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Oral fluid detection of hepatitis B vaccine-induced
antibodies can improve vaccination programmes.
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| Article Type: | Report |
| Subject: |
Antibodies
(Physiological aspects) Antibodies (Research) Viral antibodies (Physiological aspects) Viral antibodies (Research) Hepatitis B vaccine (Health aspects) Hepatitis B vaccine (Research) Vaccination (Health aspects) |
| Authors: |
Simani, Omphile E. Francois, Guido Burnett, Rosemary J. Meheus, Andre Basetse, Herbert R. Mphahlele, M. Jeffrey |
| Pub Date: | 08/01/2008 |
| Publication: | Name: South African Medical Journal Publisher: South African Medical Association Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2008 South African Medical Association ISSN: 0256-9574 |
| Issue: | Date: August, 2008 Source Volume: 98 Source Issue: 8 |
| Topic: | Event Code: 310 Science & research |
| Product: | Product Code: 8000146 Vaccination & Immunization NAICS Code: 621999 All Other Miscellaneous Ambulatory Health Care Services |
| Geographic: | Geographic Scope: South Africa Geographic Code: 6SOUT South Africa |
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| Accession Number: | 204611547 |
| Full Text: |
To the Editor: About 387 million people (over 5% of the global
population) are chronically infected with the hepatitis B virus (HBV).
(1) The World Health Organization (WHO) plans to contain the burden of
HBV infections by means of universal vaccination programmes for infants
and adolescents. The vaccine may be almost universally available to
children within the next few years. (2) A major drawback of monitoring
immunity to the hepatitis B vaccine or HBV infection is the need for a
blood specimen to detect hepatitis B surface antibodies (antiHBs).
Collecting blood is by needle, and is often painful and traumatic for
babies, children and adults with poor venous access, so non-invasive
sampling would be an ideal alternative. Several oral fluid collection devices exist. (3-7) The OraSure (OraSure Technologies Inc., USA), a non-invasive cotton pad impregnated with gelatine, salts (sodium chloride, citric acid, sodium benzoate, potassium sorbate, and sodium hydroxide to give pH 6.5) and deionised water is approved for use in humans by the USA's Food and Drug Administration (FDA) and is licensed for collection of oral mucosal transudate (OMT) for anti-HIV testing. (8) As OMT is a serous fluid rich in immunoglubulins (IgG, IgM and IgA), it is possible to test for antibodies induced by infections of public health importance such as hepatitis A virus (HAV), HBV, hepatitis C virus (HCV), (7,9,10) human papillomavirus type 1611 and many others. (6) Samples can also be used to investigate the presence of hepatitis B surface antigen. (12) We aimed to assess the OraSure device for collection of OMT samples; modify a serum-based commercial enzyme-linked immunosorbent assay (ELISA) kit (Murex anti-HBs ELISA, Murex Biotech Limited) for the detection of anti-HBs from OMT specimens; and evaluate the suitability of OMT as an alternative to blood for detecting anti-HBs induced by the hepatitis B vaccine. Methods A total of 67 paired serum and OMT specimens were collected from vaccinated health care workers (HCWs) at Dr George Mukhari Hospital, Medunsa complex. In addition, 5 HCWs previously identified as having undetectable anti-HBs despite hepatitis B vaccination were used as negative controls. An OMT sample and [less than or equal to] 3 ml of blood (using a 5 ml syringe and Vacutainer tubes) were collected after obtaining consent from each HCW. Blood samples were collected, processed and stored as previously described. (13) To obtain OMT samples, the OraSure pad was placed for 2 minutes between the lower gum and inner cheek. The osmotic action of the pad draws antibodies from the mucosal tissues. Antibodies move from the capillaries to interstitial fluid and across the mucosa. The collection device is immediately placed into a preservative solution, where it remains stable for up to 21 days when stored at 20-37[degrees]C, or at room temperature. All serum specimens were tested for antiHBs with automated AUSAB IMx assay (13) and manual Murex anti-HBs ELISA, following manufacturers' instructions. The OMT specimens were tested only with Murex ELISA, after in-house experiments to modify and optimise the assay for detection of antibodies from oral fluid (results not shown). Results The AUSAB IMx assay (used as the gold standard) accurately determines anti-HBs to approximately 1 mIU/ml. Using this assay, the sera of 65 (97.0%) of 67 hepatitis B-vaccinated HCWs were found to be anti-HBs positive, and 2 (3.0%) were antiHBs negative (Table I). None of the 5 controls tested positive for anti-HBs with AUSAB IMx assay. Testing with the AUSAB IMx assay therefore identified 65 seropositive for anti-HBs, and 7 negatives. The 65 anti-HBs positives had anti-HBs titres ranging from 1.2 to >1 000 mIU/ml. The anti-HBs results from the AUSAB IMx assay were compared with those obtained from the serum samples tested with Murex anti-HBs ELISA (Table IA). The Murex assay detected anti-HBs in 64 (98.5%) of the 65 positive sera, and in none of the 7 negative sera, leading to one false negative (the anti-HBs titre of this sample was 1.2 mIU/ml, which was below the cut-off value ([greater than or equal to] 5 mIU/ml) for the Murex assay). The Murex assay therefore yielded a sensitivity of 98.5% (i.e. 64/65) and