Outside the laboratory we just do not get inoculated with massive doses of pathogenic microorganisms. The nearest one can get to this in the natural situation is the inoculation of organisms by means of an insect or animal. Moreover, in the case of laboratory animals there is little chance of good natural immunity existing owing to the way they are bred; there is always the suspicion that they are unhealthy since they do not lead natural lives. The argument that these conditions affect controls and experimental animals alike is invalid since full health is a sine qua non of natural non-adaptive immunity but may be of little consequence in promoting a specific immune response. To come to the crunch; if microorganisms were the sole cause of disease there would be some value in using vaccines by virtue of their ability to bring about a serological conversion, but there is less sense in eliciting an immune response to a particular micro-organism if that organism is not in itself the basic cause of the disease. For this reason serological titres of antibody are equally misleading. If a vaccine elicits antibody production of adequate titre in, say, 95% of vaccines, this is quite a different thing from saying that the vaccine if 95 % effective. It would be 95 % effective if none of the vaccinees had any other protection against the organisms in question, if the organisms always caused the disease and if the antibody was effective at controlling the spread of the organism in all parts of the body and at all times in the future or at least until the reception of a booster dose of vaccine. As it is, none of these postulates can be said to be tenable. No person is without some natural, non-specific immunity, no organism has been found in nature universally to cause disease, immunity in one part of the body does not imply immunity in another, specific immunity wanes, and antigenic variations of the part of organisms renders this type of immunity increasingly ineffective. In other words, vaccinations are artificial procedures which can be found to be protective in artificial situations. What we want to know is how effective are they in the natural situation of the real world? The laboratory can tell us little about this.
Having shown the weakness of laboratory investigations we now come to look at clinical trials whereby the trend of a disease is observed after the introduction of an immunisation programme or a vaccinated group is compared with a similar control group.
In many cases vaccines appear to be effective, yet they in fact do nothing. As Dr. Stewart (33) says, "Most so-called controlled trials of vaccines fail to provide for the contingency that social change per se might have influenced a given result; improvements which followed immunisations against diphtheria, enteric and tuberculous infections occurred in each case at a time when amelioration in social and hygienic conditions contributed to a parallel diminution in these and other diseases. In this connection it can be seen from Figs 1 and 2 that diminution in mortality from typical zymotic diseases began long before any vaccination (though this is not shown for smallpox) and was more pronounced in prevaccination years than during the vaccination era.
MORTALITY FROM MEASLES, ENGLAND AND WALES 1935-1969 | |
Year | Mean deaths per million living |
1935-39 1940-44 1945-49 1950-54 1955-59 1960-64 1965-69 |
1,332 |
Fig 2 |
Figures published by the U.S. Public Health Service show clearly that the fall in the reported incidence of poliomyelitis which accompanied the introduction of the Salk vaccine had in fact begun earlier. Moreover, it was even admitted in the Journal of the American Medical Association (18) that vaccination with Salk inactivated vaccine had no significant modification on the incidence of polio. Parentally administered killed virus vaccine may fail to give protection in the gut, which is where poliovirus originally proliferates and where the typical disease of poliomyelitis takes place. One possible action of Salk vaccine is to protect against viraemia and the subsequent invasion of nervous tissue by the virus.
Because smallpox vaccination had already been practised by the middle of the 19th century the decline in that disease was said to be the result of vaccination; yet the data show that smallpox had been declining prior to the introduction of vaccination at the turn of the century, that smallpox may have quietened down as variolation decreased, and that the disease increased as vaccination increased, so that its morbidity and mortality culminated in the most serious epidemic ever recorded in 1871-2 at a time when vaccination was virtually at a maximum, and declined subsequently as vaccination declined and social conditions improved. Scarlet fever declined with no prophylactic vaccination (37)at all (and substantially before the antibiotic age); whilst whooping-cough mortality had plummeted almost to its nadir before vaccination was generally introduced in 1957.
