Bull. Org. mond. Sante' 1964, 30, 783-794 Bull. Wid Hlth Org. f

Response of Volta Children to Jet of Combined Live Measles, and Yellow Fever

HARRY M. MEYER JR,' DANIEL D. HOSTETLER JR,1 BARBARA C. BERNHEIM,1 NANCY G. ROGERS,1 PAUL LAMBIN,2 ALBERT CHASSARY,2 REN, LABUSQUItRE 2 & JOSEPH E. SMADEL 1, 3

An earlier study established that Upper Volta children respond to with the Enders live attenuated measles strain in the same generalfashion as do children in the USA. The present report describes a second pilot project carried out in Ouagadougou, Upper Volta. During this investigation various mixtures oflive measles, smallpox and 17D yellow fever vaccines were introduced into susceptible infants by jet injection. Combining the attenuated virus vaccines did not alter or accentuate the characteristic clinical reactions elicited by the individual components, nor was there evidence of significant immunological interference. From this experience it is concluded that combined vaccination with these agents may be safely and effectively employed in larger programmes as the need dictates.

Recent experience in the Republic of Upper Volta inoculation. Subsequent work by others established in the use of Enders live attenuated measles that prepared in chick embryo and has been reported in another paper.' The results 17D could also be successfully indicated that the clinical and immunological administered to American adults by jet injection.5 responses of Upper Volta children to the vaccine On the basis of this experience our group recently were comparable with those observed in children in conducted a preliminary investigation in which other countries. Therefore, health personnel in the 24 American infants were vaccinated simultaneously area have chosen to consider practical means by with live measles and smallpox vaccines. The which measles might be carried out results (unpublished) indicate this to be a safe and within the framework of existing preventive effective immunizing procedure. The potential value programmes. of administering combined vaccines in field pro- Combined vaccines have been in general use for grammes is obvious, and the Minister of Health of many years and the advantages accruing therefrom Upper Volta wished to undertake a pilot study to are well known (Boue, 1960; Ramon, 1939). For the evaluate this procedure. most part, these combinations have consisted of The present report is concerned with a study of bacterial vaccines or , but in West Africa the efficacy and safety of various combinations of much has been done with a combination of two live, measles, smallpox and yellow fever vaccines admi- attenuated viral vaccines-those for yellow fever and nistered by jet injection to Upper Volta children, smallpox (Peltier, 1947). the majority of whom were less than one year of age Elisberg et al. (1956) showed that the cutaneous and susceptible to by all three viruses. and serological responses to jet injection of smallpox were to those observed following vaccine equivalent METHODS AND MATERIAL use of the conventional methods of percutaneous Altogether 545 children of Ouagadougou parti- 1 Division of Biologics Standards, National Institutes of Health, Bethesda, Md., USA. cipated in the study; none had a history of previous 2 Ministere de la Sante publique et de la Population, Ouagadougou, Upper Volta. 5 Binn, L. N. (1956) Quarterly progress report, January- 3 Deceased. March, Walter Reed Army Institute of Research, Washington, ' See the article by Meyer et al. on page 769 of this issue. D.C. (unpublished).