specificity of 100% (i.e. 7/7). The anti-HBs results from the AUSAB IMx assay were compared with the Murex ELISA on OMT samples. All 67 OMT specimens from vaccinated HCWs were reactive for anti-HBs using the Murex assay, including the 2 identified as anti-HBs negative by the AUSAB IMx assay. Therefore, the OMT-based testing resulted in 2 false positives (Table IB). However, all 5 OMT specimens from the control group were non-reactive for anti-HBs. The Murex assay on OMT samples showed a sensitivity of 100% and specificity of 71.4%. Discussion This study was supported in part by grants from the National Research Foundation and the Poliomyelitis Research Foundation (both local). Accepted 10 April 2008. References (1.) Burnett RJ, Francois G, Kew MC, et al. Hepatitis B virus and human immunodeficiency virus co-infection in sub-Saharan Africa: A call for further investigation. Liver Int 2005; 25: 1-12. (2.) Kane MA, Brooks A. New immunization initiatives and progress toward the global control of hepatitis B. Curr Opin Infect Dis 2002; 15: 465-469. (3.) Parry JV, Perry KR, Mortimer PP. Sensitive assays for viral antibodies in saliva: an alternative to tests on serum. Lancet 1987; 2: 72-75. (4.) Connell JA, Parry VJ, Mortimer PP, Duncan J. Novel assay for the detection of immunoglobulin G antihuman immunodeficiency virus in untreated saliva and urine. J Med Virol 1993; 41: 159-164. (5.) Allwright S, Bradley S, Long J, Barry J, Thornton L, Parry JV. Prevalence of antibodies to hepatitis B, hepatitis C, and HIV and risk factors in Irish prisoners: results of a national cross sectional survey. BMJ 2000; 321: 78-82. (6.) Vyse AJ, Cohen BJ, Ramsay ME. A comparison of oral fluid collection devices for use in the surveillance of virus diseases in children. Public Health 2001; 115: 201-207. (7.) Cameron SO, Carman WF. The use of the OraSure collection device for hepatitis testing in health care settings. J Clin Virol 2005; 34 (Suppl 1): S22-S28. (8.) Gallo D, George JR, Fitchen JH, Goldstein AS, Hindahl MS (OraSure HIV Clinical Trials Group). Evaluation of a system using oral mucosal transudate for HIV-1 antibody screening and confirmatory testing. JAMA 1997; 277: 251-258. (9.) Sherman KE, Creager RL, O'Brien J, Sargent S, Piacentini S, Thieme T. The use of oral fluid for hepatitis C antibody screening. Am J Gastroenterol 1994; 89: 2025-2027. (10.) George JR, Piacentini SC, McGrath BA, Bodin GF, Kenny CA. Diagnosis of HIV, hepatitis B, and hepatitis C in a high risk population using oral fluid. Presented at the 6th Conference on Retroviruses and Opportunistic Infections, Chicago, Illinois, 31 Jan - 4 Feb 1999. (11.) Marais DJ, Best JM, Rose RC, et al. Oral antibodies to human papillomavirus type 16 in women with cervical neoplasia. J Med Virol 2001; 65: 149-154. (12.) Hutse V, Verhaegen E, De Cock L, et al. Oral fluid as a medium for the detection of hepatitis B surface antigen. J Med Virol 2005; 77: 53-56. (13.) Tsebe KV, Burnett RJ, Hlungwani NP, Sibara MM, Venter PA, Mphahlele MJ. The first five years of universal hepatitis B vaccination in South Africa: evidence for elimination of HBsAg carriage in under-5-year-olds. Vaccine 2001; 19(28-29): 3919-3926. (14.) Ferri RS. Oral mucosal transudate testing for HIV-1 antibodies: a clinical update. J Assoc Nurses AIDS Care 1998; 9: 68-72. (15.) Nokes DJ, Enquselassie F, Vyse A, Nigatu W, Cutts FT, Brown DW. An evaluation of oralfluid collection devices for the determination of rubella antibody status in a rural Ethiopian community. Trans R Soc Trop Med Hyg 1998; 92: 679-685. (16.) Nokes DJ, Enquselassie F, Nigatu W, et al. Has oral fluid the potential to replace serum for the evaluation of population immunity levels? A study of measles, rubella and hepatitis B in rural Ethiopia. Bull World Health Organ 2001; 79: 588-595. Accepted 10 April 2008. HIV and Hepatitis Research Unit, Department of Virology, University of Limpopo, Medunsa Campus, Pretoria Rosemary J Burnett, MPH Omphile E Simani, MSc Department of Epidemiology and Social Medicine, University of Antwerpen, Belgium Guido Francois, MSc, PhD Andre Meheus, MD, PhD National Health Laboratory Service, Dr George Mukhari Tertiary Laboratory, Department of Virology, University of Limpopo, Medunsa Campus Herbert R Basetse, DTech HIV and Hepatitis Research Unit and National Health Laboratory Service, Dr George Mukhari Tertiary Laboratory, Department of Virology, University of Limpopo, Medunsa Campus M Jeffrey Mphahlele, MSc, PhD Corresponding author: M J Mphahlele (jmphahlele@medunsa.ac.za) Table I. Detection of anti-HBs from serum and OMT samples and
assay validation results using the AUSAB IMx as gold standard assay
Positive Negative Total
A: AUSAB IMx sera v. Murex sera assay
Positive 64 0 64
Negative 1 7 8
Total 65 7 72
B: AUSAB IMx sera v. Murex OMT assay
Positive 65 2 67
Negative 0 5 5
Total 65 7 72
Sens Spec
A: AUSAB IMx sera v. Murex sera assay
Positive
Negative 98.5 100
Total
B: AUSAB IMx sera v. Murex OMT assay
Positive
Negative 100 71.4
Total
PPV NPV
A: AUSAB IMx sera v. Murex sera assay
Positive
Negative 100 87.5
Total
B: AUSAB IMx sera v. Murex OMT assay
Positive
Negative 97.0 100
Total
Sens = sensitivity (true positive/true positive + false negative);
Spec = specificity (true negative/true negative + false positive);
PPV = positive predictive value (true positive/true
positive + false positive); NPV = negative predictive value
(true negative/true negative + false negative). |
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