- Email: [email protected]
Antibody persistence, 32 years after post-exposure prophylaxis with human diploid cell rabies vaccine (HDCV)
Vaccine 29 (2011) 3742–3745
Contents lists available at ScienceDirect
Vaccine journal homepage: www.elsevier.com/locate/vaccine
Antibody persistence, 32 years after post-exposure prophylaxis with human diploid cell rabies vaccine (HDCV) Ahmad Fayaz ∗ , Susan Simani, Alireza Janani, Firouzeh Farahtaj, Peyvand Biglari, Nader Howeizi, Nasser Eslami WHO-Collaborating Center for Reference & Research on Rabies, Pasteur Institute of Iran, Tehran, Iran
a r t i c l e
i n f o
Article history: Received 5 January 2011 Received in revised form 7 March 2011 Accepted 16 March 2011 Available online 31 March 2011 Keywords: Rabies Post-exposure prophylaxis Antibody persistence
a b s t r a c t In 1975–1976 forty-five persons severely bitten by rabid wolves and dogs in Iran were treated successfully against rabies with HDCV. In this study contact was made with 26 of 45 above persons, 32 years after their initial treatment and all had rabies neutralizing antibody ranging from 0.3 to 2.69 IU/ml of serum. Of the 26 persons, 17 had received a booster dose of HDCV, 28 years ago and the remaining 9 persons, who had not received any booster since the initial treatment, were given one booster dose of HDCV. All 9 of these patients developed an anamnestic response after their booster inoculation. This study confirms the persistence of rabies neutralizing antibody in persons that received post-exposure vaccination with HDCV, 32 years previously. Furthermore, a single booster inoculation with HDCV resulted in anamnestic response in all individuals. © 2011 Elsevier Ltd. All rights reserved.
1. Introduction Rabies is an invariably fatal disease in humans and animals once clinical symptoms are evident. It is also a unique disease in that patients can be protected from developing clinical disease, even after exposure, through the administration of post-exposure prophylaxis (PEP). This remarkable fact was discovered by Louis Pasteur and Emil Roux in 1885 when they began to successfully save the lives of bitten patients by vaccinating them with increasingly virulent doses of spinal cord from infected rabbits. In the decade following Pasteur and Roux’s first treatment for exposed patients, rabies vaccines gradually improved but they were still produced in vivo by inoculating animals with live rabies virus and harvesting their infected brain material until the late twentieth century when for the first time, rabies vaccines were successfully produced in cell cultures. Human diploid cell rabies vaccine (HDCV) was the first globally successful cell culture rabies vaccine and must be credited for saving the lives of millions and perhaps even billions of lives since it was developed and first marketed in the 1970s. HDCV was an entirely new concept in the manufacture of rabies vaccine and as such its efficacy was unknown. The first experimental batch of the vaccine was produced and tested in animals and finally in human volunteers and was found to be
∗ Corresponding author at: No. 69, 12th Farvardin Ave., Pasteur Ave., Pasteur Square, Tehran 1316943551, Iran. Tel.: +98 21 66403496; fax: +98 21 66480777. E-mail address: [email protected] (A. Fayaz). 0264-410X/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.vaccine.2011.03.048
highly immunogenic; the Institut Merieux in Lyon, France, agreed then to produce large quantities of HDCV for clinical trials in Iran [1,2]. Convinced of the safety of the HDCV and promptness of the antigenic response in humans, and with the consent of Iranian responsible authorities, HDCV was used for the first time in Iran for PEP in human as follows: in 1975–1976, 45 persons that were severely bitten by rabid wolves and dogs received PEP in what was to become the backbone of the modern PEP regimen. All of these patients had received multiple wounds and were at risk of contracting rabies if not treated. The wounds were inflicted by six dogs and two wolves in rural areas of north western part of Iran between June 1975 and January 1976. All animals were confirmed to be rabid by immunofluorescent test of brain tissue and where possible, titration of the virus present in the salivary glands of the animals was conducted. All patients received the first dose of vaccine simultaneously or within one hour after being administered heterologous anti rabies serum. The complete course of HDCV treatment consisted of 5 doses inoculated subcutaneously on days 0, 3, 7, 14, 30 and a booster dose on day 90. At the end of 2007, after several trips to different rural areas in Iran, we were able to locate 26 of 45 patients that were exposed and initially received PEP, including the newly developed HDCV, 32 years ago. In this study, we report on the levels of rabies virus neutralizing antibody (RVNA) present in their blood and their response to one booster dose of HDCV.