1436 - 783 784 H. M. MEYER JR AND OTHERS

FIG. 1 125 AGE DISTRIBUTION OF CHILDREN IN STUDY

100

o75 u-

0

I 50

25

5&6 7&8 9&10 11 &12 13-18 19-24 25;36 37-54 AGE (MONTHS) measles or of smallpox or yellow fever immuniza- Personnel tion. Children were placed in five groups of approxi- Vaccination and surveillance were performed at a mately equal size and received vaccines singly or centrally located dispensary by a team from the in combination as follows: (1) measles; (2) smallpox;' Division of Biologics Standards, National Institutes (3) yellow fever;' (4) measles and smallpox; and of Health (NIH), Bethesda, Md., USA, with the (5) measles, smallpox and yellow fever. Assignments assistance of nurses of the Ministry of Health, Upper to the vaccine groups were made sequentially as Volta. Administrative co-ordination of the project the children registered for vaccination, consideration was provided through the Ministry of Health. The being given only to equalizing the ages of vaccinees present study was also planned to serve as training in the groups. Although nutritional deficiencies and experience for the sixteen Volta nurses who were infectious and parasitic diseases are unusually to participate in a forthcoming mass measles vaccina- common in Volta children,2 none of those who tion campaign. With this in view, the Volta nurses presented themselves for vaccination were excluded performed all the operations associated with vaccina- from the study because of intercurrent diseases. tion, including surveillance of children, under the Before vaccination each child was given a physical immediate supervision of the NIH team. examination and a specimen of blood was obtained for future serological study. All groups were Surveillance vaccinated during a single week (1-6 October Parents were instructed to return with their 1962). children to the dispensary for observation every The age distribution of the children in the com- other day for three weeks following vaccination, or bined vaccine study is indicated in Fig. 1. daily if the child were ill. On arriving, a Volta nurse gave each child a preliminary examination which 1 Children who did not receive were revaccinated at the completion of the surveillance period. included the recording of temperature and determi- ' See the article by Meyer et al. on page 769 of this issue. nation of the presence or absence of rash and JET INOCULATION OF LIVE MEASLES, SMALLPOX AND YELLOW FEVER VACCINES 785 cutaneous smallpox reaction. Children with fever Preparation of vaccines for jet injection or other symptoms of illness were examined and Each of the three lyophilized vaccines was pack- treated by the NIH team. All medical records, aged in multiple-dose containers. Vials contained including those noting the type of vaccine admi- the following number of human doses: measles nistered, were available to persons conducting the vaccine, 25; smallpox vaccine, 100 (on the basis of surveillance examinations. percutaneous inoculation); and yellow fever vaccine, Vaccines 20. Immediately before use, measles vaccine was The following vaccines were employed in the rehydrated with 12.5 ml of sterile distilled water and study: (1) Enders B-level live attenuated measles yellow fever vaccine with 10.0 ml of sterile isotonic vaccine (Enders et al., 1960) grown in chick- saline. Smallpox vaccine was rehydrated with 1 ml embryo tissue cultures (this vaccine was supplied of sterile water but further dilution with gratis by Dr M. R. Hilleman, Merck Institute for solution was omitted. This rehydrated stock of Therapeutic Research, West Point, Pa., USA); smallpox vaccine was kept refrigerated for as long as (2) a commercial lot of licensed chick-embryo-type one working day and then discarded. Immediately bacteriologically sterile smallpox vaccine (Lederle before use the smallpox stock material was diluted Laboratories, Pearl River, N.Y., USA; Lot 2096- 1 :100 with sterile isotonic saline. Final vaccines 12A); and (3) a commercial lot of 17D yellow fever were used promptly; any remnants were discarded vaccine (National Drug Co., Philadelphia, Pa., within an hour. USA; lot 5312). All three vaccines were supplied Combined vaccines were prepared as follows. For in the lyophilized state and were maintained under the measles-smallpox mixture, rehydrated measles refrigeration. vaccine was used as the diluent to prepare the 1: 100 dilution of rehydrated stock smallpox vaccine. For Jet injection of vaccines the measles-smallpox-yellow-fever combination, In the current study the Automatic Hypodermic 10 ml of rehydrated measles vaccine were used to Jet Injection Apparatus of the Scientific Equipment rehydrate one vial of yellow fever vaccine. To this Manufacturing Corporation, New York, was em- 10-ml volume of bivalent mixture was added 0.1 ml ployed. For this project the jet nozzle of the appa- of the stock rehydrated smallpox vaccine. Thus, the ratus was modified in a simple manner to increase bivalent and trivalent mixtures contained the same the amount of vaccine deposited intradermally, an quantities of attenuated measles, smallpox and yellow important factor for immunization with smallpox fever vaccines as were contained in an equivalent vaccine (Elisberg et al., 1956). The modification volume of the respective monovalent preparations. consisted in the addition of a short sleeve cut from Each child, regardless of age, was jet-inoculated with stiff plastic tubing (wall diameter, 3 mm) which a 0.5-ml volume of the appropriate vaccine. The slipped over the nozzle and extended 4 mm beyond calculated amounts of the attenuated viruses ad- the jet orifice. The modified jet injector was held ministered to each recipient under these conditions against the arm in the usual manner with a pressure were: measles, 12 000 median tissue culture infec- of about five pounds. With the sleeve attached, tious doses (TCID50); smallpox, 1 500 000 TCID60; the jet orifice made only light contact against the and yellow fever, 6 300 000 median mouse lethal skin. doses (LD5O). In practice, groups of 20-40 children were assem- bled. Their left upper arms were cleansed with a Serum collection solution of surgical soap (Phisohex, diluted 1: 4 Blood specimens were collected from all children with boiled water) and the surface was wiped dry before vaccination, and from the majority a second with surgical gauze. The vaccine was prepared for sample was obtained three weeks after vaccination. use at this time, and 0.5-ml amounts were injected Sera were promptly separated aseptically from the into the deltoid region. clots, then stored and shipped in the frozen state to Those parts of the jet injector with which the the NIH for detailed examination. biological materials were in contact were washed and then sterilized in a pressure-cooker prior to each Antibody determinations vaccination period, i.e., twice a day. When not in Haemagglutination-inhibition (HAI) techniques use, the bottle of vaccine was removed from the were employed for the determination of antibodies vaccination gun and refrigerated. for measles and smallpox (Elisberg et al., 1956; 786 H. M. MEYER JR AND OTHERS

