December , 2020
World starts campaign against Covid-19 with Pfizer- BioNTech’s vaccine
11:19 am

Tushar K. Mahanti

The Covid-19 vaccine has finally arrived. And the world is about to see how effective it is. The UK has already given Pfizer and its partner BioNTech’s Covid-19 vaccine a green light and the first doses were given on December 8. A critical meeting among Food and Drug Administration (FDA) advisers slated to give an emergency authorisation in the United States and certain high-risk Americans could begin receiving the vaccines within weeks.

It’s a matter of time for India to begin its vaccination process. First the US pharmaceutical giant Pfizer Inc and then the Serum Institute of India, partnered with AstraZeneca have sought the government’s approval to conduct trials for its Covishield vaccine. Serum Institute of India, the world's largest vaccine maker by number of doses produced has sought the Drug Controller General of India’s (DCGI) approval for emergency use authorisation of the coronavirus vaccine that it is developing with the University of Oxford and British drugmaker AstraZeneca.

The phase-three clinical trial of Covishield, co-sponsored by Indian Council of Medical Research (ICMR), is being conducted in various parts of the country in addition to clinical studies being carried out by Oxford-AstraZeneca in the UK and Brazil. Serum has shared interim data with the DCGI of four clinical trials - one in India, two trials in the UK and one in Brazil.

Serum has claimed that data from four clinical studies shows that Covishield is highly efficacious against symptomatic and most importantly, against severe Covid-19 infections. According to the ICMR, the SII has already manufactured 40 million doses of the vaccine under the at-risk manufacturing and stockpiling license it obtained from the DCGI.

After Pfizer and Serum Institute, Hyderabad-based pharmaceutical firm Bharat Biotech has applied to the central drug regulator on December 7 seeking emergency use authorisation for its Covid-19 vaccine Covaxin.

Covaxin is being indigenously developed by Bharat Biotech in collaboration with the ICMR. The phase-three randomised double-blind placebo-controlled multi-centre trial of Covaxin cover around 28,500 subjects aged 18 years and above and are being conducted in around 25 sites across 10 states.

The UK’s decision to permit Pfizer and its partner BioNTech’s Covid-19 vaccine has created an emergency in India to build infrastructure to support the vaccination process. With three anti-Covid vaccines under regulatory review for emergency use, the government is gearing up with 28,947 cold chain points with 85,643 pieces of equipment across the country that are capable of storing the vaccines needed for the first set of three crore health and frontline workers.

The centre is mobilising additional vaccinators, a digital platform for vaccine delivery and a detailed implementation plan to inoculate around 30 crore priority population in the first phase expected to get underway soon. The government is procuring additional cold storage capacities, and supply of equipment to states will begin soon according to the health ministry.

Interestingly, even as India is gearing up for the Covid-19 vaccination programme, the daily cases in the country continue to fall after peaking about three months ago. India is now one of the only two countries among the 10 worst-affected by the pandemic that are yet to be hit by a second wave of infections. 

What is a vaccine and how does it work?

But while the entire world is heaving a sigh of relief that the Covid-19 vaccine has arrived, the question that arises is: What is a vaccine and how does it work? A vaccine is a type of medicine that trains the body’s immune system so that it can fight a disease it has not come into contact with before. Vaccines are designed to prevent disease, rather than treat a disease once caught. Vaccines contain a dead or weakened version of a microbe. It helps the immune system to recognize and destroy the living microbe during a future infection.

The concept behind vaccines is to stimulate an antibody memory response without producing an actual illness. When this happens, the person gets the immunity without getting sick. A vaccine must contain at least one antigen from the bacteria or virus in order to get a response.

A vaccine works by training the immune system to recognize and combat pathogens, either viruses or bacteria. To do this, certain molecules from the pathogen must be introduced into the body to trigger an immune response.

These molecules are called antigens and they are present on all viruses and bacteria. By injecting these antigens into the body, the immune system can safely learn to recognize them as hostile invaders, produce antibodies, and remember them for the future. If the bacteria or virus reappears, the immune system will recognize the antigens immediately and attack aggressively - well before the pathogen can spread and cause sickness.

A vaccine contains the dead or weakened but alive micro-organisms of a disease. When the vaccine containing the micro-organisms is introduced into the body of a healthy person orally or by injection, the body of that person responds by producing some substances called antibodies in its blood. These antibodies kill the disease-causing microorganisms present in the vaccine. Some of the antibodies remain in the blood of the person for a long time and fight against the same micro-organisms and kill them if they enter the body naturally later. So, due to the presence of the antibodies in the blood, a person remains protected from that particular disease.

History of vaccine

Edward Jenner, a British physician, is considered the founder of vaccinology after he inoculated a 13-year-old-boy with vaccinia virus (cowpox) in 1796 and demonstrated immunity to smallpox. In 1798, the first smallpox vaccine was developed. Over the 18th and 19th centuries, systematic implementation of mass smallpox immunisation culminated in its global eradication in 1979.

