Vaccine – How well do you know about Covid-19 vaccines?

Vaccine – How well do you know about Covid-19 vaccines?

Jun 9, 2021


The third-round opt-in for AstraZeneca vaccine jab had been launched on 26 May 2021 and it has been the hot rising topic up to this date. What is vaccine? How can vaccines improve our immunity? Before we talk about it, let us understand how our immune system works? One of the ways is by acquired immunity. It occurs throughout our life, especially when our body responses to infection or vaccines against microorganisms.

The vaccine helps to develop acquired immunity by imitating an infection. When responding to it, our immune system will produce white blood cells and antibodies. Once the fake infection goes away, our body is left with a supply of white blood cells that will remember how to fight the disease in the future.

It might take a few weeks for the body to produce white blood cells after vaccination. Thus, if the person is infected with a disease just before or just after vaccination, he/she could develop symptoms and get the disease, because the vaccine has not had enough time to provide protection.

Types of Covid-19 Vaccine in Malaysia

Various Covid-19 vaccines had been introduced in Malaysia. However, their efficacy might vary accordingly to the way clinical studies had been conducted, the risk of disease in volunteers, and many other factors. WHO has prescribed that the minimum level of efficacy should be 50%.

Types of Vaccine mRNA Viral Vector Inactivated Virus
Function Uses the mRNA molecule to stimulate the immunity to recognize the targeted virus protein. A safe viral vector is used to deliver the genetic code of the targeted virus and stimulating the human immune response. A virus that has been killed and used to stimulate the human immune response.
Analogy The thief (coronavirus) has the key (mRNA) to our house (body). Scientists found this key (mRNA) and sent it to the vaccine to teach us to build a fence (immune response) that will protect us from the thief. The betrayer thief (viral vector) betrayed the other thieves (coronavirus) by sending a message to the house (body) to build a fence (immune response) to prevent future thieves from coming. The thief (coronavirus) tries to break into the house & attacks. The thief is being noticed & bring to prison (lab) for investigation. The bad side of the thief is killed and become a good person (inactivated vaccine). The good person builds a fence (immune response) at our house (body) making it stronger to prevent future thieves from coming.
Vaccine candidate Pfizer
  • AstraZeneca
  • CanSino Biologics
  • Sputnik V

From the table, we can see that each type of vaccine works differently from each other. Thus, we could not simply jump to a conclusion that vaccine A is better than vaccine B or C by just referring to the efficacy rate. This is because, the efficacy rate is the result under controlled environment in a clinical trial. What matter the most is the effectiveness or how the vaccine perform in the real world.

Thus, rest assured that all vaccines which had been secured in Malaysia are safe and certified by National Pharmaceutical Regulatory Agency (NPRA). Just like any other medication, the side effects are usually mild and well tolerated.

All these vaccines are nearly 100 percent effective at preventing severe illness and death. The important thing is not the type of vaccine that we get, it is that we get vaccinated to achieve 80% herd immunity. It is one of many steps which we can take to protect ourselves and our family from COVID-19. Protection from COVID-19 is critically important because for some people, Covid-19 can cause severe illness or death.

  1. Jawatankuasa Khas Jaminan Akses Bekalan Vaksin Covid-19 (JKJAV), 2021. What are the types of vaccines? available at
  2. Jawatankuasa Khas Jaminan Akses Bekalan Vaksin Covid-19 (JKJAV), 2021. National Covid-19 Immunisation Programme available at -19_Immunisation_Programme_English.pdf