TABLE 1 PREVACCINATION SUSCEPTIBILITY OF CHILDREN IN STUDY TO MEASLES, SMALLPOX AND YELLOW FEVER

Prevaccination serological results Vaccination group Measles Smallpox Yellow fever No. neg./ % No. neg./ % No. neg./ % No. tested neg. No. tested neg. No. tested neg.

Measles 1181124 95 - | -_ Smallpox - - 88/101 87 - - Yellow fever - - - - 94/102 92 Measles-smallpox 109/117 93 105/117 90 - - Measles-smallpox-yellow- fever 91/101 90 92/101 91 93/101 92

Total 318/342 93 285/319 89 187/203 92

Rosen, 1961). Smallpox HAI tests were begun at an Previous : both sera neutralizing 25 or initial serum dilution of 1: 10, and those for measles more LD50 of virus with less than a 10-fold difference at 1: 8. When both specimens of paired sera were between the two. negative for measles antibodies they were retested at After completing analysis of the yellow fever data an initial dilution of 1: 2. Seroconversion was con- as described above, the raw data were re-examined sidered to have occurred if the prevaccination serum on the basis of the survival time of mice. By this of a child contained no demonstrable measles or method seroconversion was demonstrated in all the smallpox antibodies while the post-vaccination paired samples that had previously been interpreted serum gave positive results. as positive, as well as in most of those that had The mouse neutralization test was used for detec- formerly been considered equivocal and a few of tion of yellow fever neutralizing antibodies. In- those previously classified as negative. oculated mice were observed for 18 days; results The criteria used for defining seroconversion or no were calculated by several methods including the conversion by the survival time method were as conventional LD50 test (Lennette, 1959) and a follows. variation of the survival time method (Smith & Seroconversion: average survival time of mice Westgarth, 1957). inoculated with post-vaccination-serum and virus When the results of the yellow fever neutralization mixture at least eight days longer than mice receiving tests were calculated on the basis of a lethal end- prevaccination-serum and virus mixture. point, the following criteria were employed. No conversion: serum pairs giving less than eight Seroconversion: prevaccination serum neutraliz- days difference in average survival time. ing less than 25 LD50 of virus but post-vaccination serum neutralizing 25 or more LD50 and at least RESULTS 10-fold more than the prevaccination specimen. Prevaccination status of children in study group No conversion: neither serum capable of neutraliz- Clinical observation of the vaccinees indicated ing 25 or more LD50 of virus. that their health status was similar to that of children Equivocal: (a) Prevaccination serum neutralizing examined the previous year.1 Although members of 25 or more LD50 of virus but post-vaccination serum the present study were selected on the basis of no neutralizing 10-fold more than the prevaccination history of measles infection or vaccination against serum; or (b) prevaccination serum neutralizing less smallpox or yellow fever, serological studies revealed than 25 LD50 of virus and post-vaccination serum that some of the children had evidence of previous neutralizing 25 LD5i0 or more but with less than a 10-fold difference between the two. 1 See the article by Meyer et al. on page 769 of this issue. JET INOCULATION OF LIVE MEASLES, SMALLPOX AND YELLOW FEVER VACCINES 787