Fig. 3 shows how similarly misleading is the popular belief concerning poliomyelitis vaccine, for once again there was certainly no increase in the downward trend in mortality after the introduction of the vaccine in this country in 1957. Nevertheless the incidence of the disease did decline rapidly, and it is probable because the Sabin oral live virus vaccine is one of the few vaccines that is administered physiologically in a similar way to the normal route of infection that it does elicit local immunity to the natural virus and may consequently help to reduce the incidence of poliomyelitis. On the other hand the same vaccine has had little effect in developing countries (39-42) where the disease tends to be widespread though often less serious; a fact which must divert our attention to reasons other than vaccination for the decline of polio in most of Europe. When it is realised that the incredible increase in poliomyelitis which took place between 1940 and 1950 was due, at least in part, to the errors of tonsillectomy (45-46) and immunisation (44-48) with alum-precipitated vaccines, it becomes much easier to undertand why polio vaccine appeared to work so well in this country and other developed countries where these procedures were once extant. A further point of interest is that cases of clinical polio have been shown not to be associated with poliovirus (49), in one study the numbers amounting to 30% of cases (50), and it is therefore likely that cases which would once have been described as poliomyelitis are now correctly ascribed to other enteric viruses which have more recently been indentified, such as some of the coxsackie viruses.
No comprehensive account of the aetiology of infectious diseases could be given within the compass of a single article, and the material so far provided has been supplied for the purpose of giving a background for a more detailed analysis of the travel requirements and need for prophylactic vaccinations prior to travelling abroad.
In the first place it should be pointed out that long distance travel, particularly if across time wnes (51), appears to provoke or trigger off a number of diseases. Although no fully documented explanation for this has yet been assembled, various factors have been implicated including the rapid change of temperature and humidity, change of diet, upsetting the biological rhythm and changes in atmospheric pressure(52).
In dealing with the question of vaccination for travel we need to consider it under two separate headings: that of international requirements and that of the individuals needs There are three.
aspects from which international requirements may be examined:
1.Safety of the vaccines used;
2.Protection of the individual and of the community;
3.Ethical considerations.
1. Safety
No vaccine is completely safe (53-55) and apart from inherent dangers there is always the risk of exogenous faults such as contaminated vaccine, contaminated needles, faulty technique or administration, reversion to virulence on the part of live attenuated organisms, or the use of wrong cultures. The dangers of various vaccinations have been quite well documented in recent years but it must be realised that the onus to report ill-effects is upon the medical profession, and few doctors have been willing to admit that vaccination has caused a death or serious disability unless absolutely unavoidable. There have been admissions on the part of doctors that even death certificates have been falsified in order to protect peoples faith in vaccination. Sir Graham Wilson (53) says that he would be unable to give a complete record of the accidents attendant on immunisation even if he had time to comb the whole of relevant literature mainly because a large number of them (and he suspected the majority) have never been reported in print. When he had access to unpublished statistics from the Ministry of Health he said he was "frankly surprised" to learn of the large numbers of persons who had died apparently as a result of attempted immunisation. Very few of these were referred to in the medical journals.
Dr. George Dick (56), Bland-Sutton Professor of Pathology at Middlesex Hospital, said that few doctors like to attribute a death or complication to a procedure which they have recommended and in which they believe.
Very little specific evidence of the long-term ill-effects and latent dangers bestowed by vaccinations has been assembled mainly because of the almost impossible task of proving that a clinical condition arising many years after a vaccination is in fact related to it. However, we know that a living virus once introduced into the body in this way can remain there quiescent for any number of years and that at any time in the future can become activated and dangerous. Moreover, it is an interesting observation that the symptoms of many diseases once thought to be caused by a virus are now known to be the result not of the replicating virus but of the specific immune response! (57).
Immunologically competent lymphocytes have been shown to destroy cells infected by virus; whereas the virus did not do so.
Looking briefly at the short-term effects of vaccinations, which are much better known and documented, even the customary triple vaccine has been shown to be followed by neurological involvement more frequently than 1:4000 (26), and severe reactions have been reported to be more frequent than 1:2,000 (58). In a study of 516,276 triples vaccinated children from l959-1965 (59), 167 cases of neurological reactions including destructive encephalopathy, convulsions, hypsarrhythmia, shock, uncontrollable screaming and serious meningitis were reported. Apart from these symptoms there were also those of skin rashes and gastrointestinal troubles.
