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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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Available Vaccines

COVID-19

In this chapter:

Introduction

COVID-19 is caused by SARS-CoV-2 virus, a single-stranded RNA virus from the genus Betacoronavirus of the Coronaviridae family. SARS-CoV-2 is primarily spread through respiratory droplets and aerosols and from direct person-person contact. The virus can persist in respiratory secretions for 7-12 days after symptom onset, and viral loads are highest soon after symptom onset.

Common symptoms include headache, fatigue, cough, and muscle aches. Severe cases of the disease can lead to pneumonia, acute respiratory distress syndrome (ARDS), and multi-organ failure. A long-term complication, known as Long COVID, involves symptoms persisting 12 to 16 weeks after the initial infection.

In Malaysia, more than 5 million cases were reported with 37,000 deaths in June 2025.

Table 4.1 Vaccines Registered in Malaysia

In Malaysia, following the transition to endemicity of COVID-19 since January 2023, MySejahtera app has been utilised for healthcare information, infectious diseases tracking, health screening and appointments. The COVID-19 vaccination programme is now available in public health clinics.

Table 4.2 High-Risk Groups in Malaysia

Note:
Any individuals aged 6 months and above who has not been vaccinated before, and who wish to be vaccinated, can receive the up-to-date vaccine.

For COVID-19 vaccine additional dose, any individuals age 18 years and above and who wish to be vaccinated, may receive boosters at intervals of 12 months using the up-to-date vaccine.

Implication for Healthcare Workers (HCWs)

Never received COVID-19 vaccine
One dose of the COVID-19 vaccine is to be given for healthcare workers with direct contact with patients.

Previously received at least one dose of COVID-19 vaccine
An updated booster dose is recommended every 12 months for healthcare workers with direct contact with patients.

Evidence of Safety and Effectiveness

Recent evidence suggests that LP.8.1-adapted COVID-19 vaccines demonstrate improved immunogenicity and clinically meaningful effectiveness against currently circulating SARS-CoV-2 variants, particularly those within the JN.1 lineage.

Clinical data indicate that LP.8.1-adapted mRNA vaccines are associated with increased protection against severe COVID-19 outcomes caused by currently circulating variants. Early effectiveness estimates from the 2025–2026 vaccine formulation report approximately 54–57% protection against hospital visits due to COVID-19 shortly after vaccination, supporting moderate real-world effectiveness in the context of ongoing viral evolution. However, neutralizing antibody titres against heterologous variants may be modestly reduced compared with the homologous strain, highlighting the continued need for periodic vaccine updates.  

COVID-19 vaccines are generally safe and well-tolerated. Adverse events associated with vaccines have been generally rare, and the benefits of vaccination have far outweighed the risks.

With regards to myocarditis occurring one week after the second dose of mRNA vaccine, the overall incidence is very low – typically 0.3-1.9 cases per 100,000 doses in young adults, especially among males under 30 years old. Most of the cases are mild with symptoms of chest discomfort, followed by full recovery.

References

  1. Link-Gelles, R., Chickery, S., Webber, A,. et al. Interim Estimates of 2024–2025 COVID-19 Vaccine Effectiveness Among Adults Aged ≥18 Years — VISION and IVY Networks, September 2024–January 2025. (2025). MMWR Morb Mortal Wkly Rep, 74:73–82. http://dx.doi.org/10.15585/mmwr.mm7406a1
  2. World Health Organization. (19 July 2023). Interim recommendations for the use of mRNA COVID-19 vaccines. https://www.who.int/publications/i/item/WHO-2019-nCoV-vaccines-SAGE-recommendation-mRNA-2023.1
  3. Witberg, G., Barda, N., Hoss, S., et al. (2021). Myocarditis after Covid-19 Vaccination in a Large Health Care Organization. The New England Journal of Medicine, 385(23), 2132–2139. https://doi.org/10.1056/NEJMoa2110737
  4. Guo, B. Q., Li, H. B., & Yang, L. Q. (2023). Incidence of myopericarditis after mRNA COVID-19 vaccination: A meta-analysis with focus on adolescents aged 12-17 years. Vaccine, 41(28), 4067–4080. https://doi.org/10.1016/j.vaccine.2023.05.049
  5. World Health Organization. (October 8, 2024). WHO advice for the public on COVID-19 vaccines. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/covid-19-vaccines/advice
  6. Centers for Disease Control and Prevention. (November 4, 2025). Routine COVID-19 vaccination guidance. https://www.cdc.gov/covid/hcp/vaccine-considerations/routine-guidance.html
  7. Centers for Disease Control and Prevention. (November 4, 2025). COVID-19 Vaccination Guidance for People Who Are Immunocompromised. https://www.cdc.gov/covid/vaccines/immunocompromised-people.html
  8. Appaneal, H. J. (2026). Early effectiveness of the BNT162b2 LP.8.1 vaccine against COVID-19 emergency department, urgent care, and outpatient visits in the US Veterans Affairs. medRxiv. https://doi.org/10.64898/2026.01.22.26344618
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