TABLE 2 SEROCONVERSION OF SUSCEPTIBLE CHILDREN AFTER ADMINISTRATION OF VACCINES SINGLY OR IN COMBINATION Children developing antibody against: Type of vaccine Measles a Smallpox Yellow fever b No. pos.l % No. pos.1 % No. pos.l % No. tested pos. No. tested pos. No. tested pos.

Measles 65/67 97 - - _ Smallpox - - 67/67 100 - - Yellow fever - - - - 70/72 97 Measles-smallpox 56/56 100 89/90 99 - - Measles-smallpox-yellow- fever 61/62 98 80/80 100 69/81 85

Total [ 182/185 | 98.4 { 236/237 [ 99.6 139/153 90.8

a Measles seroconversion calculated on children 8 months of age or older. b Yellow fever seroconversion calculated by survival-time method. experience with one or another of the viruses measles, smallpox and yellow fever vaccine given under discussion, as shown in Table 1. singly or in combination is summarized in Table 2. The occurrence of immunity to measles in about Not included in Table 2 are children from whom 7% of these children who were without a history of paired sera were not available, those with antecedent the disease is similar to our earlier experience.' A immunity, and finally, children under eight months of number of those with precedent antibodies against age who received measles vaccine. Thus, the numbers smallpox were re-examined for evidence of smallpox of children in the different groups in Table 2 varied vaccination scars, and their mothers were again from 56 to 90 as compared with the 101 to 124 per- questioned about prior vaccination. In the majority sons originally included in each group (Table 1). of these instances it was evident that the child had It is apparent from Table 2 that practically all the previously been vaccinated against smallpox. Some members of the three groups who received measles 8% of the children were designated as having had pre- vaccine developed measles antibody. The conver- existing antibodies against yellow fever; the inter- sion rate varied from 97% to 100%. Similarly, the pretation of these positive results is difficult. Yellow susceptible children who received smallpox inocula- fever vaccination had not been practised in Ouaga- tions showed evidence of seroconversion in almost dougou in children of this age for several years. 100% of instances. Finally, most of the children Furthermore, the disease had not been recognized who received yellow fever vaccine developed signi- in the area during the lifetime ofthese young Voltans. ficant levels of antibodies against yellow fever virus. It is possible that in some of the younger children The distribution of post-immunization measles the yellow fever antibody detected was the remnant antibody titres is summarized in Fig. 2. Results are of transplacentally transferred antibody from vac- plotted only for children who converted from nega- cinated mothers. This explanation does not suffice, tive to positive. It is apparent that the antibody however, in the older children. Some of the positive responses displayed by members of the three groups results attributed to yellow fever might have been were essentially the same. Furthermore, the geo- the result ofinfections with other members of Casals' metric mean titres did not vary appreciably. Group B arthropod-borne viruses (Casals, 1957). Measles vaccination in early infancy presents a Seroconversion ofsusceptible children special problem. An appraisal of the efficacy of measles immunization in very young children can be Pertinent information on the seroconversion of made in Table 3. Here, seroconversion data are susceptible children following inoculation with live presented for vaccinees 5, 6, 7 and 8 months 1 See the article by Meyer et al. on page 769 of this issue. of age compared with those 9 months and over. 788 H. M. MEYER JR AND OTHERS

FIG. 2 MEASLES ANTIBODY RESPONSE OF VACCINATED CHILDREN

30 No. Geom. Mean Sera Titre MEASLES ALONE 83 143 25 ---- MEASLES--SMALLPOX 84 152 - MEASLES-SMALLPOX- 74 182 YELLOW FEVER

.< zu w I LL I L

L.) w a- 1 0

5

0 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16284 MEASLES HAI ANTIBODY TITRE

