UNITED NATIONS
NATIONS UNIES
W O R L D
H E A L T H
ORGANISATION
MONDIALE
O R G A N I Z A T I O N
DELASANTÉ
EXPERT GCMMITTEE ON YELLOT EEVER Second Session Kampala, 14-19 September 1953
W H O A F / 2 1 l'" 26 August 1953 ORIGINAL: ENGLISH
THE C a i D I I E D USE OF THS VIRUSES OF YELLaV FEVER Aî© VACCINIA BY THE SCPtATCn ISTHOD FOR IMUNIZr^TION A G A I I T S T Y E L L 0 ¥ FEVER AND SiilLLPOX by Dr. G. STU/iRT
The combined use of these two viruses by the Scratch method f o r mass immunization was f i r s t proposed by PELTIER, DURIEUX, JONCHERE and ARQUIE '^'^ (1939, 1940), a f t e r they had found that the a p p l i c a t i o n of the French neurotropic s t r a i n of y e l l o w ^ e v e r v i r u s to cutaneous s c a r i f i c a t i o n s r e s u l t e d i n the development of immunity to yellow f e v e r , and a f t e r they had established proof that by t h i s method vaccination against both yellow fever and smallpox could be performed simultaneously without accident. Acceptance of the proposal by the French A u t h o r i t i e s l e d
successively to the a d m i n i s t r a t i o n , by cutaneous a p p l i c a t i o n , of t h i s combined yellow-fever-smallpox vaccine to 100,000 inhabitants of Senegal i n 1939, to c e r t a i n of the m i l i t a r y and c i v i l i a n inhabitants of the t e r r i t o r y of French West A f r i c a i n 1941, to 14,330,735 of the t o t a l population i n that t e r r i t o r y (approximately 16 m i l l i o n ) betv/een 1942 a d 1946, 1948 (PELTIER,^'^ 1947, 1948). The yellovz-fever v i r u s component of the combined vaccine i s made from the brains of mice infected with neurotropic yellow-fever v i r u s at i t s 256th - 258th passage through mice (PELTIER, and mixed v/ith s t e r i l e volvmies). 1946). A f t e r d e s i c c a t i o n , the mouse b r a i n s are ground up and to 17,000,000 inhabitants of that t e r r i t o i y by '
i n e r t powder ( b r a i n powder - 1 volume, i n e r t powder - 2
/ i f t e r dehydration, the powder i s d i s t r i b u t e d i n ampoules, each The a n t i v a r i o l o u s component i s
containing l / l O of a b r a i n = 100 doses of vaccine. d r i e d smallpox vaccine.
For use, the two components are placed i n a mortar and
mixed together before adding 2 cc of n e u t r a l s t e r i l e gum arabic s o l u t i o n f o r f u r t h e r mixing. Of the r e s u l t a n t suspension 2 drops are placed on the s k i n i n the d e l t o i d
region and through each drop two p a r a l l e l s c a r i f i c a t i o n s are made, each 0,5 cm i n length. The gum d r i e s and provides a protective covering.
WHOAF/21 page 2 This combined vaccine, because of i t s demonstrated effectiveness, i t s ease of administration, and i t s low cost of production and application, has proved highDy successful i n meeting the requirements of such a campaign as that waged i n French West A f r i c a , which has entailed vaccination of the entire population of that t e r r i t o r y w i t h the two viruses administered simultaneously, once every four years, " i n order to insure immunity i n a l l the newborn and to re-immunize any persons who may have l o s t t h e i r immunity to either v i r u s " . (SMITHBURN,'^'^ 1951). measures ever put into e f f e c t " . Because of the f a c t , however, that the yellow-fever virus component of t h i s combined vaccine contains, as antigen, a s t r a i n of yellow-fever virus with highly developed neurotropism, certain workers have considered i t s use to constitute the potential hazards f o r humem immunization, p a r t i c u l a r l y f o r children (e.g. serious postvaccination reactions involving the central nervous system). In consequence, with a view to replacing, i f possible, t h i s neurotropic virus by one which had been rendered essentially avirulent, neurotropically as well as v i s c e r o t r o p i c a l l y , while s t i l l retaining i n large measure i t s antigenic potency, investigations into the p o s s i b i l i t y of employing 17D virus by scratch were commenced i n 1947 at the Yellow Fever Research Institute i n Lagos, Nigeria. Once the immunizing power of 17D vaccine administered DICKJ" 1 9 5 2 ) ,
This campaign has been described by
SMITH^ (1951) as being "highly successful" and "one of the most ambitious public h e a l t h
by s c a r i f i c a t i o n had been established by several experiments (HAHN,-^ 1951,* application.