A. Fayaz et al. / Vaccine 29 (2011) 3742–3745
3743
Table 1 Exposed patients groups according to the animal and location of the attack and the date of exposure. Group
Species
A B C D E
Dog Dog Dog Wolf Dog
F G
Dog Wolf
H
Dog
a b c
Village
Kharileh Seylab Cheverin Aghbulagh Baderlou Oghul Beyk Qara-Boulagh Alishtar Hossein-Abad Bagher-Abad Darrehchin Chakmikush Bouryabad
Date of attack
No. of persons bitten
June 9, 1975 July 19, 1975 September 12, 1975 October 20, 1975 October 26, 1975 October 26, 1975 October 27, 1975 October 31 1975 November 27, 1975 November 27, 1975 January 19, 1976 January 19, 1976 January 20, 1976
7 1 11 7 1 1 2 6 1 1 4
Rabies confirmationa Brainb
Salviac
+ + + + +
NA NA NA 5.6 NA
+ +
5.0 5.1
+
4.1
3
NA indicates not available; + indicates presence of rabies antigen. Presence of rabies antigen in brain tissue demonstrated by direct immunofluorescence. Rabies virus titers of salivary glands, given in median lethal dose for a mouse/0.03 ml (log 10).
2. Materials and methods
subjects who did not receive any booster dose since 32 years ago.
2.1. Historical backgrounds 2.4. Serology The protocol for a detailed field trial to assess the immunogenicity of the HDCV was established by an international scientific seminar held in Geneva in 1973, and WHO-Collaborating Centre for Reference & Research on Rabies in Tehran was entrusted with the clinical trials for the new HDCV [1]. The high level of specific antibody response of human volunteers vaccinated with one to five doses of HDCV, essentially without side effects, had been confirmed by Bahmanyar [3]. In 1975–1976, the event of 45 persons being bitten by rabid dogs and wolves occurred and provided an opportunity to use the newly developed HDCV in conjunction with heterologous anti-rabies serum for the first time in history a new regimen for PEP in patients exposed to known rabid animals. The 45 exposed patients were divided in to 8 groups according to Table 1. The number of wounds per persons varied from a single penetration wound to 25 multiple severe lacerations about the face and head. This treatment resulted in protection of all individuals against rabies [4]. In 1979, contact was established with 27 of 45 mentioned persons four years after their severe exposure to rabies virus and successful protection. During that time these persons maintained rabies neutralizing antibody at the level of 2–91 IU/ml of serum. A single booster inoculation of HDCV, resulted in the increase of neutralizing antibodies [5]. 2.2. Patients In 2007, we studied the data concerning 26 of the 45 mentioned group, of which, 17 belonged to the persons who received PEP (in 1975–1976) and one booster dose in 1979 and the rest (9 persons) had not received any booster up to 2007. So, for the latter 9 persons, the titer of rabies neutralizing antibody was determined before and after receiving a single dose of booster HDCV. According to the biting animals, the 26 exposed persons were belonged to the 5 groups A, C, D, F and H (Table 2). 2.3. Vaccine Human diploid cell rabies vaccine produced by Sanofi Pasteur, Lyon, France was used in the study. Its batch number was Z1037-1, prepared from supernatant of Human Embryonic Lung Fibroblast Culture W138, infected with the Pitman Moore strain of rabies virus. A single dose of HDCV was only administered to 9 of 26
Blood samples were obtained from 26 of 45 exposed persons who were treated 32 years ago. Of the 26 exposed individuals nine received one booster dose of HDCV and their blood samples were obtained ten days after the booster. In our lab, serum samples were separated, inactivated at 56 ◦ C and stored at −20 ◦ C until titration. Antibody persistence was evaluated by titration of neutralizing antibodies with Rapid Fluorescent Focus Inhibition Test (RFFIT) [6]. 3. Results Twenty-six of the 45 persons that had received PEP with heterologous anti-rabies sera and the “then” newly developed HDCV in the first clinical field trial conducted between1975 and 1976 were located. The original 45 subjects had been initially separated into 8 groups depending on the animals that initially inflicted the wounds (Table 1). The 26 persons that were contacted in 2007 were originally members of groups A, C, D, F and H as follows (Table 2): (1) 3 people from group A, wounded by a laboratory-confirmed rabid dog in June 1975. (2) 7 persons from group C with deep wounds, bitten by a laboratory-confirmed rabid dog in September 1975. (3) 6 persons from group D with wounds in their heads and faces, bitten by a laboratory-confirmed rabid wolf in October 1975. The viral titer in the salivary glands of this wolf had been 105.6. (4) 5 people from group F wounded by a laboratory-confirmed rabid dog with salivary glands viral titer of 105 in November 1975. (5) 5 persons from group H bitten by a laboratory-confirmed rabid dog with salivary glands viral titer of 104.1 in January 1976. All of the 26 persons had RVNA levels ranging from 0.3 to 2.69 IU/ml, four of these patients had received two doses of Vero rabies vaccine after re-exposure in 2005. The RVNA titer of the 9 subjects who had received no rabies vaccine during the past 32 years ranged from between 0.3 and 0.98 IU/ml. Ten days after having received one booster of HDCV in 2007, the range of RVNA in these nine persons was between 2.6 and 20 IU/ml.
