All you need to know about COVID vaccines

The largest vaccination program in the history of the world is well under way. More than 3 crore doses of COVID vaccines have already been administered. Safety concerns and anti-vaccination fear mongering, that had peaked in the past few weeks, are slowly dying down as barely a handful of people have suffered serious adverse effects out of crores who have received the vaccine.

This is the first time in history that an audacious global attempt is being made to stop a raging pandemic in its tracks by mass vaccination, and all indications are that it will be successful. On this very positive note, let us look at some basic facts about vaccination.

Concept

Develop immunity against the disease without actually getting the disease.

How do vaccines make this happen?

By exposing the body to either a live virus that has been greatly weakened, or a dead virus, or parts of the viral DNA/RNA or covering. The body recognises the intruder and destroys it, keeping a copy of it for future reference. If the real virus were to thereafter enter the body, it is already prepared with its defence and eliminates the virus rapidly. Immunity is a complex phenomenon involving various strategies. Antibodies (proteins secreted by the body that attack the invading “antigen”) and certain types of white blood cells (“memory” T-lymphocytes) are two of the key players that help the body clear the invaders before they cause the disease.

Vaccination in ancient times

Ancient Indians and Chinese were pioneers in vaccination. They preserved old scabs from patients who had survived smallpox and specially processed them to expose the population to the weakened virus, thereby imparting immunity with a remarkable success rate of 90%. The simplest method was to tie the scabs in a cloth and hang it in the public area. Another method adopted by the ancients was inoculation, which is similar to an intradermal injection administered in modern days. This technique was called variolation, and when implemented in Europe in the 18th century, it brought mortality from smallpox down from 30% to under 2%.

The 19th and 20th centuries brought about a revolution, as several common childhood diseases such as measles, chicken pox, mumps, rubella, pertussis, diphtheria, tetanus, influenza etc became preventable by vaccination. Smallpox was wiped out from the face of the earth and poliomyelitis is close to being extinguished. Several countries declared themselves free of the abovenamed childhood diseases after intensive programs.

From the primitive techniques of the ancients to the refined highly targeted, tested and researched mass manufacturing of modern vaccines, the purpose of vaccination remains unchanged: prevent the disease before it occurs.

Types of vaccines against COVID

Live attenuated vaccines (Codagenix): The virus is weakened by serial replication through millions of cycles and then introduced into the body via a harmless adenovirus vector. None of the currently licensed vaccines are in this category although some are in advanced trials.

Killed / inactivated vaccines: whole inactivated (Covaxin) / fragmented (Novavax/Dynavax) – the virus is inactivated by certain processes and rendered incapable of replication or causing disease. Thereafter, either the entire inactivated virus or fragments of it are introduced into the body via a harmless viral vector. Of these, Covaxin has been authorised for emergency use in India.

mRNA vaccines (Pfizer / Moderna): This is a radically different technology in which the vector introduces a strand of messenger RNA that instructs the cellular protein synthesis mechanism to secrete a protein identical to the spike protein of SARS-COV2 virus. The mRNA disappears thereafter. The body recognises the spike protein as a foreign agent and destroys it, producing antibodies and memory T-cells. Both Pfizer and Moderna vaccines have completed phase 3 trials and over two crore doses have been administered in several countries across the world.

Plasmid DNA vaccines (ZyCOV-D/Johnson & Johnson): This differs from mRNA vaccines as the vector introduces an inactivated double-stranded DNA instead of a messenger RNA. It is currently in phase 2 trials.

Non-Replicating Viral Vector (Covishield/Cansino/Janssen): Of these, the Covishield (AstraZeneca / Oxford / Serum Institute) vaccine has received emergency use approval in UK and Bharat and mass vaccinations are currently under way.

Replicating Viral Vector (Pasteur/Merck): none of the vaccines of this type have received approval, most of them are in phase 1 trials.

Virus-like Particle (Spybiotech-SII/Max Planck Institute): none of the vaccines of this type have received approval, most of them are in phase 1 trials.

At last count, more than 300 different COVID vaccines are under various stages of development and trials.

How did vaccine companies make the vaccines so quickly?

The answer is quite simple: the structures of different families of viruses, such as rhinovirus, enterovirus, coronavirus etc, are well known. Individual viruses from the respective families have basically similar structure with minor differences. As basic vaccine structures against the overall groups are already in existence, only minor modifications are needed to make it specific to the concerned strain against which protection is needed. In fact, scientists at Moderna prepared the structure of the COVID vaccine over just one weekend in January 2020, even before the pandemic actually broke out. This is an indication of how far the science has advanced.

Whereas the fastest vaccine developed several years earlier took four years to be approved for use, with the massive advances in technology and the wealth of knowledge regarding viruses that is presently available, it need not take years to produce a safe and effective vaccine.

