COVID-19 Booster Shot Combination in Malaysia

COVID-19 Vaccines and Booster Shots: Which Combination is Most Effective?

Is it safe to mix and match your COVID-19 vaccines and booster shots and which combination will induce a better immune response?

by Homage team

In the past two years living with COVID-19, numerous measures have been taken to defend against the virus, and the COVID-19 vaccines are one of them. The Malaysian government has been rolling out its vaccination campaign, providing free vaccination shots to residents. Locally, the vaccines available under the national programme are Pfizer-BioNTech/Comirnaty, AstraZeneca and Sinovac-CoronaVac COVID-19 vaccines. Now, the vaccination programme includes the addition of a booster shot. Now that booster shots are available, some of you may be considering whether to take the plunge and take the shot – but questions abound. Who is suitable? Should I take the shot? And more importantly, can I mix and match my vaccines? 

We find out more about booster shots and see which combinations are the most helpful, especially for those who have taken their primary vaccination shots from the national programme.

Why do I need to take the booster shot?

After taking the initial doses of vaccination, their effectiveness starts to wane over time. This is when a booster shot comes into play.

A booster shot is an additional dose of a vaccine given, after the protection of the original shot(s) begins to decrease. It helps people maintain immunity longer against specific diseases or illnesses the vaccine is protecting against. In this case, the booster shot would protect against COVID-19 and the risk of severe infection or complications if contracted.

Booster shots would also help with reducing transmission rates in the community, as more individuals are protected and vaccinated against COVID-19. The Ministry of Health (MOH) shares that vaccine protection from the first two vaccination doses decreases over time –  people vaccinated only with the first two doses may incur a 40% risk for infection with COVID-19, and 90% risk for a severe infection as time passes. This calls for the need to consider a booster shot, which can help to lower the risk of infection. Taking a booster means you are 70% less likely to be infected, and 90% less likely to get symptoms and severe infections from COVID-19, the MOH states. 

Am I eligible to take the booster shot and how do I make an appointment?

Under the National Vaccination Programme, those who are eligible for the booster shot are individuals who are above the age of 18 years and have taken their primary shots about three months ago. 

If you are eligible for a booster dose, an appointment will be set up through the MySejahtera app. 

When should I take the booster shot?

Depending on the vaccines you took, here is the recommended timeline to take your booster shot:

  • Pfizer-BioNTech / Comirnaty, Sinovac, AstraZeneca: Three months after your second dose
  • Johnson & Johnson: Two months after your third dose

Should I take the booster shot if…

I am immunocompromised? 

An immunocompromised person refers to someone whose immune system does not work as well as it should to protect from infections. This makes them more vulnerable to infections and diseases. Immunocompromised people usually are those who have a genetic mutation or a disease like Human Immunodeficiency Virus (HIV), where their condition causes a specific loss of immune function; and those who are taking certain medications to treat specific diseases. For immunocompromised people, Amesh A. Adalja, a senior scholar with the John Hopkins Center for Health Security in the United States, explains that immunocompromised people are less likely to respond to standard vaccination regimens, and hence would benefit from an additional mRNA vaccine dose to be given to them in addition to the primary doses. 

So yes, if you are immunocompromised, you can still take the booster shot. 

I am a senior? 

Data from MOH has shown that seniors unvaccinated against COVID-19 hold a higher risk of a serious outcome from contracting the illness. The data shows that for seniors in their 80s, one in two unvaccinated seniors, versus one in eight vaccinated seniors, will require intensive care, oxygen, or succumb to COVID-19. Taking the vaccination would markedly lessen the risk of severe consequences of COVID-19 for seniors. Knowing that vaccination efficiency wanes over time, it is hence important that seniors get the booster shot as well. Booster shots are also available to seniors. 

I am under 18 years old?

Currently, individuals under the age of 18 years are not eligible to take a booster dose. 

However, individuals between the age of five to 17 years are now eligible for vaccination. Under the Ministry of Health (MOH), vaccination for those between 5 to 11 years of age will begin by the end of January.