3744
A. Fayaz et al. / Vaccine 29 (2011) 3742–3745
Table 2 Age and sex of patients, biting animal and the date that received their initial PEP and the dates that patients received one additional dose of HDCV. Rabies virus neutralizing antibody titers are expressed in IU/ml of serum. Group
No.
Patient sex/age yra
Biting animal
Date of PEP
Antibody titers 32 years After PEP: IU/ml of serum 26 Individuals
9 of 26 individuals who received HDCV booster in 2007
A
1 2 3
M/18 F/20 M/11
Dog // //
June 1975 // //
0.5b 0.3b 0.3b
C
4 5 6 7 8 9 10
M/10 F/23 M/7 M/8 M/7 M/9 M/11
Dog // // // // // //
September 1975 // // // // // //
0.98 0.3 0.98 0.3b 0.3b 0.3b 1.0b
20 20 20
D
11 12 13 14 15 16
M/19 F/35 F/45 M/45 M/7 M/40
Wolf // // // // //
October 1975 // // // // //
0.3 0.91 0.75 0. 3 0.79 0.9
2.6 10.4 5.5 3.2 8.3 3.5
F
17 18 19 20 21
F/7 F/12 M/8 M/3 M/4
Dog // // // //
November 1975 // // // //
2.18c 2.69c 2.1c 0.55b 1.2c
H
22 23 24 25 26
M/15 M/15 M/16 M/12 M/16
Dog // // // //
January 1976 // // // //
0.31b 1.1b 0.95b 0.9b 1.0b
a b c
Yr age: at the time of exposure. Received HDCV booster in 1979. Received HDCV booster in 1979 and 2 doses of Vero Rabies Vaccine in 2005 after re-exposure.
The remaining 17 persons who had received one dose of HDCV vaccine 4 years after original treatment (28 years ago), had RVNA titers ranging between 1.2 to 2.69 IU/ml at the time of this study although, four of these subjects received two shots of Vero rabies vaccine 3-days, apart during 2005 after being exposed to suspect rabid animals. The RVNA titer of these four patients ranged between 1.2 and 2.69 IU/ml. 4. Discussion In 1980, we reported adequate RVNA titers in 27 patients that had received PEP with HDCV and Equine Rabies Immunoglobulin four years earlier and after a single booster inoculation of HDCV in 1980, resulted in a sharp increase in the level of RVNA [5]. In 1994, Traenhart reported the existence of humoral and cellular immunity as long as 14 years after original vaccination. All 18 subjects in Traenhart’s study had values ≥0.5 IU/ml measured by RFFIT [7]. Longevity of rabies neutralizing antibody after administration of HDCV was studied by Briggs et al. [8]. Suwansrinan et al. carried out a prospective study on 118 rabies vaccine recipients who had received pre- or post-exposure regiments with PVRV or HDCV, 5–21 years previously. Rabies neutralizing antibody was detectable in the sera of all the subjects [9]. This study examined the anamnestic response of the patients involved in the first field study using a modern cell culture rabies vaccine, HDCV, which would eventually replace the use of rabies vaccines made in the brain tissue of infected animals. The field study, conducted in 1975–1976 in patients from rural Iran, was the first time in history that patients exposed to confirmed rabid animals were treated with this new type of vaccine using a reduced PEP
