The covid19 vaccine – your questions answered

PDP deputy leader Dr Faith BYisrael. PHOTO COURTESY THA -
PDP deputy leader Dr Faith BYisrael. PHOTO COURTESY THA -

IT is 2021 and unfortunately the world is still in the throes of the covid19 pandemic.

One of the major evolutions though is the development and recent availability of the covid19 vaccine. Several companies embarked on the research and development of the vaccine since the beginning of the pandemic, but only three companies – Pfizer, BioNTech and Moderna, have approved vaccines that are currently being distributed.

Our Minister of Health indicated that the vaccines would be available in Trinidad and Tobago in a couple months. There have been a lot of speculation, suspicion, and questioning about the vaccine, so in this article I will discuss how our immune system works, how vaccines work, and why the covid19 vaccines were created so quickly.

The immune system

The immune system is a network of cells, tissues, and organs that work together to defend the body from harmful germs. When bacteria, viruses, and other germs invade your body, they multiply and attack. This invasion is called an infection. Infections cause the diseases that make you sick.

Your immune system protects you from the disease by fighting off the invading germs. Your immune system is always on patrol in your body. When it comes across an invading germ, it attacks that germ. This is called an immune response.

Here’s how an immune response works:

· Your immune system sounds the alarm so your body knows there’s an infection.

· It begins releasing antibodies to fight the germ — think of antibodies as soldiers designed to fight off the specific germ you have. This process can take a few days.

· The antibodies work to attack, weaken, and destroy the germ.

· Afterwards, your immune system remembers the germ. If the germ invades again, your body can recognise it and quickly send out the right antibodies so you don’t get sick.

· This protection against a certain disease is called immunity. In many cases, immunity lasts your whole life.

What are vaccines?

A vaccine is made from very small amounts of weak or dead germs that can cause diseases — for example, viruses, bacteria, or toxins. It prepares your body to fight the disease faster and more effectively so you won’t get sick.

Vaccination is the act of getting a vaccine, usually as a shot.

Immunization is the process of becoming immune to (protected against) a disease. Immunization can also mean the process of getting vaccinated.

There are now five main types of vaccines:

1. Live-attenuated vaccines

Live vaccines use a weakened (or attenuated) form of the germ that causes a disease. Because these vaccines are so similar to the natural infection that they help prevent, they create a strong and long-lasting immune response. Just one or two doses of most live vaccines can give you a lifetime of protection against a germ and the disease it causes. Examples include yellow fever, chicken pox and measles/mumps/rubella.

2. Inactivated vaccines

Inactivated vaccines use the killed version of the germ that causes a disease. Inactivated vaccines usually don’t provide immunity (protection) that’s as strong as live vaccines, so you may need several doses over time (booster shots) in order to get ongoing immunity against diseases. Examples include the polio, rabies, hepatitis A and flu.

3. Subunit, recombinant, polysaccharide, and conjugate vaccines

Subunit, recombinant, polysaccharide, and conjugate vaccines use specific pieces of the germ — like its protein, sugar, or capsid (a casing around the germ).

Because these vaccines use only specific pieces of the germ, they give a very strong immune response that’s targeted to key parts of the germ. They can also be used on almost everyone who needs them, including people with weakened immune systems and long-term health problems.

One limitation of these vaccines is that you may need booster shots to get ongoing protection against diseases. Examples include hepatitis B, HPV, shingles, and whooping cough.

4. Toxoid vaccines

Toxoid vaccines use a toxin (harmful product) made by the germ that causes a disease. They create immunity to the parts of the germ that cause a disease instead of the germ itself. That means the immune response is targeted to the toxin instead of the whole germ. Like some other types of vaccines, you may need booster shots to get ongoing protection against diseases. Examples include tetanus and diphtheria.

The final, most recent type of vaccine is that of the mRNA category. These will be discussed in detail below.

Trinidad and Tobago vaccine rates

Trinidad and Tobago has one of the most successful immunisation programmes in the world. The programme includes approximately 13 vaccines, including Bacillus Calmette Guerin (BCG), inactivated polio (Pol3), measles (MCV1 & 2), hepatitis B (HepB3) and yellow fever (YFV).

The World Health Organization’s (WHO) 2019 Report indicates that Trinidad and Tobago ranges from 90 per cent to 99 per cent coverage for the various vaccines.

How did they develop the covid19 vaccine so quickly?

The world expressed surprise, excitement, and significant concern at the announcement of several vaccines to help prevent covid19 infections.

These vaccines were created in approximately nine to ten months, while it took several years for previous vaccines to be created.

In this section I discuss mRNA vaccines, the new technology that allowed the relatively swift creation of these covid19 vaccine.

The Centers for Disease Control and Prevention (CDC) said, “mRNA vaccines are a new type of vaccine to protect against infectious diseases.

To trigger an immune response, many vaccines put a weakened or inactivated germ into our bodies. Not mRNA vaccines. Instead, they teach our cells how to make a protein—or even just a piece of a protein—that triggers an immune response inside our bodies. That immune response, which produces antibodies, is what protects us from getting infected if the real virus enters our bodies.

Covid19 mRNA vaccines give instructions for our cells to make a harmless piece of what is called the “spike protein.” The spike protein is found on the surface of the virus that causes covid19.

Covid19 mRNA vaccines are given in the upper arm muscle. Once the instructions (mRNA) are inside the immune cells, the cells use them to make the protein piece. After the protein piece is made, the cell breaks down the instructions and gets rid of them.

Next, the cell displays the protein piece on its surface. Our immune systems recognise that the protein doesn’t belong there and begin building an immune response and making antibodies, like what happens in natural infection against covid19.

At the end of the process, our bodies have learned how to protect against future infection. The benefit of mRNA vaccines, like all vaccines, is those vaccinated gain this protection without ever having to risk the serious consequences of getting sick with covid19.”

Are the vaccines safe? How were they developed so quickly?

While an mRNA vaccine has never been on the market anywhere in the world, mRNA vaccines have been tested in humans before, for at least four infectious diseases: rabies, influenza, cytomegalovirus, and Zika.

To receive approval for use in humans, vaccines must go through a series of safety and effectiveness clinical trials.

This process includes: (1) Pre-clinical analysis in animals, (2) Phase 1 clinical trials in a small number of people, (3) Phase II clinical trials with 100s of people, (4) Phase III clinical trials with 1000s of people, and (5) regulatory review for approval.

This process usually takes several years, but in this case large volumes of vaccines were actually manufactured during the Phase III clinical trial period. This was done because governments contributed to the cost of mass producing these vaccines, which reduced the risk to the drug companies. Therefore, as soon as the regulatory reviews were complete, vaccines were available for distribution.

As we continue to learn about covid19 and the covid19 vaccines, it is my hope that we would all be able to live in a world that has less restrictions. Until then, I am encouraging all of you to continue adhering to the regulations/guidelines – don’t congregate, keep washing your hands, wear your mask, and stay at home (and call 800-HEAL if you have symptoms).

Dr Faith B.Yisrael (formerly Faith Brebnor) is a health educator, social scientist, public health specialist and politician.

E-mail: DrFaith@ImaniConsulting.Org

Phone: 494-8827

Facebook Page: @ImaniConsultingAndFoundationTobago

References:, “Vaccine Basics”:

Trinidad and Tobago: WHO and UNICEF estimates of immunization coverage: 2019 revision:

Centers for Disease Control and Prevention (CDC), “Understanding mRNA covid19 Vaccines”:

MedPageToday, “Want to Know More About mRNA Before Your COVID Jab?”:


"The covid19 vaccine – your questions answered"

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