669LEADING ARTICLES

Influenza

THE LANCETLONDON 21 SEPTEMBER 1968

WORKERS at the Common Cold Research Unit havebeen using challenge with influenza virus in volunteersas a method of assessing the efficacy of vaccines andantiviral agents.2 This technique promises a consider-able advance in methods of studying protection againstinfluenza. Large field trials are the ultimate way of

demonstrating the worth of a vaccine, but they are verydifficult to organise because of the uncertainty thatinfluenza of a strain related to the vaccine will appear ina susceptible population. When this does happen, killedaqueous influenza vaccines are found to reduce theincidence of influenza by about 65%.3 The currentvaccines are not ideal: the immunity they confer is

incomplete, they have to be given by injection, and theysometimes produce local and general reactions, althoughthese have decreased as better-purified vaccines haveemerged. The vaccines take a long time to prepare, andwhen large amounts are required to meet an impendingepidemic sufficient vaccine is rarely available in time tooffer worthwhile community (as opposed to individual)protection. Improvements in vaccines have thereforebeen sought. The use of an oily adjuvant was found togive higher and longer-sustained antibody levels 4 andfewer immediate reactions; and it offered a promisinganswer to the supply problem in the face of an epidemic,since it enabled good antibody titres to be secured withless antigen. Unfortunately, however, this vaccine

produced severe reactions with tracking abscesses in afew individuals, and it has therefore been withdrawn.The cause of these reactions is unknown, but they may berelated to impurities in the vaccine; so purification hasbeen an aim in vaccine development. One approach isto produce purified whole virus-for example, by thetechnique of density-gradient centrifugation-and an-other is to fractionate the virus with ether, deoxycholate,or other fat solvent. The fractionated hxmagglutininvaccine produces circulating antibodies in man,5 butunlike oily adjuvant vaccine 6 it has not yet been shownto protect against the disease. The work of the M.R.C.influenza-vaccine committee has shown that attenuatedliving influenza vaccine given intranasally usually pro-1. Beare, A. S., Hobson, D., Reed, S. E., Tyrrell, D. A. J. Lancet, Aug.

24, 1968, p. 418.2. Medical Research Council Annual Report, April, 1967-March, 1968;

p. 18. H.M. Stationery Office.3. Medical Research Council Committee. Br. med. J. 1958, i, 415.4. Hobson, D., Lane, C. A., Beare, A. S. ibid. 1964, ii, 271.5. Duxbury, A. E., Hantson, A. W., Sievers, J. G. M. J. Immun. 1968,

101, 62.6. Medical Research Council Committee. Br. med. J. 1964, ii, 267.

duces poor circulating antibody levels, but gives a betterprotection against challenge 1 than killed influenza vaccinegiven by injection. The situation is somewhat similar tothat with killed and attenuated poliovaccine and gutimmunity, but the difference is that influenza is due tothe multiplication of virus in the respiratory tract, where-as in poliomyelitis the virus has to spread from the gut tothe central nervous system to cause disease, so that therole of the circulating antibody in clinical immunity isgreater. The reason for the superiority of the livingvaccine is probably the local production of IgA antibodyin the respiratory tract. These findings suggest that theintranasal or aerosol administration of living vaccine maybe a means of influenza control, as has long been con-tended by Russian investigators. Unfortunately, as thework of BEARE and his colleagues 1 illustrates, we knowinsufficient about the means of attenuating strains ofinfluenza or measuring the degree of attenuationachieved. MANN et al. have found that killed influenzavaccine given up the nose evokes local antibody 8 andaffords protection.9 It may be that killed vaccine givenintranasally will prove to be the answer, since it over-comes the difficulties of attenuation; and this approachis under investigation at the Common Cold ResearchUnit.i

Challenge in volunteers can also be used to evaluateantiviral agents, although the dose needs careful adjust-ment so that a small effect is not swamped by a virus doseunlikely to be met in Nature. Although there is no reallyeffective agent yet available, the actions of amantadinehydrochloride 10 against some strains and of an iso-quinoline (UK 2371, Pfizer) are encouraging. 2 Theinterferon inducers 11 are also good prospects for futurecontrol of influenza. At present, however, aqueouskilled vaccine by injection is the only sure method ofprevention.