regimen. Therefore, the data in this paper represent the most accurate information on the longevity of RVNA titers and the ability for a patient to evoke an anamnestic response after vaccination with HDCV. The data confirms the persistence of rabies neutralizing antibody for up to 32 years after vaccination with HDCV. Furthermore one booster dose of HDCV to 9 subjects who did not received any booster of rabies vaccine during 32 years, resulted in an increase in the level of RVNA proving that these patients were able to develop an anamnestic response. Due to the fact that other reports have demonstrated the equivalence of immunity for other WHO prequalified cell culture rabies vaccines. These results indicate that the persons who have previously received PEP even 32 years previously will develop an anamnestic response to a single booster dose of a cell culture rabies vaccine [10–11]. The level of antibody response after vaccination varies in different subjects, but the lowest titer correlated with protection recommended by WHO is 0.5 IU/ml [12] and in our group studied the titer level after booster injection was significantly higher. Acknowledgments We are very grateful to Dr. Deborah J. Briggs, executive director of the global Alliance for Rabies Control, for proof reading and contributing to the manuscript and Dr. Anis Jafari from Pasteur Institute of Iran for critical review of the manuscript. References [1] Sikes RK, Cleary WF, Koprowsky H, Wiktor TJ, Kaplan MM. Effective protection of monkeys against death from street virus by post-exposure administration of tissue culture rabies vaccine. Bull WHO 1971;45:1–11. [2] Wiktor TJ, Plotkin S, Grella DW. Human cell culture rabies vaccine: antibody response in man. JAMA 1973;224:1170–1.
A. Fayaz et al. / Vaccine 29 (2011) 3742–3745 [3] Bahmanyar M. Results of antibody profiles in man vaccinated with HDC-S vaccine with various schedules. In: Regamery RH, editor. Symposium Series on Immunobiological Standards, 21. Karger: Bsil; 1974. p. 231–9. [4] Bahmanyar M, Fayaz A, Nour-Salehi S, Bahmanyar M, Koprowski H. Successful protection of humans exposed to rabies infection: post-exposure treatment with the new human diploid cell rabies vaccine and antirabies serum. JAMA 1976;236:2751–4. [5] Fayaz A, Simani S, Nour-Salehi SD, Bahmanyar M. Booster effect of human diploid cell antirabies vaccine in previously treated persons. J Am Med Assoc 1981;248:2334–5. [6] Smith JS, Yager PA, Baer MA. Rapid fluorescent focus inhibition test (RFFIT) for determining rabies virus-neutralizing antibody. In: Meslin FX, Kaplan MM, Koprowski H, editors. Laboratory technique in rabies. 4th ed. Geneva: WHO; 1996. [7] Thraenhart O, Kreuzfelder E, Hillebrandt M, Marcus I, Ramakrishnan K, Fu ZF, Dietzschold B. Long-term humoral and cellular immunity after vaccination with cell culture rabies vaccines. Clin Immunopathol 1994;71:287–92.
3745
[8] Briggs DJ, Schwenke FJR. Longevity of rabies antibody titre in recipients of human diploid cell rabies vaccine. Vaccine 1992;10(2.). [9] Suwansrinon K, Wild H, Benjavongleulchai M, Banjongkasaena U, Lertjarutorn S. Survival of neutralizing antibody in previously rabies vaccinated subjects. Vaccines 2006;24:3878–80. [10] Sabchareon A, Chantavanich P, Pasuralertsakul S, Pojjaroen-Anant C, Prarinyanupharb V, Attanath P, et al. Persistence of antibodies in children after intradermal or intramuscular administration of preexposure primary and booster immunization with purified Vero cell rabies vaccine. Pediatr Infect Dis J 1998;17:1001–7. [11] Strady A, Lang J, Lienard M, Blondeau C, Jaussaud R, Plotkin SA, et al. Antibody persistence following preexposure regimens of cell culture rabies vaccine: 10-year follow up and proposal for a new booster policy. J Infect Dis 1998;177:1290–5. [12] WHO Technical report series 931, WHO Expert Consultation on Rabies, first report 2004: Geneva, Switzerland.
