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THE INFLUENZA VIRUS IN RELATION TO PROPHYLAXIS AND TREATMENT
THE INFLUENZA VIRUS IN RELATION TO PROPHYLAXIS AND TREATMENT
27
the British workers, so that it would appear that epidemic influenza is produced by one and the same virus in different parts of the world. The virus hypothesis, to quote LAIDLAW’S words, is " already transformed into
Hampstead by
THE LANCET
theorem." What is the practical significance of this ? The clinical observation that one attack of influenza in man does not leave a lasting immunity, and the lack of success which has attended attempts at serum therapy in virus infections might well suggest that these discoveries while of immense scientific interest may be of little material value in the control or treatment of epidemic influenza. That such a hasty conclusion would be quite unjustified at this stage is clear from the two new papers dealing with immunological problems of experimental influenza just published by the Hampstead team.4The ferret, they find, as the result of recovery from infection with influenza virus, becomes immune to reinfection ; specific antibody is present in its blood. But after an interval of a few months this immunity wanes, the antibody titre falls, and the animal becomes susceptible- to reinfection. It is important to note that the ferret becomes susceptible again despite the presence of some circulating antibody, and that its immunity can be restored by the inoculation of virus subcutaneously, a non-infective route. Now random sampling of human sera has shown that the very great majority contain antibody for the virus, presumably as the result of previous infection, and it seems just possible that, as in the ferret, the immunity possessed by humans could be reinforced by prophylactic inoculation. In this way it be possible to tide individuals over the period of epidemics of influenza. Another of from which these point importance emerges recent studies of influenzal immunity is that the antiserum made in the horse seems to possess some therapeutic value when tested in the mouse. When serum is given along with virus, infection But can be prevented ; that was to be expected. the astonishing thing is that even when given 48 hours after infection, this serum exerted a quite definite effect on the course of infection, as In was evidenced by the reduced mortality-rate. a
LONDON: SATURDAY, JULY 6, 193ó
THE INFLUENZA VIRUS IN RELATION TO PROPHYLAXIS AND TREATMENT IF there
are
any who
are
still
truly
in doubt
whether the prime cause of epidemic influenza is a filtrable virus, let them read the Linacre lecture delivered recently by Sir PATRICK LAIDLAW, F.R.S.l They will find there set out with admirable clearness the evidence which LAIDLAW and his colleagues, C. H. ANDREWES and WILSON SMITH, have produced in support of the virus hypothesis. It is a record of brilliant work which makes a most convincing story, the more so because of the restraint with which it is told, and because of the scrupulous care with which each fact has been weighed and examined before being accepted. The history of the virus hypothesis of the cause of influenza falls naturally into two periods. Prior to 1933 the only available experimental animal was man, on whom the hypothesis could not be adequately tested, and though evidence had been obtained in support of the virus theory, it fell far short of convincing proof. In 1933 came the important announcement in our columns by SMITH, ANDREWES, and LAIDLAW2 that the ferret was susceptible to influenza. A new era in influenza research was inaugurated and the march of events has been rapid. The demonstration in 1933 that a filtrable virus is present in the nasopharynx of early cases of epidemic influenza and that specific antibodies can be demonstrated in the blood of human and ferret convalescents was soon followed by the discovery that the mouse is susceptible to the influenza virus and that it is possible to prepare a specific antiserum in the horse.3 The group of workers at Hampstead were now in a position to isolate and type viruses from subsequent cases of influenza. The year 1934 proved disappointing inasmuch as there was no widespread epidemic of influenza in London from which to obtain material, but the one strain isolated was shown to be identical with the 1933 strain. In the winter of 1934-35 eight new strains were obtained, six from an outbreak in Shorncliffe and two from the London area ; these again, though not yet completely investigated, seem to be identical with those previously isolated. Added to this comes evidence from America where Dr. T. FRANCIS, Jun., working at the Rockefeller Institute, has isolated two strains of influenza virus, one from an outbreak at Porto Rico and one from Philadelphia in 1935. Both these strains are neutralised by the specific antiserum made at 1 Laidlaw, P. P.: THE LANCET, 1935, i., 1118. C. H., and Laidlaw: Ibid., 1933, ii.,
2 Smith, W., Andrewes,
66.
3 Andrewes, Laidlaw,
and Smith :
Ibid., 1934, ii., 859.
might
even three days appreciable effect. The authors are naturally chary in forecasting the value of this serum used therapeutically in man, but the prospect that a serum of such a high
one
experiment
serum
after infection had
given
an
potency may be of use in the treatment of influenzal pneumonia seems sufficiently likely to make its clinical trial an exciting adventure. THE SINGER’S NODULE THE little nodule which makes its appearance the vocal cord is never a danger to life or health, but is of serious importance to professional voiceusers whose means of livelihood it may destroy for a prolonged period or even permanently. In England it is usually called the " singer’s nodule," on
4 Laidlaw, Smith, and Andrewes: Brit. Jour. Exp. Path., June, 1935, p. 275. 5 Smith, Andrewes, and Laidlaw: Ibid., June, 1935, p. 291.
