COVID 19 Vaccine

In 2019, an unknown virus started causing flu-like symptoms in humans and no one knew what to expect out of it. Now, we find ourselves amidst a pandemic with over 95 million people infected with SARS-CoV-2 and more than two million reported deaths. This pandemic has definitely changed our lives drastically and we are all hoping for the pandemic to end so that we can to go back to our normal lives. To overcome the pandemic, we need to achieve herd immunity which can be done by vaccinating. There are many vaccines which are there in the market currently and many which are yet to come, however, I will be covering two most popular vaccines in terms of authorization across many countries: Pfizer BioNTech and Moderna. Before I get into the details of the vaccines, let us first understand the types of vaccines and how they work. A vaccine works by training the immune system to recognize and combat pathogens. This is done by introducing certain molecules called antigens from the pathogen into the body to trigger an immune response. If the pathogen enters the body, the immune system will recognize the antigens and attack the pathogen before it can spread and cause you to be sick. There are 4 main types of vaccines:·

Inactivated vaccines:

• These vaccines use a dead version form of the germ that causes the disease.
• They don’t provide immunity for very long, hence several doses over time (booster shot) are administered.
• Inactivated vaccines are used to protect against diseases such as Flu, Polio, Rabies and Hepatitis A.

Live-attenuated vaccines:

• These vaccines use a weakened (attenuated) form of the germ that causes the disease. They create a long-lasting immune response since they are very similar to the natural infection.
• Live vaccines are used to protect against diseases such as Smallpox, Chickenpox, Yellow fever, Rotavirus and Measles, Mumps, Rubella (MMR).

Toxoid vaccines:

• These vaccines use a toxin created by the disease-causing germ to create immunity to the part of the germ that causes the disease rather than the germ itself.
• This type of vaccine also requires booster shots to get ongoing immunity to diseases.
• Toxoid vaccines are used to protects against diseases such as Tetanus and Diphtheria.

Subunit, recombinant, polysaccharide, and conjugate vaccines:

• These vaccines use specific pieces of the germ such as their sugar, protein or capsid.
• They give a strong immune response since only specific pieces of the germ is used but it also requires booster shots to get ongoing immunity to diseases.
• A major advantage of this vaccine is that it can be given to anyone, including those with a weaker immune system or long-term health issues.
• Subunit, recombinant, polysaccharide, and conjugate vaccines are used to protect against diseases such as Shingles, Hepatitis B and Whooping cough.

The Pfizer BioNTech and Moderna vaccines are both messenger RNA (mRNA) vaccines. This means that the vaccine will give “instructions” which is a piece of RNA which is the genetic code our body needs for our cells to make a harmless piece of the spike protein which is found on the surface of the virus that causes COVID-19.

Once the mRNA is inside the immune cells and the spike protein is created, the spike protein appears on the surface of the cell and the instructions are destroyed. Our immune system then recognizes a pathogen (the spike protein) on the cell and starts making antibodies to fight the pathogen. This whole process takes about 1-2 weeks. 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 COVID-19.

Pfizer BioNTech is manufactured by Pfizer, Inc., and BioNTech. There are two 2 doses of this vaccine. The second dose will be given 21 days after the first dose. Moderna is manufactured by ModernaTX, Inc. There are 2 doses of this vaccine which are 28 days apart.

They have similar side effects. They include:·

• Pain, swelling or redness in the arm around the area of the shot.
• Chills
• Tiredness
• Headache

Vaccine efficacy

In phase three of the clinical trials which had about 44,000 people for the Pfizer BioNTech trial and about 30,400 for the Moderna trial, it was found that they were very efficacious. The Pfizer BioNTech vaccine had an efficacy of 95% which was measured after seven days after the second dose was administered. The Moderna vaccine had an efficacy of 94.1% which was measured after 14 days after the administration of the second dose.

It was found that there was a lower efficacy in people who were 65 and above. A possible explanation could be that there were a few cases in that age group during the trial. It can be deduced that both the vaccines reduced the risk of a severe COVID-19 case across different ethnic and racial groups equally. However, researchers are not able to figure out yet if the vaccines prevent an asymptomatic infection.

Development speed

On an average, it takes 10 years to develop a vaccine. The COVID-19 vaccine took 10 months! This piece of information can be very unsettling. Well, 10 years is a very long time to develop a vaccine and according to experts, it is not required either. The development of the COVID-19 vaccines in 10 months is proof of how much can be done with international collaboration and enough funding.

Though this is a new virus, the researchers have been working on such a scenario for years. For example, University of Oxford has been working on a vaccine for disease X which would be a brand new virus so that when a similar situation arises, they would be able to speed up the process of making a vaccine.

It would be an understatement to say that the past year has been a year of difficulties considering the devastating impact this pandemic has had on the lives of people. The words of one of the world leaders while announcing the commencement of the inoculation drive in his country, ‘many people didn’t reach home…’ simply highlights the impact this pandemic has had on people. With the vaccines that are already developed and those that are being developed, we not only hope that we will be free from the devastating impact of this pandemic sooner than later but also hope that we will be able to prevent the occurrence of such pandemics in the future.