Contents lists available at ScienceDirect
Vaccine journal homepage: www.elsevier.com/locate/vaccine
Antibody persistence, 32 years after post-exposure prophylaxis with human diploid cell rabies vaccine (HDCV) Ahmad Fayaz ∗ , Susan Simani, Alireza Janani, Firouzeh Farahtaj, Peyvand Biglari, Nader Howeizi, Nasser Eslami WHO-Collaborating Center for Reference & Research on Rabies, Pasteur Institute of Iran, Tehran, Iran
a r t i c l e
i n f o
Article history: Received 5 January 2011 Received in revised form 7 March 2011 Accepted 16 March 2011 Available online 31 March 2011 Keywords: Rabies Post-exposure prophylaxis Antibody persistence
a b s t r a c t In 1975–1976 forty-five persons severely bitten by rabid wolves and dogs in Iran were treated successfully against rabies with HDCV. In this study contact was made with 26 of 45 above persons, 32 years after their initial treatment and all had rabies neutralizing antibody ranging from 0.3 to 2.69 IU/ml of serum. Of the 26 persons, 17 had received a booster dose of HDCV, 28 years ago and the remaining 9 persons, who had not received any booster since the initial treatment, were given one booster dose of HDCV. All 9 of these patients developed an anamnestic response after their booster inoculation. This study confirms the persistence of rabies neutralizing antibody in persons that received post-exposure vaccination with HDCV, 32 years previously. Furthermore, a single booster inoculation with HDCV resulted in anamnestic response in all individuals. © 2011 Elsevier Ltd. All rights reserved.
1. Introduction Rabies is an invariably fatal disease in humans and animals once clinical symptoms are evident. It is also a unique disease in that patients can be protected from developing clinical disease, even after exposure, through the administration of post-exposure prophylaxis (PEP). This remarkable fact was discovered by Louis Pasteur and Emil Roux in 1885 when they began to successfully save the lives of bitten patients by vaccinating them with increasingly virulent doses of spinal cord from infected rabbits. In the decade following Pasteur and Roux’s first treatment for exposed patients, rabies vaccines gradually improved but they were still produced in vivo by inoculating animals with live rabies virus and harvesting their infected brain material until the late twentieth century when for the first time, rabies vaccines were successfully produced in cell cultures. Human diploid cell rabies vaccine (HDCV) was the first globally successful cell culture rabies vaccine and must be credited for saving the lives of millions and perhaps even billions of lives since it was developed and first marketed in the 1970s. HDCV was an entirely new concept in the manufacture of rabies vaccine and as such its efficacy was unknown. The first experimental batch of the vaccine was produced and tested in animals and finally in human volunteers and was found to be
∗ Corresponding author at: No. 69, 12th Farvardin Ave., Pasteur Ave., Pasteur Square, Tehran 1316943551, Iran. Tel.: +98 21 66403496; fax: +98 21 66480777. E-mail address: [email protected] (A. Fayaz). 0264-410X/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.vaccine.2011.03.048
highly immunogenic; the Institut Merieux in Lyon, France, agreed then to produce large quantities of HDCV for clinical trials in Iran [1,2]. Convinced of the safety of the HDCV and promptness of the antigenic response in humans, and with the consent of Iranian responsible authorities, HDCV was used for the first time in Iran for PEP in human as follows: in 1975–1976, 45 persons that were severely bitten by rabid wolves and dogs received PEP in what was to become the backbone of the modern PEP regimen. All of these patients had received multiple wounds and were at risk of contracting rabies if not treated. The wounds were inflicted by six dogs and two wolves in rural areas of north western part of Iran between June 1975 and January 1976. All animals were confirmed to be rabid by immunofluorescent test of brain tissue and where possible, titration of the virus present in the salivary glands of the animals was conducted. All patients received the first dose of vaccine simultaneously or within one hour after being administered heterologous anti rabies serum. The complete course of HDCV treatment consisted of 5 doses inoculated subcutaneously on days 0, 3, 7, 14, 30 and a booster dose on day 90. At the end of 2007, after several trips to different rural areas in Iran, we were able to locate 26 of 45 patients that were exposed and initially received PEP, including the newly developed HDCV, 32 years ago. In this study, we report on the levels of rabies virus neutralizing antibody (RVNA) present in their blood and their response to one booster dose of HDCV.