H A H N ^ (1951) developed a combined yellow-fever - smallpox vaccine f o r cutaneous The 17D component of the vaccine i s prepared i n the usual way to the a 50 per cent solution of gum arabic stage of homogenizing the infected chick embryos; volume of phenolized vaccine lynphj ampoules i n amounts of 0.5 or 1 cc. attached to a desiccator;
i s then added to give a f i n a l concentration of gum of 15 per cent, followed by l / 5 t h the combined product is now mixed and dispensed i n t o The ampoules are then rapidly s h e l l frozen and A f t e r reconstitution i n 0.5 or 1,0 cc of
a f t e r 24 hours' desiccation, they are f i l l e d with diy
nitrogen, sealed o f f and stored at 0°G. allowed to stand f o r 15-30 minutes. a drop on the arm s k i n ;
d i s t i l l e d water, as the case may be, the reconstituted vaccine i s mixed thoroughly and Pasteur pipettes are used f o r mixing and placing 2 scratches 6 - 8 m long are then made through the drop.
The protection afforded by s c a r i f i c a t i o n with 17D virus i s evidenced by the results and reported by HAHN^ (1951). During a f i e l d t r i a l at Kumbo-Fiango, B r i t i s h Cameroons,
WHOAF/21 page 3 4,431 of a t o t a l population of 5,368 were vaccinated - 3,808 by scratch, 623 by subcutaneous inoculation. inoculation. test. Three months after the vaccinations, an attempt was made to secure sera from the ice i n question, but only 67 could be located, of whom 41 had been vaccinated by scratch and 26 by injection. Of the 41 vaccinated by s c a r i f i c a t i o n , 38 gave a positive protection t e s t : i.e. 92.7^ Of the 26 vaccinated by subcutaneous inoculation, 23 had a positive protection test: Blood specimens were obtained from 116 persons immediately before vaccination; of that number 77 were vaccinated by scratch, 39 by subcutaneous Of the total 116 pre-vaccination sera, 102 gave a negative protection
i . e . 88.5^. Later, a further 68 blood specimens were secured from persons vaccinated by the scratch method, and of that number, 65 or 95.6^ gave a positive protection test; 20 or 87^ gave a positive protection test. Further evidence i n this respect i s adduced by DICK^ (1952), who, i n Uganda, compared the immunity response following the administration of (a) the Dakar vaccine by scratch, (b) the 17D vaccine by subcutaneous inoculation and (c) the 17D vaccine by scratch. Among groups of volunteers, who were found to have no demonstrable yellowfever antibody prior to vaccination and whose post-vaccination sera were available f o r examination 28 to 32 days after vaccination: (a) (b) 55"out of 56 vaccinated with Dakar vaccino developed protective antibody, i.e. 98.2^ 64 out of 68 vaccinated with 17D vaccine by subcutaneous inoculation developed protective antibody, i.e. 94.1^; and (c) 85 out çf 91 vaccinated with 17D vaccine by scratch developed protective antibody, also, of 23 further blood specimens taken frora persons vaccinated by subcutaneous inoculation,
i .e. 93.4^. In so far as the immunity response to the administration by s c a r i f i c a t i o n of the yellow-fever virus component i n Hahn's combined vaccine i s concerned, HAHN^ (1951) reported that i n one experiment, i n yàiich his mixed 17D yellow-fever-vaccinia vaccine was employed, 12 out of 12, i . e . 100^ of those vaccinated, who had had negative pre-
WHO/YF/21 page 4
vaccination sera, developed yellow-fever antibody by the sixth week after v a c c i n a t i o n . On the other hand, when a combined vaccine similar to that of Hahn was a l i k e percentage of antibody response to the yellow-fever virus component. In t h i s study the vaccines employed were; (a) the yellow-fever vaccine was *
administered
by s c a r i f i c a t i o n to a selected group i n Uganda, DICK and HORGAN^ (1952) f a i l e d to f i n d
one
prepared i n the laboratories of the International Health D i v i s i o n of the R o c k e f e l l e r Foundation, New York and was that used by Dlok i n his experiments recorded above; (b) the vaccinia virus was the standard calf lymph prepared at the Medical Research Laboratory, Nairobi, Kenya; concentration of 0,5^. i t was suspended i n a 50^ g l y c e r o l with phenol i n a f i n a l I t was A gum arabic solution was used to suspend the 17D v i r u s and
the smallpox vaccine f o r combined application by the s c a r i f i c a t i o n technique.
