Vaccination of Children With Human Cell Culture Rabies Vaccine

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PEDIATRICS Vol. 63 No. 2 February 1979 219

Vaccination

of Children

With Human

Cell Culture

Rabies

Vaccine

Stanley A. Plotkin, M.D., and Tadeusz Wiktor, D.V.M.

From the Unit-ersity of Pennsylvania, the Wistar Institute of Anatomy and Biology, and the Dicision of

Infectious Diseases, Children ‘s Hospital of Philadelphia, Philadelphia

ABSTRACT. Three children exposed to the bites of proved

or probably rabid animals were immunized with human rabies immune globulin and human diploid cell culture vaccine. There were no significant clinical reactions, and all three developed high levels of rabies antibody. The patients have remained well from four to 18 months. Pediatrics 63:219-221, 1979, rabies vaccination, immunization, human

cell culture caccine.

The clinical trials of a new rabies vaccine developed at the Wistar Institute has evoked considerable interest. The new vaccine is prepared by concentrating and inactivating virus

harvested from human diploid cell cultures.”2

The preparation, called human diploid cell

vaccine (HDCV), is free of nonhuman proteins

but is rich in rabies antigen. As a consequence, its immunogenicity has been 10 to 20 times greater than that of duck embryo vaccine (DEV). More-over, serious reactions have been extremely

uncommon.’-4 Many reports have testified to the

high antibody responses of adult volunteers given HDCV.55 Two reports-’#{176} of successful protection in extensive postexposure studies have been published. However, these two studies both used French-made whole virus vaccine, and neither

specifically described vaccination of children.

Our report describes the results of vaccination of three children who had been exposed to proved or probable rabies with American-made split-product HDCV.

Health potency tests, the antigenic potency of the lots used was approximately three units.

Virus-neutralizing antibodies were measured

by rapid fluorescent focus inhibition’2-a test that

depends on the inhibition of fluorescent foci in

BHK-21 cell cultures. The results are converted to international units (IU) by comparison to standard antiserum tested in parallel. A level of 0.3 IU is

usually equivalent to a 1/16 dilution of serum;

anything less than 0.3 IU is considered to be negative for a specific antibody.

CASE REPORTS

Case 1

A 22-month-old girl was standing on a sidewalk in a rural

southeastern Pennsylvania town late one afternoon when a

bat swooped down and fastened its teeth to her right ankle.

Her father pulled the bat off, killed it, and took it to the Pennsylvania State Department of Health Laboratory. Rabies was confirmed in the bat brain by direct fluores-cence.

The following day the child was seen at Children’s Hospital of Philadelphia, where 20 lU/kg of human rabies immune globulin (HRIG) were administered, half locally in the right ankle and half in the right arm.

A five-dose regimen of HDCV was administered: 1 ml of vaccine was given intramuscularly on days 0, 3, 7, 14, and 30. No clinical reaction was observed by us or by the parents. Specifically, there was no significant local reaction and no

fever, malaise, or other general symptoms.

Results of antibody studies are given in the Table. At the

time of this writing, the child has survived for 17 months since the time of the bite.

Case 2

A boy aged 3 years 9 months was playing at a campsite in

West Virginia (near the Virginia border) when a fox jumped out of the underbrush and clamped its jaws on the child’s

MATERIALS AND METHODS

In the HDCV (prepared by Wyeth

Laborato-ries), virus was inactivated and disaggregated by

n-tributyl phosphate.” A dose consisted of 1 ml

given intramuscularly in the deltoid or quadriceps

muscle. According to National Institutes of

Received January 17; revision accepted for publication July

14, 1978.

ADDRESS FOR REPRINTS: (S.A.P.) Department of

Infec-tious Diseases, Children’s Hospital of Philadelphia, 34th

Street and Civic Center Boulevard, Philadelphia, PA

19104.

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220 RABIES VACCINE

ANTIBODY RESPONSE TO PosTr.xPosuiu RABIES VACCINATION OF CHILDREN WITH HUMAN DIPL0ID CELL VACCINE (HDCV)

Time After Vaccination

Patie nt 1 Patient 2 Patient 3

‘-

--

C

-Vaccine Antibody Vaccine Antibody Vaccine Antibody

Dose Tite4 Dose Titer Dose Titer

0 day#{176} V(+ 1day)t V(+ 3 days)t <0.4 V( + 5 days)t <0.3

3day V V

7 day V <0.1 V 0.6 V <0.3

14 day V 13.5 V 1.1 V 0.4

2lday V

28th>’ 17 V 27

3Oday V 20

38day 30

42day 90 30

3mo 35

4mo 22

7mo 7

18 mo 2.4

#{176}Counting day of first vaccination as day 0.

tNumber of days after bite on which HDCV was first administered.