WHO H814

TABLE 3 RELATION OF AGE TO MEASLES SEROCONVERSION a AFTER JET INJECTION OF LIVE MEASLES VACCINE

Type ofvaccine_ Age (months)b __ 5 6 7 8 | 9and over [ Measles alone 1/3 9/11 8/10 11/12 54/56 Measles-smallpox 1/2 12/17 15/15 16/16 40/40 Measles-smallpox-yellow-fever 1/1 8/10 415 10/10 51/52

Total 3/6 29/38 27/30 37/38 145/148

% seroconversion | 50 ] 76 90 97 98

a Expressed as number of serum pairs evidencing seroconversion over number of serum pairs tested. b Prevaccination sera of children negative at a 1:8 dilution for measles HAI antibody. JET INOCULATION OF LIVE MEASLES, SMALLPOX AND YELLOW FEVER VACCINES 789

FIG. 3 SMALLPOX ANTIBODY RESPONSE OF VACCINATED CHILDREN No. Geom. Mean 3S Sera Titre Smallpox alone 67 378 Measles-Smallpox 89 246

- 30 ...... Measles-Smallpox- 80 134 Yellow fever

25~-.

u- 20 * */.. z N U 15/

Y~~~1 / 10 /

I0 10 20 40 80 160 320 640 1 280 2560 >2560 HAI ANTIBODY TITRE

It is clear that in children less than eight or nine The antibody levels elicited by smallpox vaccine months of age there are many more vaccine failures, are summarized in Fig. 3. Here again, it is evident these increasing as the age decreases. This phe- that the distribution of antibody levels is about the nomenon of the relative resistance of younger same. However, high antibody titres occurred most children both to live measles virus vaccination frequently in the group receiving monovalent and to natural measles is well known and appa- vaccine and the titres in the bivalent group were rently related to the presence of minimal amounts generally higher than those in the trivalent group. of transplacentally transferred passive antibody Using an analysis-of-variance test, these differences (Reilly et al, 1961). Indeed, when the prevaccina- among the three preparations were found to be tion sera of these apparent vaccine failures were significant at the level P > 0.005.1 re-examined at lower starting dilutions-i.e., 1: 2 It may be noted that, although mixing of the and 1: 4-seven of those from children eight vaccines resulted in up to a threefold reduction in months of age or younger were found to contain the smallpox antibody response, no effect on the measles antibodies. Apparently, still others had antibody below the level detectable by present 1 All statistical analyses were performed by Dr Clifford J. Maloney and Mrs Dorothy F. Berg, Biometrics Section, serological techniques yet capable of rendering the Division of Biologics Standards, National Institutes of vaccine ineffective. Health, Bethesda, Md., USA. 790 H. M. MEYER JR AND OTHERS

FIG. 4 occurred subsequent to vaccination. These findings, SEROLOGICAL RESPONSE OF CHILDREN WITH PRE- which are in accord with the observations of Elisberg EXISTING SMALLPOX ANTIBODY TO JET INJECTION OF SMALLPOX VACCINE ALONE OR IN COMBINATION et al. (1956) in studies involving previously vaccin- WITH MEASLES OR MEASLES PLUS YELLOW FEVER ated adults, indicate that even partially immune VACCINES individuals may respond immunologically to jet injection of vaccine. 1280 r- 0 As described earlier, yellow fever seroconversion was calculated by two methods: LD50 and survival 640 -0 time. In Table 2, summarizing the serological responses of all vaccinated groups, the yellow fever data included were those obtained the survival 320 - A A 0 0 by time method. Table 4 presents the results obtained by both methods. The apparent differences in yellow 160 6 AA A 0 fever seroconversion between the monovalent and trivalent vaccine groups, as shown by each method s0 l 0 *A o /Type of calculation, are of borderline statistical signifi- Smolipox alone 0 cance. These observations suggest that the presence A Meosles-SmollpoK 0 40 / A Mesles-SmollpoxI A of the other two attenuated viruses may interfere / Yellow fever somewhat with the expected immunological expres- 20 sion of yellow fever vaccine.