also used to suspend the c a l f lymph i n another part of the experiments (see below). F i f t y African women were made available f o r the test and placed i n two groups of 25 each. Group I . Tests were carried out as follows: The contents of 1 ampoule of yellow-fever vaccine were rehydrated Jn a mixture 0,02 ml of this mixture was delivered from a
1.0 ml of the gum arabic solution and 1,0 ml of calf lymph, and thoroughly mixed i n a mortar, with the aid of a pestle, women included i n this group. made through each drop. Group I I . Each of the 25 women i n this group were inoculated subcutaneously with 0,5 ml of the contents of 1 ampoule of the yellow-fever vaccine suspended i n 50 ml of d i s t i l l e d water, and each was then immediately vaccinated at the same s i t e by s c a r i f i c a t i o n , following the method described above, with 0,02 ml of a mixture of c a l f lymph and 1,0 of the gum arabic solution. Results! Among those who had been found to have no demonstrable yellow-fever ml tuberculin syringe as 2 drops on to the d e l t o i d region of the arm of each of the 25 Two s c a r i f i c a t i o n s , each approximately 1 cm l o n g , were
antibody p r i o r to vaccination and whose post-vaccination sera were available 38 days after vaccination: In Group 1,14 out of 21 s c a r i f i e d with the mixed vaccine had by that time developed yellow-fever antibody, i.e. 66,7/oj '
WHOAL/21 page 5 In Group I I , 22 out of 22 i n o c u l a t e d subcutaneously w i t h 17D vaccine and t h e n v a c c i n a t e d by s c a r i f i c a t i o n w i t h a mixture of c a l f lymph and gum a r a b i c s o l u t i o n had by that time developed y e l l o w - f e v e r antibody, i . e . 100^. In regard t o those i n Group I whose sera were negative 28 days a f t e r v a c c i n a t i o n , a l l 7 were again, b l e d two'months l a t e r , but none o f them had developed p o s i t i v e sera ' by t h a t time. *
Thus, whereas Hahn found t h a t , f o l l o w i n g the a d m i n i s t r a t i o n by s c r a t c h of h i s mixed y e l l o w - f e v e r v a c c i n i a v a c c i n e , 100^ of those so v a c c i n a t e d developed y e l l o w - f e v e r a n t i b o d y by the s i x t h week a f t e r v a c c i n a t i o n , Dick and Horgan found that only 66% of those who were s c a r i f i e d w i t h t h e i r mixed vaccine had by t h a t time developed y e l l o w fever antibody. Although, . .
i n connexion w i t h these divergent r e s u l t s , there were d i f f e r e n c e s i n the
p r e p a r a t i o n s employed, i t i s noteworthy t h a t i n Dick's previous experiments i n Uganda to which reference has been already made i n t h i s paper - s c a r i f i c a t i o n w i t h 17D vaccine
alone, u s i n g the same batch as i n the combined vaccine of Dick and Horgan mentioned above, had immunized 93.4^ of those vaccinated. Moreover, from experiments d e s c r i b e d i n t h e i r
paper by DICK and HORGAN^ (1952), i t was concluded t h a t any s i g n i f i c a n t r e d u c t i o n i n the t i t r e of the 17D v i r u s component g l y c e r o l or gum i n t h e i r combined vaccine due t o contact w i t h phenol,
arabic i n the concentrations present and under the c o n d i t i o n s of t h e i r These authors suggest t h a t the d i f f e r e n c e i n the immunity
study was very u n l i k e l y .