More hazardous than the triple vaccine is that of smallpox vaccine itself, where the fatality rate ranges from about 4 per million to more than 13 per million (cf Table I). Dr. J. War m(60) quotes a fatality rate of 9 per million, which is probably high, since the average rate from table 1 is 6 per million. The risk of serious non-fatal complications from smallpox vaccination appears to vary considerably and is difficult to assess because they are often not reported as such". Conybeare (62) gives a rate of 52 per million including 13 cases per million of post-vaccinal encephalitis: whilst Herrlich (63) gives a rate of 829 per million in the Netherlands and 1.444 per million in Belgium. It is interesting to note that in 1963, when Dr Harold Jacobziner of the New York City Department of Health claimed that there were no complications from vaccination (64), no less than 398 requests were made for hyperimmune gamma-globulin for the treatment of complications (64,65). Dr. Kempes survey (64) showed that in that same year there were about 3,000 complications in a total of 14 million subjects who were vaccinated. It is worth noting that notwithstanding Dr. M. H. Smith (64) saying that our (U.S.) vaccination practice is not only obsolete but also reprehensible, and after having been appraised of Kempes findings, Dr. Jacobziner said, "In spite of Dr. Kempes questionnaire and whatever trump card he has we will go on vaccinating in New York". Whilst no one wishes to undermine anything which is of value, and certainly does not wish to prevent anyone who wishes to be vaccinated from being so, the blind fanaticism that prompts people to continue with a practice which is shown to be obsolete must be resisted at all costs.
Other diseases following vaccination are multtiple sclerosis (66,67), leukaemia (68), liver damage (69), demyelination encephalitis (70), osteomyelitis, arthritis, osteitis, basal cell carcinoma (71), diplopia and failure of vision (72).
Yellow fever vaccination is normally only required from travellers within the yellow fever belt (Fig. 5), so the average holiday-maker is not affected. A very high incidence of ill-effects was reported by Drs. Ayats and Rey in l970 (73), and these included severe protracted encephalitis, psychological disorders, major epilepsy and marked intellectual deterioration. They concluded that the risk of sequelae to post-vaccinal yellow fever encephalitis appears to be more serious than was previously thought.
It is not thought desirable to dwell upon the dangers of vaccinations at any further length here since an indication of their existence and frequency is all that should be required. As far as latent dangers are concerned, these can only be guessed at However, if a vaccine can cause encephalitis and other neurological disorders, there is little doubt that it can cause lesser (perhaps subclinical) conditions as well.
Protection of the individual and of the community.
For the most part these two factors can be considered together. It must be stated catgoriecally that successful vaccination does not guarantee any protection (61) against either disease or death from disease. In a survey of 100 consecutive smallpox patients in a British military hospital in the Middle East in 1944 Drs. Illingsworth and Oliver (74) found that 96(96%) had been vaccinated. 70% had been vaccinated within two years and 13 of the 14 who died had been vaccinated. The vaccine had been given in different places and at different times, so that there could be no question of this being the failure of a particular batch of vaccine or a particular vaccinator.
Apart from well documented evidence of failure to protect, it has always been claimed that smallpox vaccination is capable of mitigating the disease so that it is scarcely distinguishable from chicken pox (75). If this is the case, the risk of carrying the disease into the community without being recognised is all the greater. Far from acting as a protection to the community vaccination can be an additional hazard.
In this connection it is worth mentioning that nearly all the cases of smallpox which have been imported into the U.K. over the past few decades have been fully vaccinated people, as also have the few index cases which have not been imported. Tables 2 and 3 show the vaccinal state (where known) of all smallpox cases and deaths in this country from 1953 to the time of going to press. Whilst it can be argued that there has been a slight bias in favour of vaccination, this is by no means beyond dispute, not is it by any stretch of the imagination sufficient to justify any sort of legal or moral persuasion to be used to popularise the practice. In view of the fact that whilst there worth the risk involved. As far as the community is concerned, there is not the slightest doubt that the isolation of cases, surveillance of contacts (including vaccination of contracts if desired) and disinfection of contaminated material are quite adequate and have been totally successful in preventing epidemics in Europe and developed countries. The protection from vaccination in these countries has often been as low as 5% of the population; yet this has made no apparent difference to the effectiveness of modern methods of control.