I/ Clinical response to vaccination 10 20 40 80 160 320 640 1 280 PREVACCINATION SERUM VACCINIA HAI ANTIBODY TITRE No unusual or excessively severe reaction to vaccination occurred in any child. Measles and smallpox vaccination elicited the expected febrile incidence of primary cutaneous vaccinal reactions and cutaneous responses, while 17D yellow fever or rate of seroconversion could be shown. immunization produced no clearly discernible Nineteen children in the study had pre-existing clinical reaction other than an occasional febrile smallpox antibodies; their serological responses are episode. Fig. 5 shows the average daily temperature shown in Fig. 4. In 11 of these 19 instances a signifi- for all the children in the study during the 21-day cant (fourfold or greater) increase in antibody surveillance period. The data in this figure are of

TABLE 4 SEROCONVERSION FOLLOWING YELLOW FEVER VACCINE GIVEN ALONE OR WITH SMALLPOX AND MEASLES VACCINES

Seroconversion

ofMcalculathod a Group of vaccinees Positive Equivocal Negative No. % No. % No. %

Yellow fever 72 47 65 20 28 5 7 LD5o Yellow-fever- measles-smallpox 81 51 63 15 19 15 19

Yellow fever 72 70 97 - 2 3 Survival time Yellow-fever- measles-smallpox 81 69 85 12 14

a See text for details regarding methods of calculation of seroconversion. With the LDro method, three groups were designated; with the survival time method only two groups were designated- positive or negative. JET INOCULATION OF LIVE MEASLES, SMALLPOX AND YELLOW FEVER VACCINES 791

FIG. 5 AVERAGE DAILY POST-VACCINATION TEMPERATURES

38.0 A Measles a Measles-Smallpox 37.9 /, * Measles-Smallpox- Yellow fever 37.8 A Sma pox 37.7 ~~~~~~~~~~~~~~0Yellow Fever 37.6

37.5- M' 37.4

37.2 W~~~ ~ ~~~~~DYAFEAVCINTO 37.1 37 II I 0 2+3 4+5 6I~7 8+9 10+11 12+13 14+15 16+17 18+19 20+21 DAYS AFTER VACCINATION

Wtso '817 value primarily in delineating the periods during figure, children receiving measles vaccine developed which the individual vaccines can be expected to fever more frequently than those inoculated with elicit fever in recipients. Fevers associated with either smallpox or yellow fever vaccines singly. measles vaccination were first detected on the sixth However, in each of the two latter groups, 34 % of and seventh post-inoculation days. The height of vaccinees developed a temperature of 38°C or more these responses was greatest on the eighth and on at least one occasion. Fevers of 39°C or more ninth days, and they generally terminated before were equally common (20.0 %-22.8 %) among groups day 12. Smallpox vaccination was commonly receiving measles vaccine but considerably less associated with fever occurring four to seven days common (11.1 %-12.3 %) in groups not vaccinated after inoculation. Recipients of 17D yellow fever against measles. Among children vaccinated against vaccine exhibited no characteristic period of tem- yellow fever alone only nine individuals (12.3%) perature elevation. The two groups jet-inoculated experienced fevers of 39°C or more; all were less with combined vaccines tended to have an onset of than one year of age. It was interesting to note that fever by the fourth and fifth days, reflecting the with the other vaccines fevers were not similarly inclusion of smallpox vaccine in the mixture which restricted to the very young. High fevers, i.e., they received. These children experienced maximum 40°C or more, were rare irrespective of the vaccine temperatures on days 8 or 9 with termination of administered, ranging from 1 % to 5.9% in the five fever by day 12, as was observed in the group groups. It should be borne in mind that the definitive receiving measles vaccine alone. The peaks of the association of fevers with one or another type of febrile responses on days 8 and 9 were comparable vaccine poses certain problems since, in our pre- in all three groups receiving measles vaccine. ceding study,1 we found that about one-fourth of In Fig. 6 data pertaining to febrile reactions are the Voltans in a control group (given gamma- assembled to indicate the percentage of children in globulin alone) developed fever of 38°C or greater each group experiencing a maximum temperature during a two-week surveillance period. within certain defined ranges. As indicated in the 1 See the article by Meyer et al. on page 769 of this issue. 792 H. M. MEYER JR AND OTHERS