response of the two groups i n t h e i r study may be due t o some l o c a l f a c t o r which prevented invasion of s u s c e p t i b l e c e l l s o f the s k i n by the 17D vaccine v i r u s i n some cases. results of t h e i r study l e d these authors t o the f o l l o w i n g c o n c l u s i o n i The
"while there is
good evidence f o r the e f f i c i e n c y of 17D vaccine as an immunizing agent when administered by s c a r i f i c a t i o n (HAHN^ 1951; DICK''" 1952), the present study i n d i c a t e s t h a t the
percentage of those vrtio became immune a f t e r v a c c i n a t i o n w i t h the mixed vaccine used in this t r i a l i s not s u f f i c i e n t l y high t o s\;iggest t h a t t h i s type of mixed vaccine should be used r o u t i n e l y " . On the other hand, " i f Hahn's r e s u l t s are confirmed, then i t would
seem that a h i g h l y e f f i c i e n t mixed vaccine i s a v a i l a b l e f o r use". F i n a l l y i t may be mentioned that i n the groups v a c c i n a t e d by Hahn and by Dick and
Horgan w i t h a mixed v a c c i n e , there was no evidence t h a t the y e l l o w - f e v e r v i r u s component had i n t e r f e r e d w i t h the v a c c i n i a ' v i r u s component. In n e i t h e r s e r i e s was there ary post-
v a c c i n a t i o n r e a c t i o n i n v o l v i n g the c e n t r a l nervous system.
WHO/rL/21 page 6 REFERENCES 1. DICK, G.W.A, (1952) A preljiminary evaluation of the immunizing power of chick-embryo 17D yellow-fever vaccine inoculated by s c a r i f i c a t i o n . Amer. J . Hyg., 55: 140-153. and HORGAN, E . S . (1952) Vaccination by s c a r i f i c a t i o n with a combined 17D yellow-fever and vaccinia vaccine. J . Hyg., 50; 376 -383. HAHN, R.G. (1951) application. A combined yellow fever - smallpox vaccine f o r cutaneous Amer. J . Hyg., 54; 50-70.
2. 3. 4. 5.
PELTIER, M. (1946) Preparation of yellow-fever vaccine produced by Pasteur I n s t i t u t e , Dakar, UNRRA Epidemiol. Inf. B u l l . , 2: 806-808. (1947) Yellow fever vaccination, simple or associated with vaccination against smallpox, of populations of French West A f r i c a by method of Pasteur Institute of Dakar. Amer. J . Pub. Health, 37: 1026-1032.
^' 7.
TZTT ^^'^^^^ amariles par l a
^^^^^^ antiamaril et vaccinations antiamariles et a n t i v a r i o l o méthode dakaroise en Afrique occidentale f r a n ç a i s e . Proc. Internat. Gong. Trop. Med. & Malaria, I : 489-497. xxançaise. — DURIEUX, C , JONCHERE H & ARQUIE, E . (1939) P é n é t r a t i o n du virus amaril neurotrope par voie cutaneej vaccination mixte contre l a f i è v r e iaune et l a v a r i o l e ; note p r é l i m i n a i r e . B u l l . Acad. de méd., Paris, 121: 657-660. --r^ r (1940). Vaccination mixte contre l a f i e v r e jaune et l a variole sur des populations indigènes rtn q^nétral B u l l . Acad. nat. nÉd., 123: 137-147. s nés au ùenegai. SMITH, H.H. (1951) "Controlling yellow fever" Chap. 9, p. 619. McGraw-Hill Book C o . , Inc. SMITHBURN, K.C. (1951) "Immunology" Textbook on yellow fever.
8.
9. 10.
i b i d . Chap. 4, p.215.