Antibody titers by the rapid fluorescent focus inhibition test in international units.

right elbow. The boy’s father rushed up and struck the fox,

which caused it to run off. The child was treated at a hospital

in Virginia where local irrigation was performed and HRIG

was administered. Five doses of DEV were also given over a

three-day period.

Since the parents lived in the Philadelphia area, the boy

was referred to Children’s Hospital, where he was first seen

three days after the bite. HDCV was administered on a

four-dose schedule (days 0, 7, 14, and 21) with antibody response beginning by ten days after the bite (Table). No

clinical reactions of any type were seen. Thirty-one months

later the boy is still well.

Case 3

A 13-year-old native of suburban Philadelphia was on

vacation with his family in Cerrillos, New Mexico, when he sustained an unprovoked attack by a stray dog. The boy was

bitten on the left calf. Attempts to apprehend the dog were

unsuccessful. Five days after the bite the family returned to

Philadelphia, and HRIG (20 lU/kg) was administered by the

family physician.

On the same day the boy was referred to Children’s

Hospital where we began a regimen of five doses of HDCV

given at 0, 3, 7, 14, and 28 days. Although the patient had a

history ofallergic asthma, no reactions were noted except for

headache after the third injection. Antibody data are shown

in the Table. After 21 months the boy is still well.

DISCUSSION

Isolated case reports do not prove the efficacy of a vaccine; this can be established only by controlled trial. Obviously, with rabies no controlled trial is possible and only accumulated

experience compared with expected rabies

mci-dence can help judge protective effects. Rabies in the biting animals was definite in case 1, highly probable in case 2, and possible but not certain in case 3. The expected incidence of rabies in

untreated persons is 40% to 50%.”-’ Although

failures of nerve tissue vaccine or DEV have been

recorded,’ the protective efficacy of the former has been estimated as 80%,’ while no estimate has been made for the latter.

The success of French-made HDCV in West Germany9 and Iran,’#{176}where there were no fail-ures in approximately 90 cases, might lead one to estimate that HDCV is at least 97% effective (less than one case observed and 36 expected). In the United States, approximately 120 individuals with

proved rabies exposure have been treated

success-fully with American split-product vaccine (Marc

W.

Deitch, MD, personal communication,

Janu-ary 1979).

Although no firm conclusion with respect to the efficacy of HDCV may be drawn from the three cases reported here, two facts are remark-able: the absence of significant reaction to the vaccine and the high antibody titers developed

after only four or five doses of the vaccine.

In adult volunteers vaccinated with HDCV

before exposure, higher reaction rates have been

reported (sore arm, 70%; malaise, 15%; fever, 5%; allergic reaction, 0.i%).’ Since no placebos were used in these trials, we are unable to say that adults are truly more prone to reactions than children. Fortunately, the anaphylactic reactions that are frequently reported after DEV adminis-tration before or after exposure’8 have not been a feature of HDCV vaccination.

The peak antibody responses in our patients were to 30 IU or higher in each case. The correspondence between international unit and

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ARTICLES 221

titer will vary from laboratory to laboratory, but in general 1 IU equals a 1/40 dilution. It is

noteworthy that after a full course of DEV and

antiserum, vaccinees who respond usually will have peak levels lower than 2 lU.’

An official schedule for postexposure HDCV vaccination has not been determined. The

Germany and Iranian studies were conducted

with a regimen of single doses on days 0, 3, 7, 14, 30, and 90, whereas the U.S. Center for Disease

Control has used days 0, 7, 14, and 21 for

inoculation. In our opinion, the important

consid-eration is. to administer three intramuscular doses

during the first two weeks and a booster dose 21

to 30 days after vaccination is begun. Insufficient experience with intradermal administration of the American-made HDCV precludes recommenda-tion of this alternate route. As with other rabies

vaccines, HRIG should be administered at the

beginning to provide immediate antibody.2#{176} The serologic data provided above illustrate two points with regard to HRIG. First, although the doses of HRIG administered have been reported to provide immediate antibody,

anti-body in serum was not detected for about one

week. It is possible that the large antigenic mass

of the HDCV binds the passively administered

antibody and that a higher dosage of HRIG will

be necessary if passive antibody is to be used with a vaccine more potent than DEV. Additional

studies will be necessary to answer this question.