FIG. 6 MAXIMUM TEMPERATURES DURING 21-DAY POST-VACCINATION PERIOD

I.0O- 100 I- W2.S% 90 1-

80 I- ;~~~~... 4.1z 40.0.40.90 C 70 h 39.0 - 39.9 ° C U,w 60 1 38.0--38.9 ° C :4 I-- D z U 37.9 C OR LESS w 50 - (Z. w 0. 40 - 30 20

10

Measles Measles. Moasles- Smollpox Yellow Smallpox Yellow Fever Fever - Smallpox wHo 16

A maculopapular rash was detected between vaccine groups and bore no apparent relation to the the ninth and fifteenth post-vaccination days in type of vaccine administered. about 50% of children in each group who received Central nervous system involvement has been measles vaccine (measles alone, 45 %; measles- reported as an occasional grave complication of smallpox, 50%; and measles-smallpox-yellow-fever, both smallpox (Stuart, 1947) and yellow fever 52%). These rashes assumed a generalized dis- (Macnamara, 1953) vaccination and of natural tribution in about half the children involved and measles (Litvak et al., 1943). It is noteworthy, were only rarely of sufficient severity to mimic the therefore, that no child in the present study ex- cutaneous manifestations of natural measles. perienced any illness suggestive of . Smallpox vaccination was followed by the development of the typical primary cutaneous vaccinal reaction in 99 % of susceptible Voltans. DISCUSSION The character of the skin lesion was unaltered by the addition of measles or measles and yellow fever The data presented here indicate that live measles, viruses to the vaccine. smallpox and 17D yellow fever vaccines, singly or During the course of surveillance many children in combination, can be administered safely and manifested symptoms or signs of one or another effectively by jet inoculation into susceptible infectious or parasitic disease. Common complaints children. There was no indication that any of these were of diarrhoea, respiratory illness, otitis, purulent combinations potentiated the characteristic clinical conjunctivitis and skin infection. These problems reactions elicited by the individual attenuated were about equally distributed through the five viruses. Also, there was little evidence that viral JET INOCULATION OF LIVE MEASLES, SMALLPOX AND YELLOW FEVER VACCINES 793 interference substantially diminished the immuno- i.e., vaccines suspended in glycerol or gum arabic, logical response to the combined vaccines. Measles are poorly handled in jet guns. and smallpox seroconversions were uniformly Those seeking to carry out preventive medicine excellent, occurring in 97%-100% of all groups programmes in West Africa are beset by many receiving these vaccines. The smallpox HAI anti- problems. The population is widely dispersed, body response tended to be slightly lower in Voltans residing for the most part in rural areas which are receiving the mixtures. However, the geometric often difficult to reach and soAmetimes inaccessible mean antibody titres of each of the three groups during portions of the rainy season. Moreover, receiving smallpox were of a high order funds and personnel available for health work are and comparable to those observed by others in frequently limited. Nevertheless, Upper Volta and persons responding to primary vaccination with her neighbours are plagued by a number of major either the calf-lymph or the chick-embryo type of endemic diseases (Senecal et al., 1962). Two of vaccine (Elisberg et al., 1956; McCarthy & Downie, these, smallpox and yellow fever, are controlled by 1958). mass vaccination (Peltier, 1947). Measles, another Only a few children evidenced antecedent immunity of these endemic threats, has been described as one at the time of smallpox vaccination; these frequently of the greatest hazards to child health in West experienced an increase in antibody subsequent to Africa today (Armengaud & Frament, 1960; vaccination (Fig. 4). Theoretically, jet-inoculated Morley et al., 1963; Senecal et al., 1962). The Enders vaccine might be more immunogenic than similar live attenuated measles vaccine, by conferring long- material administered in the traditional manner, term immunity to recipients following a single since an antigenic mass has been introduced which inoculation, offers a practical solution to this grave might stimulate antibody formation, even in the problem. As the West African infant emerges from absence of virus multiplication. Yellow fever sero- the shelter of maternal antibodies, he enters a period conversion was observed more frequently in the of high risk to measles. To counter this hazard, group that received only yellow fever vaccine, but protective immunization should be instituted at the the over-all conversion rate of 90.8 % for groups earliest practical age. Live measles vaccine can be given 17D virus was considered satisfactory and in given with full effectiveness by the eighth or ninth keeping with the general experience in the use of month of life and may, if indicated, be employed 17D-type vaccine (Stuart, 1956). with a predictable reduction of efficiency in younger Regarding the use of jet injectors, several general children (see Table 3). comments are in order. These devices operate on Looking to the future, one hopes it will be pos- the principle that vaccine, when forced through a sible to extend the current anti-smallpox and anti- minute orifice under high pressure, emerges as a yellow fever programmes to include measles immun- high-speed jet capable of penetrating the skin ization. This could be most simply accomplished (Hingson et al., 1963; Warren et al., 1955). The if existing mobile health teams could simultaneously character of penetration is dependent upon several vaccinate against measles as well as smallpox and factors such as orifice diameter, pressure and yellow fever. Unfortunately, live measles vaccine proximity of the orifice to the skin surface. As shows little activity by the traditional inoculation described earlier, slight modifications may be made route (Kempe et al., 1960; and unpublished observa- to increase the intradermal inoculum; however, tions of the present authors), which is widely used even with such changes, significant amounts of in West Africa for both smallpox and yellow fever vaccine are deposited in the subcutaneous and intra- inoculation. Measles vaccination with syringe and muscular layers. These comments have been made needle would pose several technical and financial to call attention to two practical considerations. problems for large field programmes. Many of Because of the depth of penetration, material selected these difficulties could be overcome by the use of for jet injection should be bacteriologically sterile jet injectors which, as demonstrated in this study, or at least pathogen-free. Furthermore, the dynamics can be successfully employed to deliver any of these of mechanical operation are such that viscous fluids, three vaccines, either alone or in combination. ACKNOWLEDGEMENTS The authors wish to thank Mrs Ethel D. Rosenblatt, Mr Raymond L. Vaughn and 'Mr Rudyard S. Wallace for technical assistance. 794 H. M. MEYER JR AND OTHERS