Louis Pasteur’s 1885 rabies vaccine was the next to make an impact on human disease. And then, at the dawn of bacteriology, developments rapidly followed. Antitoxins and vaccines against diphtheria, tetanus, anthrax, cholera, plague, typhoid, tuberculosis and more were developed through the 1930s.

The middle of the twentieth century was an active time for vaccine research and development. Methods for growing viruses in the laboratory led to the rapid discoveries and innovations including the creations of vaccines for polio. Researchers targeted other common childhood diseases such as measles, mumps, rubella and vaccines for these diseases reduced the disease burden greatly.

Innovative techniques now drive vaccine research with recombinant DNA technology and new delivery techniques are leading scientists in new directions. Disease targets have expanded and some vaccine research is beginning to focus on conditions such as addiction and allergies.

Since then, new vaccines have become available. Some of them including hepatitis B, rotavirus, haemophilus influenzae Type B and pneumococcal vaccines are recommended by the WHO for global use.

Based on the emerging success of the smallpox programme, in 1974, the WHO launched the Expanded Programme on Immunization (EPI). The initial EPI goals were to ensure that every child received protection against six childhood diseases namely polio, diphtheria, pertussis, tetanus and measles by the time they were one year of age and to give tetanus toxoid vaccinations to women to protect them and their newborns against tetanus. By 1990, vaccination was protecting over 80% of the world's children from the six main EPI diseases, and other new vaccines are continually being added to the EPI programmes in many countries.

Covid – 19 vaccines

The vaccine development is a long, complex process, often lasting 10-15 years and involving a combination of public and private involvement. It took 26 years to develop a vaccine for the human papilloma virus, for instance, and 25 years to secure one for rotavirus. And researchers have been trying for more than 50 years to find a vaccine against the respiratory syncytial virus, one of the leading causes of infectious disease mortality in infants.

The list of elusive vaccines is long. One of the most frustrating quests has been for a malaria vaccine. The fact that the WHO recently announced that it was exceedingly pleased with a new vaccine that protects just 30% of those immunized indicates the immense difficulty of producing a malaria vaccine. And no discussion of vaccines is complete without assessing the potential of an HIV vaccine in the twenty-first century. Like plasmodium, the HIV retrovirus is a wily and insidious microbe. Most attempts to develop an HIV vaccine have ended in failure.

But then, Covid-19 was different from any epidemic the world has seen in recent years -- it affected the countries across the world in no time and people rich and poor died in equal numbers.  A vaccine for the Covid-19 virus, formally known as SARS-CoV-2, became the focus of unprecedented research efforts. Over 100 research groups have vaccine candidates under development and some of them are already being tested in people. And finally, the UK gave Pfizer and its partner BioNTech’s Covid-19 vaccine a green light and the first doses were given on December 8.

The speed with which Covid-19 vaccine has been developed is remarkable as compared with a typical timeline of three to nine years. The rapid pace of development of vaccines against Covid-19 is enabled by several factors: prior knowledge of the role of the spike protein in coronavirus pathogenesis and evidence that neutralizing antibody against the spike protein is important for immunity; the evolution of nucleic acid vaccine technology platforms that allow creation of vaccines and prompt manufacture of thousands of doses once a genetic sequence is known and development activities that can be conducted in parallel, rather than sequentially, without increasing risks for study participants.

The vaccination programme will be rolled out across England, Scotland, Wales and Northern Ireland and is being closely monitored by governments and public health officials around the world. While the vaccine has been widely welcomed and is seen as a giant relief after months of death and uncertainty caused due to the pandemic, there is scepticism about how successful it will be.

But while the world is waiting to see the result of the Pfizer’s Covid-19 vaccine in the UK, Russia began vaccinations with its Sputnik V vaccine, and China has also begun giving its own domestically made shots to its citizens and selling them abroad. But those are being viewed differently because neither country’s vaccines have finished the late-stage trials that scientists consider essential for proving a serum is safe and effective.

Other vaccines are also being reviewed by regulators around the world including one in collaboration between Oxford University and drug maker AstraZeneca and the other developed by the US biotechnology company Moderna.

As hopes for an early arrival of a potential vaccine for Covid-19 rise, experts caution that logistical problems could threaten the Indian government's efforts to swiftly carry out a mass vaccination drive. Vaccinating over 1.3 billion people is a mammoth task. India hopes to receive up to 500 million doses of coronavirus vaccines by July next year to inoculate about 250 million people. However, India’s biggest advantage is that it has a robust immunisation programme in place and it is implementing the largest immunisation programme of the world, with nearly 27 million new borns targeted for immunisation annually.

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