This year could well see an epidemic in Britain, sincethe disease has been prevalent in the southern hemisphere,where the strain is the influenza A2 first isolated in

Tokyo in 1967 and similar to those prevalent in Englandin 1966. More recently a distinct antigenic variant of A2has been reported from Hong Kong and Singapore.This variant differs more widely from other A2 strainsthan any previously isolated, and some workers wouldchoose to classify it as A3. But, since low levels of anti-body to the Hong Kong strain have been found in peoplewho have had A2 influenza and in some who havereceived current influenza vaccine, the decision is that itshould be called an A2 strain.l2 Either or both of thesestrains may well reach this country in the coming months.At present the supplies of vaccine available in U.K.contain influenza A2 strains likely to afford protectionagainst strains now prevalent in Australia and elsewhere7. Beare, A. S., Hobson, D., Howells, C. H. L., Pereira, M. S., Pollock,

T. M., Tyler, L. E., Tyrrell, D. A. J. J. Hyg., Camb. (in thepress).

8. Mann, J. J., Waldman, R. H., Togo, Y., Heiner, G. G., Dawkins, A. T.,Kasel, J. A. J. Immun. 1968, 100, 726.

9. Waldman, R. H. 1st International Congress on Virology, Helsinki, 1968.10. See Lancet, 1967, ii, 708.11. See ibid. 1968, i, 461.12. National Communicable Diseases Centre Morbidity and Mortality

Weekly Report, Aug. 31, 1968, p. 323.

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in the southern hemisphere, but vaccines including the1968 Hong Kong A2 strains are not yet available. Thebest course seems to be to follow the recommendationsof the U.S. Public Health Service advisory committeeon immunisation practices —namely, to use existingkilled vaccine for people in serious risk of dying if theycatch influenza and, later, when a monovalent vaccineagainst the new strain is available, these patients couldbe revaccinated and the new vaccine could also beoffered for wider use.

Alcohol and the LiverOVER the past twenty-five years the widely accepted

view has been that the hepatic injury in alcoholism isthe outcome of nutritional deficiencies. The alcoholic

literally runs on spirit and requires few calories fromother sources. Recent work by TYGSTRUP and his

group 1 has shown that the human liver can metaboliseamounts of alcohol which would produce at least 1050calories per twenty-four hours-a third of the averagedaily need. Moreover, the alcoholic often prefers tospend what money he has on alcohol rather than on thealmost equally costly, but more valuable, protein foodsand vitamin supplements. This nutritional basis wasidentified in the 1940s by experiments largely done inrats. In this animal, fatty change, fibrosis, and micro-nodular cirrhosis can be readily induced by a low-choline, low-protein diet.2 In recent years, however,doubts have arisen whether malnutrition is the truecause.3 The human alcoholic has not only fatty changeand fibrosis in the liver, but also, after heavy drinking, avery profound hepatitis, which is apparent in focalnecrosis of liver cells, related polymorph infiltration,and deposits in the liver cell of a dense eosinophilicmaterial, the alcoholic hyalin of MALLORY .4 5 This

picture of hepatitis has never been produced in

laboratory animals, however large the volume ofalcohol fed.

Important papers by RUBIN and LIEBER 6 from theMount Sinai and Cornell Universities, New York, nowseem to prove that alcohol is directly poisonous to theliver. 5 alcoholic volunteers were given alcohol and anadequate high-protein low-fat diet for eighteen days. In

every case fat accumulated in the liver cell, and ultra-structural changes were observed by the electron

microscope. In a second study, more detailed observa-tions were made on young non-alcoholic volunteers.Alcohol was substituted isocalorically for carbohydratein the diet. Fatty change and ultrastructural changeswere seen in the liver when alcohol was given, both withthe standard diet and with the diet high in protein

1. Tygstrup, N. B., et al. Meeting of International Association for Studyof the Liver, Karlovy Vary, Czechoslovakia, 1968.