27
the British workers, so that it would appear that epidemic influenza is produced by one and the same virus in different parts of the world. The virus hypothesis, to quote LAIDLAW’S words, is " already transformed into
Hampstead by
THE LANCET
theorem." What is the practical significance of this ? The clinical observation that one attack of influenza in man does not leave a lasting immunity, and the lack of success which has attended attempts at serum therapy in virus infections might well suggest that these discoveries while of immense scientific interest may be of little material value in the control or treatment of epidemic influenza. That such a hasty conclusion would be quite unjustified at this stage is clear from the two new papers dealing with immunological problems of experimental influenza just published by the Hampstead team.4The ferret, they find, as the result of recovery from infection with influenza virus, becomes immune to reinfection ; specific antibody is present in its blood. But after an interval of a few months this immunity wanes, the antibody titre falls, and the animal becomes susceptible- to reinfection. It is important to note that the ferret becomes susceptible again despite the presence of some circulating antibody, and that its immunity can be restored by the inoculation of virus subcutaneously, a non-infective route. Now random sampling of human sera has shown that the very great majority contain antibody for the virus, presumably as the result of previous infection, and it seems just possible that, as in the ferret, the immunity possessed by humans could be reinforced by prophylactic inoculation. In this way it be possible to tide individuals over the period of epidemics of influenza. Another of from which these point importance emerges recent studies of influenzal immunity is that the antiserum made in the horse seems to possess some therapeutic value when tested in the mouse. When serum is given along with virus, infection But can be prevented ; that was to be expected. the astonishing thing is that even when given 48 hours after infection, this serum exerted a quite definite effect on the course of infection, as In was evidenced by the reduced mortality-rate. a
LONDON: SATURDAY, JULY 6, 193ó
THE INFLUENZA VIRUS IN RELATION TO PROPHYLAXIS AND TREATMENT IF there
are
any who
are
still
truly
in doubt
whether the prime cause of epidemic influenza is a filtrable virus, let them read the Linacre lecture delivered recently by Sir PATRICK LAIDLAW, F.R.S.l They will find there set out with admirable clearness the evidence which LAIDLAW and his colleagues, C. H. ANDREWES and WILSON SMITH, have produced in support of the virus hypothesis. It is a record of brilliant work which makes a most convincing story, the more so because of the restraint with which it is told, and because of the scrupulous care with which each fact has been weighed and examined before being accepted. The history of the virus hypothesis of the cause of influenza falls naturally into two periods. Prior to 1933 the only available experimental animal was man, on whom the hypothesis could not be adequately tested, and though evidence had been obtained in support of the virus theory, it fell far short of convincing proof. In 1933 came the important announcement in our columns by SMITH, ANDREWES, and LAIDLAW2 that the ferret was susceptible to influenza. A new era in influenza research was inaugurated and the march of events has been rapid. The demonstration in 1933 that a filtrable virus is present in the nasopharynx of early cases of epidemic influenza and that specific antibodies can be demonstrated in the blood of human and ferret convalescents was soon followed by the discovery that the mouse is susceptible to the influenza virus and that it is possible to prepare a specific antiserum in the horse.3 The group of workers at Hampstead were now in a position to isolate and type viruses from subsequent cases of influenza. The year 1934 proved disappointing inasmuch as there was no widespread epidemic of influenza in London from which to obtain material, but the one strain isolated was shown to be identical with the 1933 strain. In the winter of 1934-35 eight new strains were obtained, six from an outbreak in Shorncliffe and two from the London area ; these again, though not yet completely investigated, seem to be identical with those previously isolated. Added to this comes evidence from America where Dr. T. FRANCIS, Jun., working at the Rockefeller Institute, has isolated two strains of influenza virus, one from an outbreak at Porto Rico and one from Philadelphia in 1935. Both these strains are neutralised by the specific antiserum made at 1 Laidlaw, P. P.: THE LANCET, 1935, i., 1118. C. H., and Laidlaw: Ibid., 1933, ii.,
2 Smith, W., Andrewes,
66.
3 Andrewes, Laidlaw,
and Smith :
Ibid., 1934, ii., 859.
might
even three days appreciable effect. The authors are naturally chary in forecasting the value of this serum used therapeutically in man, but the prospect that a serum of such a high
one
experiment
serum
after infection had
given
an
potency may be of use in the treatment of influenzal pneumonia seems sufficiently likely to make its clinical trial an exciting adventure. THE SINGER’S NODULE THE little nodule which makes its appearance the vocal cord is never a danger to life or health, but is of serious importance to professional voiceusers whose means of livelihood it may destroy for a prolonged period or even permanently. In England it is usually called the " singer’s nodule," on
4 Laidlaw, Smith, and Andrewes: Brit. Jour. Exp. Path., June, 1935, p. 275. 5 Smith, Andrewes, and Laidlaw: Ibid., June, 1935, p. 291.