A. Fayaz et al. / Vaccine 29 (2011) 3742–3745
3743
Table 1 Exposed patients groups according to the animal and location of the attack and the date of exposure. Group
Species
A B C D E
Dog Dog Dog Wolf Dog
F G
Dog Wolf
H
Dog
a b c
Village
Kharileh Seylab Cheverin Aghbulagh Baderlou Oghul Beyk Qara-Boulagh Alishtar Hossein-Abad Bagher-Abad Darrehchin Chakmikush Bouryabad
Date of attack
No. of persons bitten
June 9, 1975 July 19, 1975 September 12, 1975 October 20, 1975 October 26, 1975 October 26, 1975 October 27, 1975 October 31 1975 November 27, 1975 November 27, 1975 January 19, 1976 January 19, 1976 January 20, 1976
7 1 11 7 1 1 2 6 1 1 4
Rabies confirmationa Brainb
Salviac
+ + + + +
NA NA NA 5.6 NA
+ +
5.0 5.1
+
4.1
3
NA indicates not available; + indicates presence of rabies antigen. Presence of rabies antigen in brain tissue demonstrated by direct immunofluorescence. Rabies virus titers of salivary glands, given in median lethal dose for a mouse/0.03 ml (log 10).
2. Materials and methods
subjects who did not receive any booster dose since 32 years ago.
2.1. Historical backgrounds 2.4. Serology The protocol for a detailed field trial to assess the immunogenicity of the HDCV was established by an international scientific seminar held in Geneva in 1973, and WHO-Collaborating Centre for Reference & Research on Rabies in Tehran was entrusted with the clinical trials for the new HDCV [1]. The high level of specific antibody response of human volunteers vaccinated with one to five doses of HDCV, essentially without side effects, had been confirmed by Bahmanyar [3]. In 1975–1976, the event of 45 persons being bitten by rabid dogs and wolves occurred and provided an opportunity to use the newly developed HDCV in conjunction with heterologous anti-rabies serum for the first time in history a new regimen for PEP in patients exposed to known rabid animals. The 45 exposed patients were divided in to 8 groups according to Table 1. The number of wounds per persons varied from a single penetration wound to 25 multiple severe lacerations about the face and head. This treatment resulted in protection of all individuals against rabies [4]. In 1979, contact was established with 27 of 45 mentioned persons four years after their severe exposure to rabies virus and successful protection. During that time these persons maintained rabies neutralizing antibody at the level of 2–91 IU/ml of serum. A single booster inoculation of HDCV, resulted in the increase of neutralizing antibodies [5]. 2.2. Patients In 2007, we studied the data concerning 26 of the 45 mentioned group, of which, 17 belonged to the persons who received PEP (in 1975–1976) and one booster dose in 1979 and the rest (9 persons) had not received any booster up to 2007. So, for the latter 9 persons, the titer of rabies neutralizing antibody was determined before and after receiving a single dose of booster HDCV. According to the biting animals, the 26 exposed persons were belonged to the 5 groups A, C, D, F and H (Table 2). 2.3. Vaccine Human diploid cell rabies vaccine produced by Sanofi Pasteur, Lyon, France was used in the study. Its batch number was Z1037-1, prepared from supernatant of Human Embryonic Lung Fibroblast Culture W138, infected with the Pitman Moore strain of rabies virus. A single dose of HDCV was only administered to 9 of 26
Blood samples were obtained from 26 of 45 exposed persons who were treated 32 years ago. Of the 26 exposed individuals nine received one booster dose of HDCV and their blood samples were obtained ten days after the booster. In our lab, serum samples were separated, inactivated at 56 ◦ C and stored at −20 ◦ C until titration. Antibody persistence was evaluated by titration of neutralizing antibodies with Rapid Fluorescent Focus Inhibition Test (RFFIT) [6]. 3. Results Twenty-six of the 45 persons that had received PEP with heterologous anti-rabies sera and the “then” newly developed HDCV in the first clinical field trial conducted between1975 and 1976 were located. The original 45 subjects had been initially separated into 8 groups depending on the animals that initially inflicted the wounds (Table 1). The 26 persons that were contacted in 2007 were originally members of groups A, C, D, F and H as follows (Table 2): (1) 3 people from group A, wounded by a laboratory-confirmed rabid dog in June 1975. (2) 7 persons from group C with deep wounds, bitten by a laboratory-confirmed rabid dog in September 1975. (3) 6 persons from group D with wounds in their heads and faces, bitten by a laboratory-confirmed rabid wolf in October 1975. The viral titer in the salivary glands of this wolf had been 105.6. (4) 5 people from group F wounded by a laboratory-confirmed rabid dog with salivary glands viral titer of 105 in November 1975. (5) 5 persons from group H bitten by a laboratory-confirmed rabid dog with salivary glands viral titer of 104.1 in January 1976. All of the 26 persons had RVNA levels ranging from 0.3 to 2.69 IU/ml, four of these patients had received two doses of Vero rabies vaccine after re-exposure in 2005. The RVNA titer of the 9 subjects who had received no rabies vaccine during the past 32 years ranged from between 0.3 and 0.98 IU/ml. Ten days after having received one booster of HDCV in 2007, the range of RVNA in these nine persons was between 2.6 and 20 IU/ml.
