Article by : Shreyanshi Dubey | 24th December, 2020
Public health can be defined as an art of preventing diseases, prolonging life and promoting health through the organised efforts and informed choices of society, organisations, communities and individuals. As the world is actively anticipating the development of covid 19 vaccine it is interesting to look into the history of vaccinations. But before we dive into the history of vaccine development, it would be interesting to know what do we understand by the term vaccine?
As defined by World Health Organisation a vaccine (or immunization) is a way to build body’s natural immunity against a disease before one might get sick. This keeps the person from getting and spreading the disease.
So how does a vaccine function?
For most vaccines, a weakened form of the disease germ is injected into a person’s body. This is usually done with an injection shot in the leg or arm. The body detects the invading germs (antigens) and produces antibodies to fight them. Those antibodies then stay in that body for a long time. In many cases, they stay for a lifetime. Thus in future if that person is ever exposed to the disease again, their body will fight it off without they ever getting the disease.
Just a few generations ago, people lived under the constant threat of deadly infectious diseases, like smallpox, polio, and hepatitis.It was during this time that many physicians and medical science enthusiasts started to explore the possibility of development of vaccines. Arguably the single most life-saving innovation in the history of medicine the vaccines, have eradicated smallpox, slashed child mortality rates, and prevented lifelong disabilities.
Possibly lesser known, however, are the historic events and impressive works of the pioneers of medical sciences. We should thank them today for not only saving millions of lives each year, but for laying the foundations of future vaccine development — something that is front-of-mind as the world rushes to make a viable coronavirus vaccine.
Historical development of vaccines
In the 14th and 15th century small pox alone was responsible for millions of death across the globe and history remarked it as the most feared illness. Many early attempts were made to inoculate people against this deadly disease in the 16th Century.. With a death rate of 30% were reported in China grounded Smallpox scabs were blown into the recipient’s nostrils or scratched into their skin. This practice, known as “variolation”, became popular for a ehile and reached Europe in 1721, which was endorsed by an English aristocrat Lady Mary Wortley Montagu. However this practice was later met with public outcry after it transpired 2–3% of people died after inoculation, and further outbreaks were triggered.
The next safer and refined iteration of the practice of inoculation, originated with the observation that dairy farmers did not catch smallpox. The 18th Century English physician, Edward Jenner, hypothesised that dairy farmers developed a mild infection with cowpox which might be responsible for the suspected protection against smallpox. And so, he set to work on a series of experiments, now considered as the birth of immunology, vaccine therapy, and preventive healthcare treatments.
Today we can safely assume that the scientific advancement in vaccinology initiated only in the 18th century. When Edward Jenner in 1796 inoculated a 13 year-old-boy with vaccinia virus (cowpox), and demonstrated immunity to smallpox. He eventually came to be known as the father of Vaccinology. His efforts resulted in the development of first smallpox vaccine in 1798. Over next 2 centuries, a systematic implementation of mass smallpox immunisation culminated in its global eradication in 1979. This led to mass research and scientific advancements in the study of vaccine development.
We must note that vaccine development was a long drawn continued process. After the development and successful execution of smallpox vaccine, a century later in 1885, the French biologist, Louis Pasteur, saved a nine-year-old boy’s life when he was bitten by a rabid dog, by injecting him with a weakened form of the rabies virus each day for 13 days. The boy never developed rabies and the treatment was heralded a success. Pasteur coined his therapy a “rabies vaccine”, expanding the meaning of vaccine beyond its origin.
Pasture’s work popularised the term vaccine globally. Eventually resulting in a long list of treatments which contained live, weakened or killed viruses, typically given in the form of an injection, to produce immunity against an infectious disease.
