We are now many months into this COVID-19 pandemic, just one month more to go before it completes one year. The pandemic is still raging on, the virus is still lurking around in our midst, it seems to be evolving somewhat, and most of us continue to be vulnerable and at risk of catching the infection. It is obvious this virus is not in a mood to go away soon. With winter approaching, the infection rate seems to be climbing up. In many parts of the world, second and third waves of infections are being witnessed. So we do not see a complete resolution of this ongoing problem in the immediate future. Moreover, nobody is in a position to predict for how long the pandemic is going to continue. Herd immunity is still a long way to go. People and governments alike are all trying very hard to bring back life to the normal pace and situations, but it’s a tough job. What we are now looking forward to and counting on is a viable vaccine to help neutralize the SARS-CoV2 virus and help the body in fighting COVID-19. The situation that we are in now is a tricky one, and it is felt that a vaccine which has the capacity to produce long-term immunity is one means that will bail us out of this tight spot.
Since the beginning of this pandemic earlier this year, there has been so much talk about a COVID-19 vaccine. If it had not been for this, people would never have bothered so much about vaccines. As the need for the vaccine is an emergent one, much emphasis on it is being given. In this write-up I’d like to share some basic information about vaccines and the story of how vaccines came to exist. This information is more so for the understanding of the laymen who do mention the word vaccine but is not sure what it is in actuality.
Prevention is better than cure. I’ll begin by stating that vaccine is not a curative agent but a preventive one. The mechanism by which a vaccine works is based on immunity. So what is immunity? Immunity is the response of the body to anything that it considers foreign to itself. When a host body gets an infection due to a pathogen i.e., bacteria, virus, or protozoa, the body tries to fight these foreign materials in many ways. The defence mechanism includes production of antibodies as well to fight the pathogen. The antibodies in turn neutralize the antigens which are the pathogenic particles. That way, the body gets cured of the disease. Most of the time, these antibodies remain in the body even after the disease is gone and keeps the body protected from the same disease if it were to attack once again. This is how immunity is developed in a body.
Immunity against a specific pathogen can be achieved or developed without getting sick by a process called immunization. It is here that vaccines and vaccinations come into the picture. Immunizations are done by vaccination. When a vaccine is introduced into the body, it triggers an immune response within the body to fight away the disease just like the way the body responds when the actual pathogen invades the body naturally.
A vaccine is a preparation that contains dead or weakened version of a microbe. The immune system recognizes this as the pathogen itself and helps in destroying the living microbe if a future infection occurs. The body is tricked into believing that it is attacked by the real pathogen.
The practice of immunization dates back hundreds of years. In ancient times, Buddhist monks drank snake venom in order to get immunity to snake bites. The history of vaccination and the story of vaccines starts with the once dreaded disease smallpox. It is not anymore at the moment as it has been eradicated from the face of this earth, the credit of which goes to vaccines. At one time, like tuberculosis, it was felt that smallpox would remain permanently and continue to affect human lives drastically, but the smallpox virus is now present only in two laboratories in the world, one in the United States and the other in Russia.
Smallpox was an extremely severe infectious disease known to mankind from time immemorial. It was not known at that time that it was caused by a virus. The disease killed millions of people and left lots scarred for life. In the 18th century, half a million Europeans died of smallpox every year, and even further into the 20th century, it was still claiming many million lives. Of the people affected by the disease, some died, some survived, and those that survived then became immune to it, but the disease left the surviving ones with lots of damages. The mention of smallpox is found in the ancient texts of India. It is seen in the mummies of Egyptian pharaohs. It caused havoc in ancient Rome and affected the indigenous societies of the Americas. A lot of people would get it in their lifetimes. In children, the mortality rate was very high, around 80%. The disease was very difficult to manage on an individual level. Infected people needed constant care, caregivers easily got the disease, whole families got wiped out many times, and the survivors were left with lifelong damages of deep pitted facial and bodily scars, loss of eyelashes, and even blindness. Locally, we do not have much documentation about the prevalence, but we were definitely witness to poke-marked faces, a remnant of smallpox, in people belonging to the generation of our parents and grandparents.
In the middle ages, the Chinese had developed a technique to get immunity from smallpox. The process was called insufflation. Scabs from individuals with mild case of smallpox were collected. Those scabs were allowed to dry and then grounded into a powder. The powder was then rafted in cotton, the material packed into a pipe and then was puffed into the nose of a person who had not been infected by the disease. So this appears to be the first documented use of inoculation which is a deliberate infection to trigger immune response. Thus, the idea of vaccination stemmed from here.
There was another method too, a process called variolation. This was also practiced by the Chinese in the seventeenth century. Humans suffer from smallpox while cows suffer from cowpox. Cowpox is somewhat similar with smallpox but cowpox is not so severe compared to smallpox. In the process of variolation, tears in the skin were smeared with cowpox material in an effort to confer immunity to smallpox. So most likely immunity against smallpox was achieved.
The formal practice of vaccination was pioneered by an English doctor by the name of Edward Jenner. He is also referred as the Father of Immunology. He was born in Berkeley, Gloucestershire, in 1749, the son of the local vicar. At the age of 14, he had apprenticed to a local surgeon and then trained in London. In 1772, he returned to Berkeley and spent the rest of his career as a doctor in his native town.
As it had been the case always, around Jenner’s time also, smallpox was a dreaded disease, but more importantly, he made one startling observation. He noticed that cows had infection similar to smallpox but a milder form of it known as cowpox. What was more surprising was the fact that milkmaids who came in close contacts with these infected cows never contacted smallpox. In fact, they were rather beautiful without the scars or scabs from the disease. Smallpox usually leaves the sufferers with lifelong scars. He felt there must be a correlation here. He assumed that cowpox infection seemed to protect humans against smallpox, and he decided to check this out.
In 1796, Jenner carried out his legendary experiment on an 8-year-old boy by the name of James Phipps who was the son of his gardener. He inoculated the boy with cowpox material obtained from a blister on the hand of an English milkmaid. He was testing his theory. After a while, he inoculated smallpox material into the boy. The boy never fell ill and did not get the disease. He further tested the same with other subjects too and they never contacted the disease. This way, Jenner found the way to smallpox immunization out of curiosity and observation.
He submitted his experimental findings to the Royal Society but was told that his ideas were too revolutionary and that he needed more proof. He continued his experiment on several other children which included his own son. The results finally got published in 1798. The term vaccine was then coined by him and it was derived from the Latin word vacca meaning cow.
Hence, from here the practice of vaccination got its origin. This practice grew in popularity and eventually replaced variolation. His method underwent medical and technological changes over the next 200 years and eventually resulted in the eradication of smallpox in 1980 with the smallpox virus only existing now in two laboratories.
Over the years many more vaccines have been developed and used to prevent and eradicate many infectious diseases. The vaccine story so far has been a success. Without it, the infections diseases scenario would have been a completely different one from what we see now. On the COVID-19 front also, the trials are reported to be positive, and it looks like we are very close to a viable vaccine against this dreaded disease. In the meanwhile, we still need to abide by the safety precautions to be safe from it.