3744
A. Fayaz et al. / Vaccine 29 (2011) 3742–3745
Table 2 Age and sex of patients, biting animal and the date that received their initial PEP and the dates that patients received one additional dose of HDCV. Rabies virus neutralizing antibody titers are expressed in IU/ml of serum. Group
No.
Patient sex/age yra
Biting animal
Date of PEP
Antibody titers 32 years After PEP: IU/ml of serum 26 Individuals
9 of 26 individuals who received HDCV booster in 2007
A
1 2 3
M/18 F/20 M/11
Dog // //
June 1975 // //
0.5b 0.3b 0.3b
C
4 5 6 7 8 9 10
M/10 F/23 M/7 M/8 M/7 M/9 M/11
Dog // // // // // //
September 1975 // // // // // //
0.98 0.3 0.98 0.3b 0.3b 0.3b 1.0b
20 20 20
D
11 12 13 14 15 16
M/19 F/35 F/45 M/45 M/7 M/40
Wolf // // // // //
October 1975 // // // // //
0.3 0.91 0.75 0. 3 0.79 0.9
2.6 10.4 5.5 3.2 8.3 3.5
F
17 18 19 20 21
F/7 F/12 M/8 M/3 M/4
Dog // // // //
November 1975 // // // //
2.18c 2.69c 2.1c 0.55b 1.2c
H
22 23 24 25 26
M/15 M/15 M/16 M/12 M/16
Dog // // // //
January 1976 // // // //
0.31b 1.1b 0.95b 0.9b 1.0b
a b c
Yr age: at the time of exposure. Received HDCV booster in 1979. Received HDCV booster in 1979 and 2 doses of Vero Rabies Vaccine in 2005 after re-exposure.
The remaining 17 persons who had received one dose of HDCV vaccine 4 years after original treatment (28 years ago), had RVNA titers ranging between 1.2 to 2.69 IU/ml at the time of this study although, four of these subjects received two shots of Vero rabies vaccine 3-days, apart during 2005 after being exposed to suspect rabid animals. The RVNA titer of these four patients ranged between 1.2 and 2.69 IU/ml. 4. Discussion In 1980, we reported adequate RVNA titers in 27 patients that had received PEP with HDCV and Equine Rabies Immunoglobulin four years earlier and after a single booster inoculation of HDCV in 1980, resulted in a sharp increase in the level of RVNA [5]. In 1994, Traenhart reported the existence of humoral and cellular immunity as long as 14 years after original vaccination. All 18 subjects in Traenhart’s study had values ≥0.5 IU/ml measured by RFFIT [7]. Longevity of rabies neutralizing antibody after administration of HDCV was studied by Briggs et al. [8]. Suwansrinan et al. carried out a prospective study on 118 rabies vaccine recipients who had received pre- or post-exposure regiments with PVRV or HDCV, 5–21 years previously. Rabies neutralizing antibody was detectable in the sera of all the subjects [9]. This study examined the anamnestic response of the patients involved in the first field study using a modern cell culture rabies vaccine, HDCV, which would eventually replace the use of rabies vaccines made in the brain tissue of infected animals. The field study, conducted in 1975–1976 in patients from rural Iran, was the first time in history that patients exposed to confirmed rabid animals were treated with this new type of vaccine using a reduced PEP