Second, previously published data’ on antibody

responses to HDCV administered without HRIG

given simultaneously showed high titers by day

14. In patients 2 and 3, the titers were low until

days 21 to 28, probably because of the dampening

effect of the HRIG. The ideal dose of HRIG when

used in combination with HDCV has not been

established yet.

The replacement of DEV by HDCV would remove most of the concerns of physicians about postexposure rabies immunization, ie, allergic reactions and failure to produce antibodies, and,

it is hoped, without encouraging indiscriminate

use. Licensure of this vaccine is presently under consideration by the Bureau of Biologics. It is available tinder certain conditions as an investiga-tional drug from the Center for Disease Control and from us for patients in the Philadelphia area.

REFERENCES

1. Wiktor TJ, Fernandes MV, Koprowski H: Cultivation of rabies virus in human diploid cell strain WI-38. I I7fllflUflOl 93:353, 1964.

2. Wiktor TJ, Plotkin SA, Crella DW: Human cell culture rabies vaccine. JAMA 224:1 170, 1973.

3. Plotkin SA, Wiktor TJ, Koprowski H, et al:

Immuniza-tion schedules for the new human diploid cell

vaccine against rabies. Am I Epidemiol 103:75,

1976.

4. Cabasso VJ, Dobkin MB, Roby RE, et al: Antibody

response to a human diploid cell rabies vaccine. Appl Microbiol 27:553, 1974.

5. Aoki FY, Tyrrell DAJ, Hill LE, et al: Immunogenicity

and acceptability of a human diploid-cell culture

rabies vaccine in volunteers. Lancet 1 :660, 1975.

6. Cox JH, Schneider LG: Prophylactic immunization of

humans against rabies by intradermal inoculation of

human diploid cell culture vaccine. I Clin Microbiol 3:96, 1976.

7. Turner GS, Aoki FY, Nicholson KG, et al: Human

diploid cell strain rabies vaccine: Rapid prophylac-tic immunisation of volunteers with small doses.

Lancet 1:1379, 1976.

8. Garner WR, Jones DO, Pratt, E: Problems associated with rabies preexposure prophylaxis. JAMA 235:1131, 1976.

9. Kuwert EK, Marcus I, Hoher PG: Neutralizing and complement-fixing antibody responses in pre- and

post-exposure vaccinees to a rabies vaccine

produced in human diploid cells. I Biol Stand 4:249,

1976.

10. Bahmanyar M, Fayaz A, Nour-Salehi 5, et al: Successful

protection of humans exposed to rabies infection: Postexposure treatment with the new human diploid cell rabies vaccine and antirabies serum.

JAMA 236:2751, 1976.

11. Tint H, Dobkin M, Rubin BA: A new tissue culture (WI-38) rabies vaccine, inactivated and disaggre-gated with tri-(n)-butyl phosphate, International Symposium on Rabies, Lyon, 1972. Symp Ser Immu-nobiol Stand 21:132, 1974.

12. Smith JS, Jager PA, Baer GM: A rapid tissue culture test

for determining rabies neutralizing antibody. WHO Monogr Ser 23:101, 1973.

13. Baltazard M, Bahmanyar M, Ghodssi M, et al: Essai pratique du serum antirabique les mordus par loups

enrages. Bull WHO 13:747, 1955.

14. Plotkin SA, Clark HF: Committee on immunization:

Prevention of rabies in man. I Infect Dis 123:227,

1971.

15. Hildreth EA: Prevention of rabies, or the decline of Sirius. Arch Intern Med 58:883, 1963.

16. Veerarghavan N: Scientific Report for 1968. Coonoor, Tamil Nadi,, Pasteur Institute of Southern India,

1969.

17. Plotkin SA, and Wiktor T: Rabies vaccination. Ann Rev Med 29:583, 1978.

18. Rubin RH, Hattwick MAW, Jones S. et al: Adverse

reactions to duck embryo rabies vaccine. Ann Intern Med 78:643, 1973.

19. Ellenbogen C, Slugg P: Rabies neutralizing antibody:

Inadequate response to equine antiserum and

duck-embryo vaccine. I Infect Dis 127:433, 1973.

20. Hattwick MAW, Rubin RH, Music 5, et al: Postexposure rabies prophylaxis with human rabies immune glob-ulin. JAMA 227:407, 1974.

ACKNOWLEDGMENTS

This work was supported in part by grant AI-09706 from

the National Institutes of Allergy and Infectious Diseases. We appreciate the help provided by Drs. E. Rosanoff and

H. Tint of Wyeth Laboratories for making vaccine available

to us.

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1979;63;219

Pediatrics

Stanley A. Plotkin and Tadeusz Wiktor