I have had COVID-19? 

If you were fully vaccinated before being infected with COVID-19, currently, you would not need a booster dose. However, people who were partially vaccinated or unvaccinated before their COVID-19 infection should receive a dose of mRNA vaccine at least three months after their infection. This helps to reduce their risk of reinfection, and also complete their primary series of vaccination. No booster dose is indicated for this population presently.

Care Professionals That You Trust

 Homage Care Professionals are carefully selected with your safety and well-being in mind. Our professionally trained nurses and caregivers go through a rigorous screening process, and are selected to care for you and your loved ones based on your needs. 

Want to find out more about our Care Professionals? Simply reach out to us by filling out this form!

Will I get any symptoms from the booster shot?

Like other vaccines, you may experience some side effects from the booster shot. Most side effects are mild or moderate, and get better within a few days. Some common side effects include:

  • Pain
  • Redness
  • Swelling at the injection site
  • Fever
  • Chills
  • Headache
  • Muscle pain
  • Joint pain
  • Tiredness
  • Lymph node swelling at neck or arms

These are easily treated with rest, and by giving some time for the symptoms to fade. Paracetamol can be taken for pain, fever, chill, and headaches as well. However, do observe and see a doctor if: 

  • The side effects persist or get worse
  • The fever persists for more than 48 hours (2 days)
  • Respiratory symptoms such as cough, runny nose, sore throat, shortness of breath or loss of sense of taste and smell develop
  • Heart or chest symptoms such as chest pain, shortness of breath or abnormal heartbeats develop

Very rarely, someone may have a severe allergic reaction to the vaccine, which may appear as difficulties with breathing, swelling of the face, throat, eyes, or lips, a fast heartbeat, dizziness and weakness, and rashes all over the body. Should there be any of such signs observed, do call 999 or go to the nearest A&E immediately. 

Will the booster shot protect me from the Omicron?

A study from Pfizer-BioNTech noted that individuals who have received a third dose of the Pfizer vaccine appeared to have better defence against the Omicron variant, as compared to individuals who only had two shots of the vaccine. It has also been reported that a third dose of the AstraZeneca vaccine appears to provide significant protection against the Omicron variant. From the report, the authorised booster is reportedly able to “boost neutralising antibody levels (offer protection against COVID-19) 37-fold higher than pre-boost levels.”

However, at present, there is insufficient data to conclude vaccination effectiveness against the Omicron variant. It is a considerably new variant of the virus, and time is needed for studies to be done to uncover the effectiveness of booster shots on this variant. What is known is that an accelerated response towards vaccination should continue to be the focus of a public pandemic response to encourage widespread immunity. Danny Altmann, an immunologist at Imperial College London, notes that increasing antibody levels with booster shots should help protect against Omicron, just as boosters have improved protection against the Delta COVID-19 variant. So, go ahead to get your booster shots for a better safeguard against Omicron. 

What are the different combinations and which is the most effective?

In line with the local National Vaccination Programme, the booster shots can be ‘mixed and matched’ according to your choice. That means if you had Pfizer vaccination shots for your first two jabs, you can opt for an authorised and permitted alternative. What is the logic behind mixing and matching vaccines? According to Universiti Malaya epidemiologist Professor Datuk Dr Awang Bulgiba Awang Mahmud, several studies have shown that mixing vaccines with an mRNA vaccine is highly effective in strengthening immunity.

Here are explanations for some terms used in the below comparisons:

  • International Units Per Millilitre: An international unit is an amount of a substance agreed upon by scientists and doctors. 
  • Neutralising antibodies: An antibody that is responsible for defending cells from organisms that cause disease. They can be triggered by infections or by vaccines. 
  • Binding Antibody Units Per Millilitre: Unit of measurement determined by the World Health Organisation (WHO) to measure the amount of anti-COVID-19 immunoglobulin. 



Studies have found that this combination allowed for a 62% reduction of infection risk upon getting the booster. There were also 446.7 international units per ml of neutralising antibodies, and 3409.1 binding antibody units per ml. 