regimen. Therefore, the data in this paper represent the most accurate information on the longevity of RVNA titers and the ability for a patient to evoke an anamnestic response after vaccination with HDCV. The data confirms the persistence of rabies neutralizing antibody for up to 32 years after vaccination with HDCV. Furthermore one booster dose of HDCV to 9 subjects who did not received any booster of rabies vaccine during 32 years, resulted in an increase in the level of RVNA proving that these patients were able to develop an anamnestic response. Due to the fact that other reports have demonstrated the equivalence of immunity for other WHO prequalified cell culture rabies vaccines. These results indicate that the persons who have previously received PEP even 32 years previously will develop an anamnestic response to a single booster dose of a cell culture rabies vaccine [10–11]. The level of antibody response after vaccination varies in different subjects, but the lowest titer correlated with protection recommended by WHO is 0.5 IU/ml [12] and in our group studied the titer level after booster injection was significantly higher. Acknowledgments We are very grateful to Dr. Deborah J. Briggs, executive director of the global Alliance for Rabies Control, for proof reading and contributing to the manuscript and Dr. Anis Jafari from Pasteur Institute of Iran for critical review of the manuscript. References [1] Sikes RK, Cleary WF, Koprowsky H, Wiktor TJ, Kaplan MM. Effective protection of monkeys against death from street virus by post-exposure administration of tissue culture rabies vaccine. Bull WHO 1971;45:1–11. [2] Wiktor TJ, Plotkin S, Grella DW. Human cell culture rabies vaccine: antibody response in man. JAMA 1973;224:1170–1.
A. Fayaz et al. / Vaccine 29 (2011) 3742–3745 [3] Bahmanyar M. Results of antibody profiles in man vaccinated with HDC-S vaccine with various schedules. In: Regamery RH, editor. Symposium Series on Immunobiological Standards, 21. Karger: Bsil; 1974. p. 231–9. [4] Bahmanyar M, Fayaz A, Nour-Salehi S, Bahmanyar M, Koprowski H. Successful protection of humans exposed to rabies infection: post-exposure treatment with the new human diploid cell rabies vaccine and antirabies serum. JAMA 1976;236:2751–4. [5] Fayaz A, Simani S, Nour-Salehi SD, Bahmanyar M. Booster effect of human diploid cell antirabies vaccine in previously treated persons. J Am Med Assoc 1981;248:2334–5. [6] Smith JS, Yager PA, Baer MA. Rapid fluorescent focus inhibition test (RFFIT) for determining rabies virus-neutralizing antibody. In: Meslin FX, Kaplan MM, Koprowski H, editors. Laboratory technique in rabies. 4th ed. Geneva: WHO; 1996. [7] Thraenhart O, Kreuzfelder E, Hillebrandt M, Marcus I, Ramakrishnan K, Fu ZF, Dietzschold B. Long-term humoral and cellular immunity after vaccination with cell culture rabies vaccines. Clin Immunopathol 1994;71:287–92.
3745
[8] Briggs DJ, Schwenke FJR. Longevity of rabies antibody titre in recipients of human diploid cell rabies vaccine. Vaccine 1992;10(2.). [9] Suwansrinon K, Wild H, Benjavongleulchai M, Banjongkasaena U, Lertjarutorn S. Survival of neutralizing antibody in previously rabies vaccinated subjects. Vaccines 2006;24:3878–80. [10] Sabchareon A, Chantavanich P, Pasuralertsakul S, Pojjaroen-Anant C, Prarinyanupharb V, Attanath P, et al. Persistence of antibodies in children after intradermal or intramuscular administration of preexposure primary and booster immunization with purified Vero cell rabies vaccine. Pediatr Infect Dis J 1998;17:1001–7. [11] Strady A, Lang J, Lienard M, Blondeau C, Jaussaud R, Plotkin SA, et al. Antibody persistence following preexposure regimens of cell culture rabies vaccine: 10-year follow up and proposal for a new booster policy. J Infect Dis 1998;177:1290–5. [12] WHO Technical report series 931, WHO Expert Consultation on Rabies, first report 2004: Geneva, Switzerland.