RtSUMt

Une premiere etude de vaccination contre la rougeole, echantillons de serums couples ont Wt6 pr6leves avant et effectuee en Haute-Volta, avait montre que la reponse apres vaccination. Cette derniere a ete effectu6e par clinique et immunologique des enfants de ce pays etait injections sous pression sans aiguille. semblable a celle des enfants d'autres continents. Les Les r6actions consecutives a la vaccination (fievre, autorites sanitaires de Haute-Volta ont alors decide rash) se sont manifestees comme on I'attendait. L'asso- d'entreprendre une nouvelle etude, comportant une ciation de virus attenues semble n'avoir ni modifi6 ni vaccination mixte, ajoutant la rougeole au vaccin associe' potentialise les r6actions cliniques, provoqu6es par chacun deja en usage contre la variole et la fievre jaune, afin de des virus composant le melange. proteger les nourrissons contre cette maladie qui est Le virage serologique a ete observ6 chez 97-100% des l'une des plus graves de l'enfance, dans le cadre du enfants vaccines contre la rougeole, chez 99-100% des programme de medecine preventive. vaccines contre la variole, et 87-90% des vaccines contre Un total de 545 enfants, la plupart de moins d'un an, la fievre jaune. Aucune interference immunologique et tous seronegatifs, ont ete repartis en cinq groupes, qui appreciable n'a e not6e chez les enfants ayant requ les ont requ respectivement: du vaccin anti-rougeole; du vaccins mixtes. vaccin antivariolique; du vaccin antiamaril; un vaccin Les auteurs concluent que le vaccin mixte (variole- mixte variole-rougeole; un vaccin mixte variole-fievre fievre jaune-rougeole) peut etre administr6, selon la jaune-rougeole. Tous les enfants ont ete examines avant technique particuliere indiquee, avec efficacite et s6curite. vaccination et suivis pendant trois semaines apres. Des

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