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Malaysian Society of Infectious Diseases & Chemotherapy

Guidelines for Adult Immunisation

Content

Message from Editor

Editorial Panel

Adult Immunisation Schedule

Contraindications and Special Considerations

Temporary Deferral of Immunisation

Route and Site of Administration

Post Vaccination

Anaphylaxis

Vaccine Storage and Disposal of Vaccines

Vaccine Combinations

Multiple Vaccinations

Adverse Event Following Immunisation (AEFI)

Immunosenescence

Cholera

COVID-19

Dengue

Diphtheria

Tetanus

Pertussis

Haemophilus influenzae type b

Hepatitis A

Hepatitis B

Human Papillomavirus (HPV)

Influenza

Japanese Encephalitis (JE)

Measles

Mumps

Rubella

Meningococcal Disease

Mpox

Pneumococcal Disease

Poliomyelitis

Rabies

Respiratory Syncytial Virus (RSV)

Typhoid Fever

Chickenpox (Varicella)

Yellow Fever

Shingles (Zoster)

Passive Immunisation

Avian Influenza

Chikungunya

Clostridioides difficile

Ebola

Human Immunodeficiency Virus (HIV)

Malaria

Zika

Adults Who Missed Childhood Immunisation

Older Adults and Patients With Chronic Ilnesses

Healthcare workers

Human Immunodeficiency Virus (HIV)

Immunocompromised Patients

Miscellaneous Groups

Travelers

Vets & Animal Handlers

Abbreviations

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Future Vaccines

Human Immunodeficiency Virus (HIV)

In this chapter:

Introduction

HIV remains a major global public health issue, particularly in low- and middle-income countries. The HIV-related death toll is estimated at 44.1 million to date. Sub-Saharan Africa is the region most impacted by the virus, with 1 in 25 adults living with HIV. There were an estimated 40.8 million people living with HIV at the end of 2024, 65% of whom are in the WHO African Region. In 2024, an estimated 630,000 people died from HIV-related causes and an estimated 1.3 million people acquired HIV.

In Malaysia, the first HIV case was recorded in 1986. The current cumulative number of reported HIV cases is 131,815; the cumulative number of reported AIDS cases is 30,174; while the total number of deaths related to HIV/AIDS is 62,226. As of 2023, the estimated number of people living with HIV (PLHIV) was 86,142, where about 90% of cases are males and 69,589 (81%) were aware of their status and had been notified through the national surveillance system.  By December 2022, 68% of the reported PLHIV were receiving antiretroviral treatment (ART). More than 70% of new HIV infections are reported among people 20 to 39 years old, and approximately 14% among those aged 13-19 years old.

Vaccines

While ART has dramatically improved the quality of life and life expectancy for people with HIV, a vaccine remains the most sustainable solution for prevention. Since 1987, more than 30 HIV candidate vaccines have been tested in approximately 60 Phase I/II trials. Most of these trials have been conducted in the United States and Europe, but several have also been conducted in developing countries in Africa, South America and Asia. The results have confirmed the safety of the vaccines and have provided important scientific information to develop newer generations of candidate vaccines. 

As of late 2025, after more than 35 years of intensive vaccine research, various approaches have been tested but no fully approved HIV vaccine exists yet. Several promising approaches are in advanced trials. The most notable developments include virus-like particle (VLP) vaccines, mRNA vaccine platforms, and broadly neutralizing antibody (bNAb)-based strategies, which are in Phase 2/3 trials. 

Numerous factors contribute to the challenges in obtaining an effective HIV vaccine. Lessons from the development of HIV vaccines include that effective vaccines would likely have to stimulate broadly neutralising humoral responses and effective T-cell immunity. Furthermore, certain correlates of protection and loss of protection have been identified.  Insights gained from vaccine trials have advanced the understanding of HIV, as we continue to explore novel approaches in antigen designs, vaccine delivery and combinations of approaches. This chapter summarises the current status of HIV vaccine development and the promising vaccine candidates.

The development of an HIV vaccine is hindered by several key challenges:

  • HIV’s high genetic diversity: HIV exists in a multitude of subtypes (clades) and mutates rapidly within an individual, making it difficult to design a vaccine that can target all variants.
  • Immune evasion: HIV has evolved mechanisms to evade the host immune system, particularly by integrating into host DNA, creating latent reservoirs and hiding critical epitopes on its envelope proteins through extensive glycosylation.
  • Lack of natural immunity: Unlike most viral infections, natural infection with HIV does not confer sterilizing immunity, further complicating efforts to induce protective immunity.

Types of HIV Vaccines Under Investigation

  1. Preventive Vaccines: These aim to prevent HIV infection in HIV-negative individuals and are the primary focus of vaccine development.

  2. Subunit Vaccines: These vaccines use specific HIV proteins (e.g., the gp120 or gp140 envelope glycoproteins) to stimulate the immune system. However, these proteins have proven difficult to target due to their high variability.

  3. Viral Vector Vaccines: Viral vectors (such as adenovirus or canarypox) are used to deliver HIV genes into the body. These vectors prompt the immune system to generate an immune response against the virus. The Step Study (HVTN 502) tested an adenovirus serotype 5-based vaccine, but it showed no protection and actually increased susceptibility to HIV in certain individuals.

  4. mRNA Vaccines: Following the success of COVID-19 mRNA vaccines, this technology is now being explored for HIV. mRNA platforms can potentially generate a stronger and more targeted immune response. Moderna and the NIH Vaccine Research Center are working on mRNA-based HIV vaccine candidates that aim to elicit bNAbs.

