SARS-CoV-2, the virus that causes Coronavirus disease-19 (COVID-19), has rapidly spread around the globe. Caused one of the biggest pandemic ever witnessed in the world. It led to death of about 2 million people and researchers have worked round the clock to give the world vaccines effective against Coronavirus.
WHICH VACCINES HAVE BEEN APPROVED?
Diverse vaccines are available in different countries.
- The Pfizer-BioNTech vaccine, developed in Germany, received FDA approval in the form of an emergency use authorization on 11th of December 2020.
- The Moderna vaccine, developed in Cambridge, MA, received approval for emergency use in the U.S. In a phase 3 trial, 30,000 volunteers received either a placebo or two doses of the vaccine, 28 days apart. The vaccine is about 94% effective.
- COVAXIN, India's indigenous COVID-19 vaccine by Bharat Biotech is developed in collaboration with the Indian Council of Medical Research (ICMR) - National Institute of Virology (NIV). The indigenous, inactivated vaccine is developed and manufactured in Bharat Biotech's BSL-3 (Bio-Safety Level 3) high containment facility.
- The Oxford-AstraZeneca vaccine is being manufactured locally by the Serum Institute of India, the world's largest vaccine manufacturer. It says it is producing more than 50 million doses a month. The vaccine is made from a weakened version of a common cold virus (known as an adenovirus) from chimpanzees. It has been modified to look more like coronavirus - although it can't cause illness.
Other vaccines that have approval for use in various countries include:
- The Oxford AstraZeneca vaccine, in the United Kingdom
- Coronavac, developed by Sinovac, in China
- The Sputnik V vaccine, in Russia
- Covaxin, developed by Bharat Biotech, in India
ARE THERE ANY SIDE EFFECT OF THIS VACCINE?
The safety of each coronavirus vaccine is tested in pre-clinical and clinical trials. The most common side effects of coronavirus vaccines are as follows:
- pain at the injection site
- tiredness or fatigue
- muscle pain
- joint pain
- swelling or redness at the injection site
- feeling unwell
- swollen lymph nodes (lymphadenopathy)
These side effects last for an average of 1 to 2 days. Most people have mild or moderate symptoms, while for some people symptoms may be more severe.
Types of COVID-19 vaccine
Researchers have used various approaches to developing vaccines that protect against COVID 19. As a result, they have developed different types of vaccine, including:
- whole virus vaccines
- recombinant protein subunit vaccines
- replication-incompetent vector vaccines
- nucleic acid vaccines
We explore these types in more detail below:
Whole virus vaccine
Also known as an “inactivated” or “weakened” virus vaccine, this type contains dead or inactivated forms of the virus.
These vaccines cannot cause an infection because they do not contain the live virus.
The COVID-19 vaccines made by Sinovac, Bharat Biotec, and the Wuhan Institute of Biological Products belong to this category of vaccines.
Recombinant protein subunit vaccine
This type of vaccine causes a strong immune response to a key part of the virus. It cannot cause an infection because it does not contain a live pathogen, such as a virus.
Researchers are investigating whether they can make a recombinant protein subunit vaccine that focuses on a protein, called the spike protein, that the new coronavirus uses to latch onto and infect cells.
Novavax, using nanoparticle technology is developing a vaccine.
Replication-incompetent vector vaccine
This type acts as a platform for carrying genes that the body can express to provide immunity.
The AstraZeneca vaccine, which has approval in some countries, is a replication-incompetent vector vaccine. It makes use of weakened adenovirus that causes the common cold in chimpanzees to provoke an immune response.
The scientists then changed the virus to make it suitable for use in humans. In other vaccines, this type of virus has safely produced a strong immune response.
Ebola vaccine of this type received approval, and it may provide the basis for further COVID-19 vaccines.
Nucleic acid vaccine
This type is also called an mRNA-based vaccine. Vaccination involves injecting genetic material called mRNA into live host cells.
Each of these vaccines is designed to target a particular pathogen. In a COVID-19 vaccine, the mRNA contains instructions for producing coronavirus spike protein. The vaccine presents this information to the immune system, and as a result, the body produces antibodies to combat the virus.
Pfizer, BioNTech, and Moderna have developed Nucleic acid vaccines. The Pfizer-BioNTech and Moderna vaccines are already available in the U.S.
How do vaccines work?
Vaccines trigger the immune system to make antibodies to defend against specific diseases. In other words — they make the immune system behave as if the body already had this illness.
Vaccines achieve this without making the person sick.
After vaccination, the person develops immunity to the disease. Their body can fight off the infection if exposure to the pathogen, such as the novel coronavirus, occurs.
An effective vaccine stimulates the immune system without kicking it into overdrive. Developing a vaccine that works without causing unwanted side effects is the goal for researchers.
Vaccines also need to be safe for everyone, including people with allergies, young children, people who are pregnant or breastfeeding, older adults, and people with underlying health conditions.
Should pregnant or breastfeeding women get the vaccine?
Many vaccines are safe for pregnant or breastfeeding women.
However, pregnant women were not included in either the Pfizer-BioNTech or Moderna coronavirus vaccine clinical trials.
So we cannot know for certain how well the vaccine will work in this group or if there will be side effects not seen in people who participated in the earlier phase 3 clinical trials.
Can immunocompromised people get vaccinated?
Pfizer included some people with stable HIV infection in its phase 2/3 clinical trial, but the data from that subgroup is not yet available.
People who are immunocompromised can get the coronavirus vaccine if they have no other condition that would preclude them from receiving the vaccine.
However, because scientists don’t yet know how well the vaccine works in people with weakened immune systems, they should still take steps to protect themselves from coronavirus infection.
Ways of reducing the risk of infection:
- wearing a face covering in public
- washing the hands with soap and hot water frequently, for at least 20 seconds at a time
- using a hand sanitizer, with at least 60% alcohol, when washing the hands is not possible
- covering any sneeze or cough with a tissue, disposing of this at once, and washing the hands
- avoiding touching the face
- regularly cleaning and disinfecting surfaces that people frequently touch, such as doorknobs
- limiting or avoiding handshakes
- staying home and away from others if sick
- staying at least 6 feet away from people who are not housemates
- avoiding crowds whenever possible
- avoiding poorly ventilated places whenever possible
- being watchful for any symptoms, including a high fever and a cough
If a person has a mild or asymptomatic form of COVID-19, it is still crucial that they limit their contact with others, especially older adults and people with weakened immune systems.
COVID-19 is a major health challenge throughout the world. Experts and authorities are working to develop and administer vaccines and enact other preventive measures.
The goal is for everyone to have access to a COVID-19 vaccine. While waiting for it to become available, follow all guidance from public health authorities and medical experts.