For individuals who are thinking of taking AstraZeneca as a booster shot on top of their Pfizer vaccinations, a UK study showed that the antibodies increased and provided protection against COVID-19. 



The AstraZeneca-only route shows to have 901.8 international units per millilitre of neutralising antibodies, and 6799.8 binding antibody units per millilitre.


According to current studies, taking the Pfizer vaccine as a booster on top of the AstraZeneca vaccines provides the largest boost in terms of antibodies through its mRNA technology.


For Sinovac, the MOH mandated that to be considered as a fully vaccinated individual, two doses of the Sinovac vaccine and a booster shot must be administered before February 2022. The recommended booster shot is the mRNA vaccine available which is Pfizer.


Currently, there is little research on this combination. A study from the Chile Health Ministry that this combination increased vaccine effectiveness to 95% from 54%. However, a research study from Turkey has suggested that people fully immunised with Sinovac may have greater protection from taking a booster shot of Pfizer. The study compared groups of healthcare workers who took different vaccine combinations and found that health care workers who received a booster shot of the Pfizer vaccine, versus those who took the third dose of Sinovac, were found to have higher antibody levels which is thought to be a marker of vaccine efficacy. Moreover, for the former combination, there was a smaller percentage of healthcare workers infected with COVID-19 than those who received the Sinovac.  However, more research is to be done in the Sinovac-Pfizer combination for conclusive results. 


Like the above combination, little research has been done on the Sinovac-AstraZeneca combination. The same Chilean study concluded that a Sinovac and AstraZeneca combination increase vaccine effectiveness to 94% from 54%.

With the many vaccination combinations available, what we know is one thing for sure: getting a booster shot will help to increase your protection against COVID-19. As the COVID-19 situation unfolds rapidly, with various new variants in a short span of two years, perhaps the safest thing to do is to get a booster shot regardless.

Key Takeaways

Despite the existence of different vaccines against COVID-19, our safety is still uncertain. Thus, following proper precautionary measures is also one of the best way to protect ourselves from the threat of the virus. Also, if you are not sure on what vaccine to use or mix, you can always consult a doctor to address any concerns you have.

Aside from that, Homage provides caregiving services for your loved ones at every stage. Our trained care professionals are able to provide companionship, nursing care, night caregiving, home therapy and more, to keep your loved ones active and engaged. 

Provide the best care to your loved one today! Fill up the form below for a free consultation with our Care Advisory team. 

  1. Booster Shots, Third Doses and Additional Doses for COVID-19 Vaccines: What You Need to Know. (n.d.). Johns Hopkins Medicine.
  2. Colby, C. (2021, December 26). Moderna booster update: How well and how long does it protect against omicron? CNET.
  3. Healio. (n.d.). Will immunocompromised patients need a COVID-19 vaccine booster every 6 months forever?
  4. Healthwise staff. (n.d.). International units per millilitre (IU/mL). MyHealth.Alberta.Ca.
  5. MacMillan, C. (2021, October 28). What Does It Mean To Be ‘Immunocompromised’? Yale Medicine.
  6. McCarthy, S. (2021, October 2). Coronavirus: Pfizer booster may better protect than third CoronaVac shot, finds Turkish study. South China Morning Post.
  7. Nature Editorial. (2021, December 8). Omicron likely to weaken COVID vaccine protection. Nature.
  8. Quach, J. (2021, March 15). Quantifying antibodies made in response to SARS-CoV-2 vaccination: comparable outcomes from five commercial assays. COVID-19 Immunity Task Force.
  9. Turak, N. (2021, December 21). Moderna says Covid booster appears to protect against omicron. CNBC.
  10. Zoppi, B. L. A. (2021, March 11). What are Neutralizing Antibodies? News-Medical.Net.
About the Writer
Homage team
Make Home Care Personal To Your Loved One

Make Home Care Personal To Your Loved One

Get started with a free consultation today, and learn why thousands of Malaysians trust Homage to deliver the best care in their homes.

Get Care Now