These scientific advancements in the first half of the 20th Century led to an explosion of vaccines that protected against whooping cough (1914), diphtheria (1926), tetanus (1938), influenza (1945) and mumps (1948). By the 1940s the technique of disease prevention through vaccines reached new heights. Thus setting global vaccination and disease eradication efforts in motion. Another significant victory for modern medical sciences was, when Louis Pasteur’s experiments spearheaded the development of live attenuated cholera vaccine and inactivated anthrax vaccine in humans (1897 and 1904, respectively). We must not forget that it was the time when humanity was dealing with deadly diseases like Plague, for which the vaccines were invented as late as in the 19th Century. Between 1890 and 1950, bacterial vaccine development proliferated, including the Bacillis-Calmette-Guerin (BCG) vaccination, which is still in use today.
Vaccines against polio (1955), measles (1963), rubella (1969) and other viruses were added to the list over the decades that followed.
Various methods used in development of vaccines:
Viral tissue culture method-
This method was developed from 1950–1985. It led to the advent of the Salk (inactivated) polio vaccine and the Sabin (live attenuated oral) polio vaccine. Similarly, this technique led to the development of attenuated strains of measles, mumps and rubella for inclusion in vaccines.
Molecular Genetics Technique
The past two decades have seen the application of this technique and increased insights into immunology, microbiology and genomics applied to vaccinology. Current successes include the development of recombinant hepatitis B vaccines, the less reactogenic acellular pertussis vaccine, and new techniques for seasonal influenza vaccine manufacture.
Molecular genetics set up the scene for a bright future for vaccinology, including the development of new vaccine delivery systems (e.g. DNA vaccines, viral vectors, plant vaccines and topical formulations), new adjuvants, the development of more effective tuberculosis vaccines, and vaccines against cytomegalovirus (CMV), herpes simplex virus (HSV), respiratory syncytial virus (RSV), staphylococcal disease, streptococcal disease, pandemic influenza, shigella, HIV and schistosomiasis among others.
Global efforts in vaccine delivery mechanism and its constraints
From early 20th century onwards, the vaccination rates shot up dramatically due to successful global health campaigns supported by various health and charity organisations. It has resulted in successful eradication of many life threatening and crippling diseases. For example the mass polio immunisation has now eradicated the disease from many regions around the world, measles on the other hand is currently the next possible target for elimination via vaccination.
However, despite the evidence of health gains from immunisation programmes there has always been resistance to vaccines in some groups. The late 1970s and 1980s marks a period of increasing litigation and decreased profitability for vaccine manufacture, which led to a decline in the number of companies producing vaccines. The decline was arrested in part by the implementation of the National Vaccine Injury Compensation programme in the US in 1986. The legacy of this era lives on to the present day in supply crises and continued media efforts by a growing vociferous anti-vaccination lobby.
In response, the Bill and Melinda Gates Foundation and partners came together in 2000 to set up the Global Alliance for Vaccines and immunization, now called Gavi, the Vaccine Alliance. The aim is to encourage manufacturers to lower vaccine prices for the poorest countries in return for long-term, high-volume and predictable demand from those countries. Since its launch, child deaths have halved, and 13 million deaths have been prevented.
Protection against long-standing illnesses will continue to be important in the decades and centuries ahead, but the work is not complete. In order to protect the world against infectious diseases, we need a mechanism to monitor new viruses, and rapidly develop vaccines against the most dangerous emerging infections. The devastating 2014/2015 Ebola virus was a wake up call for how ill-prepared the world was to handle such an epidemic. A vaccine was eventually approved but came too late for the thousands of people who lost their lives.
In response, the Coalition for Epidemic Preparedness Innovation (CEPI) was launched at Davos in 2017 which is a global partnership between public, private, philanthropic, and civil society organizations working to accelerate the development of vaccines against emerging infectious diseases and enable equitable access to these vaccines for affected populations during outbreaks.
We’ve come a long way since the risky and gruesome early inoculation efforts five centuries ago. Scientific innovation, widespread global health campaigns, and new public-private partnerships are literally lifesavers. Finding a vaccine to protect the world against the new coronavirus is an enormous challenge, but if there’s one thing we can learn from history, it’s that there is reason for hope.