Have trials been bypassed by Bharat’s Govt. in a hurry to give vaccines to everyone?

No. Phase 3 trials of both Covishield and Covaxin have been concluded, with just under 24000 receiving Covishield globally and nearly 26000 receiving Covaxin in Bharat. Data pertaining to the safety and efficacy have been shared with a high-powered governmental body comprising senior researchers and scientists, who have carefully evaluated the information in all respects before giving emergency use approval for both the vaccines.

Why do we still need to wear a mask and maintain distancing after vaccination?

As immunity kicks in two to three months after completing both doses of vaccination, one must continue wearing masks and maintain social distancing for up to three months after receiving the vaccine. Presently, it is not clear as of now whether people who have been given the vaccine and are now immune to COVID19 would still be capable of acting as carriers for infecting others. In a few months, this would become immaterial as the majority of population receives the vaccine and gains immunity.

Why not opt for herd immunity?

Because the cost of human life and suffering needed to produce herd immunity makes it a highly unattractive proposition. For gaining this kind of protection, at least 90% of the population needs to be exposed to the virus. The UK, which had in its early days pursued this policy, quickly took a turnaround on realising the high human cost they would have to pay.

COVID 19 is a disease with an unpredictable course: the bulk of patients would have minimal or no symptoms, but about 20% of patients will need hospitalization, about 5% need intensive care and 1.5-2% of patients will succumb to the disease. It may not sound like a large number, but consider that the population of India is 140 crores. 2% of this translates to close to three million deaths and ten million in intensive care. No government can ever agree to sit back and let this happen. Hence, mass vaccination is the only solution to bring this pandemic to a halt. Thankfully, governments around the world have taken this up.

Will the vaccines work against the new variants?

All indications are that the vaccines will be effective against the new variants also, as the mutations are not significant enough to alter the immune response. Certain vaccines such as Covaxin, being entire virion vaccines, have claimed an added advantage of being unaffected by mutations. The claim seems scientifically valid but has not been proven as of now.

Trust the science

As Bharat rolls out its vaccination program from 16th January 2021, which will be the largest and probably best organised in the world, we should expect the naysayers to scream even more loudly and highlight every rare case of suspected adverse reaction as the norm. Signs of things to come are already visible as some journalists are trying to pass off deaths due to suspected poisoning as related to vaccination.

Lack of proper knowledge combined with a sustained misinformation campaign by vested interests led by a disgraced doctor and dozens of vaccine injury lawyers have created completely unjustified misgivings regarding vaccines. Due to this, the number of completely vaccinated children in the US and UK fell sharply, resulting in outbreaks of completely preventable diseases such as measles, chickenpox, diphtheria and pertussis. These outbreaks are threatening to undo five decades of hard work.

Vaccines have been around since ancient times. They have been proven time and again to be safe and effective. Scientists and researchers across the world over two centuries have dedicated their lives to develop this technology to the point that we no longer need to wait for several years for protection against serious outbreaks of disease. We would do very well to ignore the naysayers and trust the scientists and science. Its time to step forward confidently and take the COVID19 vaccine whenever it is available to the public at large.

Recommended Reading:

  1. History of Vaccines: https://www.historyofvaccines.org/timeline/all
  2. COVID Vaccines in Bharat: https://vaccine.icmr.org.in/covid-19-vaccine
  3. COVID Vaccine Tracker – Global Distribution of Vaccines: https://www.bloomberg.com/graphics/covid-vaccine-tracker-global-distribution/
  4. Details of Novavax: https://www.nytimes.com/interactive/2020/health/novavax-covid-19-vaccine.html
  5. Johnson & Johnson COVID 19 Vaccine: https://www.nytimes.com/interactive/2020/health/johnson-johnson-covid-19-vaccine.html
  6. A comprehensive site for tracking current status of vaccines and treatments for COVID19: https://covid-19tracker.milkeninstitute.org/
  7. We Had The Vaccine The Whole Time: https://nymag.com/intelligencer/2020/12/moderna-covid-19-vaccine-design.html
  8. Man dies in Bhopal days after participating in COVID vaccine trial: https://www.newindianexpress.com/thesundaystandard/2021/jan/09/man-dies-in-bhopal-days-after-participating-in-covid-vaccine-trial-police-begins-probe-2247850.html
  9. Autism’s false prophets, by Paul Offit MD
  10. The Doctor Who Fooled The World: Andrew Wakefield’s War on Vaccines, by Brian Deer

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About the Author

Dr. Amit Thadani
MBBS MS FMAS, Practising surgeon, musician, social activist, amateur photographer. Consulting General & Laparoscopic Surgeon Director, Niramaya Hospital, Kharghar, Navi Mumbai Consultant, Sushrut Hospital & Research Center, Mumbai Consultant, Apollo Spectra Hospital, Mumbai