Performance of commercially available HIV Rapid and HIV ELISA test kits on post HIV vaccination samples to evaluate Vaccine Induced Sero-Reactivity 1, 1 Stevens , Bashir 2 Farah , 2 Mwangi , 2 Wangui , 1 Schmidt , 1 Laufer , 2 Anzala Paramesh Chetty Gwynn Irene Stella Claudia Dagna Omu 1 International AIDS Vaccine Initiative (IAVI), New York, USA and 2 Kenyan AIDS Vaccine Initiative (KAVI), Nairobi Kenya BACKGROUND METHODS RESULTS Phase 1 preventative HIV vaccine clinical trials enrol low risk HIV negative volunteers. Most HIV vaccine immunogenes encode proteins mainly from the env, gag, pol, and nef regions and are designed to induce the production of protective antibodies. The elicited vaccine induced After un-blinding 31/32 of the vaccine recipients were shown to express VISR. The 31 volunteers that received Table 1: KAVI Section of Study Design Group Vaccines Dose test kits’ results. Delineation of these seropositive results among vaccine recipients has resulted F crucial in distinguishing VISP from true HIV infection. Month 0 Month 3 Month 6 Table 4. Comparison of test kit Results placebo) E RNA detection. Determining the best suited HIV testing algorithm for a particular product/trial is (active/ G H Ad26.ENVA.01, Ad35-ENV 5x1010 vp/ 5x1010 vp Ad35-ENV, Ad26.ENVA.01 5x1010 vp/ 5x1010 vp Ad26.ENVA.01, Ad26.ENVA.01 5x1010 vp/ 5x1010 vp Ad35-ENV, Ad35ENV 5x1010 vp/ 5x1010 vp 10 Ad26 Ad35 - Ad35 Ad26 - Ad26 Ad26 - Ad35 Ad35 - (8/2) 10 (8/2) 10 (8/2) 10 (8/2) 40 Total 32/8 Table 2: Vaccination visits and HIV testing time points METHODS HIV-uninfected study volunteers were randomised to receive either the Ad26-ENVA or Ad35-ENV Ad35-ENV: Recombinant adenovirus serotype 35 vector vaccine is a recombinant replicationincompetent product that encodes the HIV-1 subtype Agp140 env gene. (Figure 1) Ad26.ENV.01 (rAd26): Recombinant adenovirus serotype 26 vector vaccine is a recombinant replication-deficient product composed of an adenovirus serotype 26 vector that encodes the HIV-1 Clade A Env glycoprotein 140 (strain 92rw020)(Figure 1). product, or both products or placebo in a prime-boost regimen as in Table 1. Samples stored from 32 vaccine and 8 placebo recipients at 2 months and 9 months post last the investigational product and expressed VISR had HIV-1 RNA PCR confirmatory tests conducted and all test results were undetectable for HIV-1 wild type infection. N antibodies (VISP) in the absence of HIV infection can confound the interpretation of standard HIV in the use of more complicated HIV testing algorithms and laboratory techniques, such as HIV-1 Figure 1: Vaccine Inserts Vaccine recipients showed higher percentages of reactive results using the 4th generation (BioMerieux Vironostika Ag/Ab and Mini-Vidas Ultra Duo Ag/Ab, 96.9%) versus 3rd generation (Alere Determine HIV 1/2, Table 3: Details of Kit Inserts vaccination were tested on 4 different HIV test kits at the KAVI research centre in Nairobi, Kenya. Details Figure 2: On study HIV testing Algorithm 37.5% & 9.4%; Trinity Uni-Gold HIV, 50% & 3.1%) HIV test kits (Table 4). No placebo recipients showed any VISR. of the test kits can be found in Table 3. VISR declined over time, possibly due to waning of the vaccine induced antibody titre. Samples from 2 months and 9 months post last vaccination visits were tested using the HIV Rapid test kits (Alere Determine HIV-1/2 and Trinity Uni-Gold HIV) and BioMerieux Vironostika HIV Ag/Ab Elisa kits. . CONCLUSION Samples only from 9 months post last vaccination were tested on the HIV ELISA Mini-Vidas HIV Duo Ultra (HIV5) Ag/Ab test kit and. Data for 2 months post last vaccination were already available for the Selection of appropriate HIV test kits when developing a suitable HIV testing algorithm(s) to support a Vironostika HIV Ag/Ab test kit as part of the on study HIV testing algorithm. preventative HIV vaccine trial can be challenging. 3rd generation HIV Rapid test kits were much less sensitive, detecting VISR less often when compared to 4th Generation ELISA kits. Post vaccination *Only available information from package insert for Alere Determine HIV-1/2 is the sensitivity Profile as listed below: HIV-1 Positive 100% HIV-2 Positive 100% HIV-1 Subtype A-G 100% HIV-1 Group O 100% samples from previous HIV vaccine trials with similar products are useful when designing HIV testing algorithms for subsequent trials. The occurrence of VISR is dependent on the HIV gene inserts in both the test kit and the investigational product. The above analysis indicated that HIV vaccines that carry the ENV gene tend to trigger VISR, particularly when using a 4th generation HIV ELISA test kit. Optimally an HIV testing algorithm would include HIV test kits that only detect HIV-1 wild type infection Kanya AIDS Vaccine Initiative (KAVI) Clinical Team KAVI Laboratory Team (Left to right) I. Mwangi. B. Farah, S.Ogola, R. Chirchir And R. Langat REFERENCES 1 2 Etienne Karita et al., Safety in a Phase 1 randomized, doubleblind, placebo-controlled trial evaluating two adenovirus HIV vaccines in three different geographic regions (IAVIB003/IPCAVD-004/HVTN091 trial) Jill Gilmour et al., Immunogenicity of homologous and heterologous regimens of Ad26-EnvA.01 and Ad35EnvA HIV vaccines in HIVuninfected volunteers in the US and Africa and not VISR in a cost effective, timely manner to mitigate anxiety and potential social harm to the volunteer. In Kenya / Africa setting community based HIV testing is done using the HIV Rapid tests. Collecting post-trial follow-up data on VISR is important to better characterize VISR persistence and to avoid potential VISR results through community-based HIV testing of volunteers. ACKNOWLEDGEMENTS Thanks to all the dedicated trial participants, the staff at the clinical sites and immunology support laboratories. Thanks to EMMES and SCHARP for data analysis and clinical trial database support. The B003/IPCAVD004/HVTN091 clinical trial was conducted at the Brigham and Women's Hospital, Harvard Medical School, USA; Projet San Francisco, Rwanda; Zambia HIV Research Group, Zambia; Kenya AIDS Vaccine Initiative, Kenya; The Desmond Tutu HIV Centre Institute of Infectious Disease and Molecular Medicine Faculty of Health Sciences, South Africa; Perinatal HIV Research Unit, South Africa; The Aurum Institute for Health Research, South Africa; in collaboration with the Beth Israel Deaconess Medical Center, Harvard Medical School, USA; the Fred Hutchinson Cancer Research Center, USA; the HIV Vaccine Trial Network, USA; The Ragon Institute, USA; the National Institute of Allergy and Infectious Diseases, USA and Crucell Holland BV, Netherland.