  5. Therapeutic Vaccines: These vaccines aim to control viral replication or induce an immune response in people already living with HIV, potentially reducing the need for ART or enabling HIV remission. Therapeutic HIV vaccines typically focus on enhancing the immune response to control viral load in chronically infected individuals, with the hope of eventually achieving a functional cure (i.e., long-term viral suppression without ART).

Broadly Neutralizing Antibodies (bNAbs)

Researchers have isolated bNAbs from the blood of people living with HIV and studied them in an effort to design novel vaccine candidates. The bNAbs are antibodies that can neutralize a wide range of HIV strains, making them a powerful tool in HIV prevention and treatment. Key bNAbs include VRC01, 3BNC117 and 10-1074. VRC01 is a human monoclonal antibody targeting the HIV-1 CD4 binding site. Early-phase clinical trials of VRC01 and 3BNC117 showed reduced viral load in HIV-1-infected individuals not on HAART. HVTN 703 and HVTN 704 trials investigate the effectiveness of VRC01. 

While bNAb-based therapy has shown promise in preventing infection and controlling viral load in HIV-infected individuals, inducing the immune system to produce bNAbs naturally through vaccination remains a major goal. Studies show bNAbs vary in effectiveness depending on regional HIV strains, meaning vaccines may need to be tailored to local viral clades. Efforts are focused on creating sequential immunization strategies to stimulate the production of these antibodies. 

Progress in HIV Vaccine Development in 2025

  • Proof-of-concept achieved: IAVI/Scripps Research bnAb‑Priming Vaccines—two Phase 1 trials (North America and Africa) demonstrated that bNAb germline-targeting vaccines can activate B cells to begin producing bNAbs, a critical step toward a universal HIV vaccine.
  • bNAb strategies are the most promising, aiming for broad protection across HIV’s diverse strains.
  • Stepwise immunization may be the key to overcoming HIV’s complexity and have proven capable of priming bNAbs in humans.
  • mRNA vaccines are now in Phase 2 trials, leveraging rapid design and adaptability to HIV’s mutations.
  • VLP vaccines are progressing, offering safer platforms with strong immune responses.

Table 29.10 Leading HIV Vaccine Candidates

While no HIV vaccine has been licensed yet, significant progress has been made in understanding the complexities of the virus and how to induce immunity against it. The success of the COVID-19 mRNA vaccines has breathed new hope into HIV vaccine research, with mRNA technology being at the forefront of innovative approaches. Continued efforts in bNAb development, VLPs and mRNA vaccine platforms, and global collaboration are paving the way toward the goal of an HIV vaccine. 

References

  1. Gray, G.E., Mngadi, K., Lavreys, L, et al. (2024) Mosaic HIV-1 vaccine regimen in southern African women (Imbokodo/HVTN 705/HPX2008): a randomised, double blind, placebo-controlled, phase 2b trial. Lancet Infect Dis;24:1201-1212. https://doi.org/10.1016/S1473-3099(24)00358-X
  2. Gray, G. E., Laher, F., Lazarus, E., Ensoli, B., & Corey, L. (2016). Approaches to preventative and therapeutic HIV vaccines. Current Opinion in Virology, 17: 104–109. https://doi.org/10.1016/j.coviro.2016.02.010
  3. Hammer, S. M., Sobieszczyk, M. E., Janes, H., Karuna, S. T., Mulligan, M. J., Grove, D., et al.; HVTN 505 Study Team. (2013). Efficacy trial of a DNA/rAd5 HIV-1 preventive vaccine. The New England Journal of Medicine, 369(22): 2083–2092. https://doi.org/10.1056/NEJMoa1310566
  4. Hannah, S., Chinyenze, K., Shattock, R., Yola, N., & Warren, M. (2022). HIV vaccines in 2022: Where to from here? Journal of the International AIDS Society, 25(5), e25923. https://doi.org/10.1002/jia2.25923
  5. Jefferys, R. (2024). The HIV vaccines and passive immunization pipeline report. https://www.treatmentactiongroup.org/wp-content/uploads/2024/07/pipeline_HIV_VAX_2024_final.pdf
  6. Joseph, S., Kaleebu, P., Ruzagira, E., et al. (2019). OC 8491 PREPVACC: A phase III, MAMS adaptive prophylactic HIV vaccine trial with a second randomisation to compare F/TAF with TDF/FTC PrEP. BMJ Global Health, 4, A10. https://doi.org/10.1136/bmjgh-2019-EDC.23?urlappend=%3Futm_source%3Dresearchgate.net%26utm_medium%3Darticle
  7. Kim, J., Vasan, S., Kim, J. H., & Ake, J. A. (2021). Current approaches to HIV vaccine development: A narrative review. Journal of the International AIDS Society, 24(Suppl 7), e25793. https://doi.org/10.1002/jia2.25793
  8. Lynch, R. M., Boritz, E., Coates, E. E., et al. (2015). Virologic effects of broadly neutralizing antibody VRC01 administration during chronic HIV-1 infection. Science Translational Medicine, 7(319), 319ra206. https://doi.org/10.1126/scitranslmed.aad5752
  9. Mahomed, S., Pillay, K., Hassan-Moosa, R., et al. (2025). Clinical trials of broadly neutralizing monoclonal antibodies in people living with HIV: A review. AIDS Research and Therapy, 22, 44. https://doi.org/10.1186/s12981-025-00734-8
  10. Ministry of Health Malaysia. (2023).The Global AIDS Monitoring Report. https://www.moh.gov.my/moh/resources/Penerbitan/Laporan/Umum/Laporan_Global_AIDS_Monitoring_2023.pdf
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