TABLE 2 |
||||
Vaccination status of smallpox cases in UK from 1953-1973 |
||||
Year | No of cases | Number | Number not vaccinated | Vaccination unknown |
1953 1957 1958 1959 1960 1961/2 1966 1967 1968 1973 |
30 4 6 1 1 68 71 2 1 5 |
14 (46%) 2 (50%) 3 (50%) 1 (100%) 1 (100%) 39 (57%) 25 (35%) 2 (100%) 5 (100%) |
16 (53%) 2 (50%) 2 (33%) -- -- 25 (37%) 46 (65%) -- -- |
-- -- 1 (16%) --- --- 4 (4%) -- -- -- |
Table 3 | |||
Vaccination status of smallpox deaths in UK from 1953-1973 | |||
Year | Number of deaths | Number vaccinated | Number not vaccinated |
1953 1957 1958 1961/2 1973 |
8 2 1 25 2 |
3 (37%) 0 1 (100%) 5 (20%) 2 (100%) |
5 (63%) 2 (100%) 0 16 (80%) 0 |
In endemic areas the employment of mass vaccination may be helpful, but can never take the place of improvements in hygiene, nutriton and living conditions generally. The vaccination of travellers from non-endemic areas cannot be shown to make any useful contribution to smallpox eradication or to the maintenance of smallpox free areas. Professor Dick (61), as well as many other medical authorities, has said that it is the duty of the media to discourage mass vaccination in outbreaks of limited proportion. Vaccination for travel is simply a form of mass vaccination (as distinct from selective or discriminatory vaccination) and there is no justification for it, particularly when travellers are leaving non-endemic areas. Demands for universal vaccination of travellers after one or two cases of smallpox is grotesquely absurd and is often greatly assisted by uniformed people who recommend vaccination as a safeguard, not against smallpox, but against delays at international frontiers! On the other hand vaccination may give protection to the individual and for this reason he should be free to opt for it if he so wishes.
With regard to cholera vaccination, there are very few authorities who place much reliance upon this today, and it is almost universally agreed that cholera vaccination does not prevent the spread of epidemics. For this reason the U.S. Government ceased to require it as a condition of entry into the United States during the pandemic of el Tor cholera in 1970 (76). It is commonly known that both vaccinated and unvaccinated persons may be asymptomatic carriers and excretors of the cholera vibrio, and that they can, therefore, spread the disease where there is lack of proper hygiene and sanitation. Once again, vaccination is likely to enhance this problem rather than prevent it.
The only other disease for which there are international vaccination requirements is yellow fever, and much of what has been said in respect of smallpox is also true of this disease as far as vaccination is concerned. The chief differences are that yellow fever vaccine is possibly safer, and the immunity, so far as it exists, more solid and longer lasting. The disease is well confined to certain endemic regions, and vaccination for travel cannot be said to be of any real value in protecting members of the community in any area. Perhaps the greatest hazard is the reintroduction of the disease to areas from which it has been eradicated, and in cases of travellers emerging from endemic areas and proceeding to zones of recent eradication there might be some justification for insisting on vaccination or, alternatively, on isolation. However, the use of a mosquito net would seem to be more useful, and the eradication of the mosquito, Aedes aegypti, would remove any risk of the reintroduction of the disease for all time.
Although poliomyelitis and typhoid, together with some lesser known diseases such as tick-borne spring-summer encephalitis, Rocky Mountain spotted fever, trachoma; tularaemia and leptospirosis might be of greater hazard to a traveller than smallpox, cholera, or yellow fever; none of these diseases falls within the international regulations for vaccination. Nevertheless, it may be quite illogical for a person to be vaccinated for smallpox and not for one or more of these other diseases. By insisting on vaccination for smallpox (which can be of little value to the vast majority of travellers) authorities may unwittingly be devaluing vaccination for diseases such as poliomyelitis and typhoid, which certainly present a greater risk than smallpox.