2. Hartroft, W. S. in Progress in Liver Disease (edited by H. Popper andF. Schaffner); vol. I. New York, 1961.

3. Rubin, E., Lieber, C. S. Am. J. Med. 1968, 45, 1.4. Phillips, G. B., Davidson, C. S. Archs intern. Med. 1954, 94, 585.5. Edmondson, H. A., Peters, R. L., Reynolds, T. B., Kuzma, O. T. Ann.

intern. Med. 1963, 59, 646.6. Lieber, C. S., Rubin, E. Am. J. Med. 1968, 44, 200.7. Rubin, E., Lieber, C. S. New Engl. J. Med. 1968, 278, 869.

and low in fat. The ultrastructural changes in theliver were particularly interesting. Lipid dropletsappeared in the liver cells and the smooth endoplasmicreticulum increased. This organelle contains the

enzymes concerned with the metabolism of alcohol,and an increase could be interpreted as an inductionby alcohol of the enzymes required for its metabolism.8Mitochondria were enlarged and distorted. The

rough endoplasmic reticulum was vesiculated with

irregular ribosomes on the membranes. Although thepatients had some of the symptoms of alcohol excess,such as headache, nausea, and sometimes euphoria,speech was not slurred and they were not ataxic:

clinically they could not be regarded as drunk. More-

over, blood-alcohol levels fluctuated between 20 and80 mg. per 100 ml., usually being about 50 (the breatha-lyser test is " positive

" over 80). Variable quantities

of alcohol were consumed : the lowest to cause fat toaccumulate in the liver was 18 ounces of an 86-proofalcoholic beverage on the first day and 24 ounces on thesecond day. When, in 1 subject, alcohol was substi-tuted isocalorically for carbohydrate, fatty changefollowed 7 ounces of 86-proof alcohol for four days,10 ounces for two more days, and 13 for another two.These are quantities consumed not only by alcoholicsbut by many persons who would not generally beregarded in this light. If this is the case, and if the liver

damage described by RUBIN and LEIBER 6 I might lead tocirrhosis, then why are there not more cirrhotics in theworld, particularly among those with higher incomes?Genetic and constitutional predisposition must clearlybe investigated further.The role of nutritional deficiency (particularly of

protein and choline) in the genesis of the hepaticchanges must not be entirely discredited. Hepaticchanges cannot be induced in laboratory animals byfeeding alcohol alone. 9 Some years ago, PHILLIPS andothers 10 withdrew alcohol from 3 alcoholic subjectsand put them to bed. None of them showed improve-ment in function, size, or fat content of the liver inthe eighteen days during which they received a purifiedlow-protein diet but all improved after eight to ten dayson an adequate diet. This finding seems to indicatethat alcohol is not the only factor concerned. SuMMER-SKILL et al.11 gave 7 chronic alcoholics, with liverdisease and malnutrition, 90-120 ml. of 95% alcoholdaily for ten to thirty-two days. In 3 the dietaryprotein was only 25 g. a day. Appetite and body-weight improved. Liver biopsy specimens and bio-chemical changes indicated no adverse effects. Theseworkers even suggested that alcohol may have a place inthe treatment of chronic alcoholics with liver disease. Inanother inquiry by LEEVY and TEN HOVE 12 on alcoholicsubjects who volunteered, large quantities of alcohol werecontinued but an adequate diet was added. Improvement8. Lieber, C. S., Rubin, E. Gastroenterology, 1968, 54, 642.9. Moon, V. H. Archs Path. 1934, 18, 381.

10. Phillips, G. B., Gabuzba, G. J., Jr., Davidson, C. S. J. clin. Invest.1952, 31, 351.

11. Summerskill, W. H. J., Wolfe, S. J., Davidson, C. S: Lancet, 1957,i, 335.

12. Leevy, C. M., Ten Hove, W. in Biochemical Factors in Alcoholism(in the press).