Ethical Considerations
it is not intended to give anything other than the briefest mention of the ethical considerations regarding vaccination, since they have little place in a scientific critique or evaluation. However, it needs to be stated that many people do have ethical objections to vaccinations which are based upon religious views or upon their own personal moral principles. For many people the suffering imposed upon animals in preparing and testing vaccines is sufficient ground for ethical objection, and it seems wrong that all these people should be subjected to harassment, ridicule and unnecessary expenditure simply on account of their wish not to be vaccinated. This sort of thing has no place in a mature society and it is time we stopped behaving like scared children over a case of smallpox or cholera and accepted the obvious truth that these diseases only survive where there is lack of sanitation, undernutrition, poor accommodation, bad hygiene and fear. At the very least it should now be admitted that vaccination, whatever advantages it may have, is not a necessary condition of protecting a community from which smallpox or cholera have been removed.
Alternatives to Vaccination
Many of the alternatives to vaccination have already been mentioned or alluded to. However, the building up of good positive health is an important method of self-immunisation that should be mentioned. Some people object to the term positive health as not being precise or scientific. Moreover it is very difficult to establish the relationship between such health and resistance to disease. However, the effect of nutrition has been examined fairly closely, and results show that sound nutrition provides a very satisfactory protection against infectious diseases (78). Letyon (79) showed that prisoners of war receiving supplementary food with 30g protein had a tuberculosis rate of only 1.2% compared with 15-19% in other prisoners, Findlay (80) showed that infectious hepatitis was much more severe in malnourished persons, Hansen indicated that severe cases of herpes simplex and deaths from this disease were limited mainly to children with protein malnutrition. and various researchers have demonstrated that animals are more susceptible to various infections when undernourished. Vitamin A deficiency has been shown to be associated with the development of tuberculosis in man (81), as well as susceptibility to numerous natural infections (81) including xerophthalma. bronchopneumonia, bronchitis, pyuria, otitis media, coryza, respiratory infections and diarrhoea. More serious infections by Salmonella typhimurium have been found in rats and mice which were deficient in Vitamin A (80) than in well-fed animals. Diphtheria, staphylococcal infections and other infections have been shown to be more frequent and more serious, in infants and children who were deficient in Vitamins C (81). Space permits only a cursory glance at the effect of nutrition upon health and resistance to disease. Perhaps one of the most interesting facets of this question is that of the greater degree of health obtainable from organic grown foods as against those which are grown on soil fertilised only with nitrogen. potassium and phosphorus (N PK). In one childrens institution, the matron reported a highly significant decrease in measles after the replacement of traditional food by organically grown foods. Moreover, cases became almost entirely confined to children who had recently been admitted. All the evidence available seems to show that the healthy person is not necessarily the vaccinated one, and since vaccination does not actually increase health it is somewhat inappropriate for any one person or group of people to dictate to others in respect of the need or desirability for it.
It is unfortunate that many of those who have been most aware of the failures and limitations of vaccination have failed to take the whole picture into account and in consequence have set out with only one intention: namely to amass statistics showing the futility of vaccination to the exclusion of any data which show favourable results. In consequence they have often made categorical statements which have not been supported by the data available, and have been guilty of emotionalism and exaggeration. This was largely the result of measures to enforce compulsion. and in many countries where people probably set less value on liberty than we do in Britain compulsory vaccination for several diseases is still enforced, and this undoubtedly reflects upon international policies. This, in turn, continues to fan the fires of emotionalism, and since it cannot be shown that any of these countries has a better health record (as far as the respective diseases for which vaccination are concerned) than we have here in the U.K. it would seem that the sooner these countries abandoned their medieval approach to the problem the better off we would all be and the sooner our right to travel unhindered would be vindicated.
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