GREEN THUMBS

 

               BATTLE BETWEN PATHOGEN & HUMAN BEING

Vaccine is a burning issue worldwide since outbreak of Covid-19 in December, 2019. In India the first case of Covid-19 was reported in Jan. 2020. Each and everyone be it medical community, drug manufacturing companies, scientists/researchers, public at large, various governments in the world etc.is anxious and keen to follow the progress made in development of Vaccine against Covid -19. While there is a substantial improvement in development of anti-Covid vaccine, detailed subsequently, I would like to discuss, in brief, certain important aspects/features of the vaccine 

 

2. We are well aware that vaccines are one of the most important tools in combatting infectious diseases. Before the discovery and widespread use of vaccine, many infectious diseases were responsible for mortality and morbidity in millions of people. Entire world has witnessed that over a period of time, vaccines have tremendously and dramatically improved human health. An effective vaccine would increase immunity to the virus, because it guides/trains the body’s immune system to fight off a disease it has not encountered before. Here it is also important and pertinent to make distinction between medicine and vaccine:

 

              "Medicine is a made of ingredients. It does not provide immunity against a disease. In fact, it works after the disease has occurred. It is a reactive and curative in nature."

      "Vaccine is a biological preparation that provides acquired immunity to a particular Infectious disease. The agent (explained in para 5 below) present in   vaccine stimulates the body's immune system.  It is a proactive in nature and a preventive system. In simple terms, we may appropriately call it”लोहा लोहे को काटता है।"

             

To be precise -Vaccine is a suspension of weakened, killed or fragmented microorganisms or toxins of antibodies that is administered primarily to prevent disease - as defined by Wikipedia.

         

 3. But it is a tedious, difficult and complicated process to develop/manufacture vaccines. Apart from requirement of huge investment/funds and consumption of time, the process to develop safe and affordable vaccines has to undergo rigorous safety procedures before it is widely made available and distributed for  its end users.

 

 "A 2013 paper from the University of Rotterdam found that, on average, it takes 10.7 years to develop a vaccine. Although the record is four years, for a vaccine against mumps in the 1960s”

Similarly, though Ebola virus was first discovered in 1976 (in Congo), the vaccine for the same was approved recently in later part of year 2019. It took about 43 years for developing and approval of the Ebola vaccine.

 

 4.  The first vaccine was introduced way back in 1796 by British physician Edward Jenner.  He used the cowpox virus to confer protection against smallpox. As on date, the WHO list 28 diseases for which vaccines are available. There are certain under ' Pipeline Vaccines'. It is a list of diseases for which vaccines are at different stages in development.

 5 Primary challenge in vaccine development is devising a vaccine strong enough to ward off infection without making the individual seriously ill. Safety of an individual is of paramount important in the whole process.  There are mainly four types of vaccines devised by researchers.

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 (i) Live-attenuated vaccines: consist of microorganisms that have lost the ability to cause serious illness but retain the ability to stimulate immunity.

                               E.g.     Measles, Mumps & TB etc.

 

 (ii) Inactivated vaccine :  use killed version of the germ that causes disease.  These vaccines usually don't provide immunity( protection) that's as strong as live vaccines.  As such, higher quantities of inactivated vaccines are administered.

                         E.g. Vaccines against Rabies & Hepatitis

  

(iii)  Subunit, recombinant, polysaccharide, and conjugate vaccines.

These vaccines use specific process of the germ----like it proteins, sugar or capsid ( a casing around the germ)

                     E.g. Hepatitis B &Whooping cough

(iv) Toxoid vaccines

Toxoid vaccines use a toxin (harmful product) made by the germs that causes a disease. They create immunity to the part of the germ that cause a disease instead of the germ itself.  In simple terms it means the immune responses is targeted to the toxin instead of the whole germs.

                   E.g. Diphtheria & Tetanus

 6. Having listed out the type of vaccines, I would now like to briefly touch upon the stages involved in its development / manufacture. 

 First Step: Laboratory and Animal Studies

Exploratory State

The stage involves basic laboratory research.  Scientists identify natural or synthetic antigens that might help   prevent or treat a disease. 

Pre-Clinical State

Pre-clinical studies use tissue -culture/ cell-culture systems and animal (may include mice and monkeys) testing to assess the safety of the candidate vaccine and its ability to provoke an immune response. 

Next Steps: Clinical Studies with Human Subjects 

Phase I Vaccine Trials

The first attempt to assess the candidate vaccine in humans involves a small group of adults ( say between 20- 80 subjects). The goal is to assess the safety of the candidate vaccine and to determine the type and extent of immune response that the vaccine provokes.  The participants  in these studies are carefully monitored.

   Phase II Vaccine Trials 

In this phase of trial a group of several hundred individuals participate.  It may also include some of the individuals who may belong to groups at risk of acquiring the disease.. Of course, trials are to be well controlled. The goals of Phase II trials are to study the candidate vaccine's safety, immunogenicity, proposed doses, schedule of immunizations and method of delivery.

Phase III Vaccine Trials 

Once the Phase II is successful,  candidate vaccine move on to larger trials.  (The stage may involve thousands to tens of thousands of people) . The objective is to assess vaccine safety in a large group of people as certain rare side effects might not surface in the smaller groups of subjects tested in earlier phases.  Vaccine efficacy is also tested in this phase.

 Next Steps :  Approval and Licensure

After a successful Phase III trial, the vaccine developer is to obtain necessary approval and License from the appropriate Regulatory Authority.

 7. Now I would like to present the status of development of vaccine candidates against Covid-19 in India as it must be of primary concern to all of us.

                        

                          FOUR MAJOR VACCINE CANDIDATES UNDER TRIAL IN INDIA

 

S. No.	Name of Vaccine	Developer/ Manufacturer	Collaborator	Present Status	Remarks
01	Covaxin	Bharat Biotech	ICMR	Phase III Human Clinical Trial, ONGOING	‘Not considered’ for EUA. . CDSCO has sought more data to clear the vaccine candidates
02	Covishield	Serum Institute of India Limited	Oxford University-Astro- Zeneca	Phase II/III Human Clinical Trial, ONGOING
03	ZyCoV-D	Zydus Cadila	Deptt. of Biotechnology of India	Phase II Human Clinical Trial, ONGOING
04	Sputnik V	Dr. Reddy’s Laboratories Ltd.	Sputnik LLC	Phase I/II Human Clinical Trial, ONGOING

 

 8. From the data tabulated above, one would observe that the progress made in development of vaccine candidates is worth appreciating.  The vaccination of huge population is a serious challenge ahead in terms of Logistic supports, creation and strengthening of cold chain storages facilities/infrastructure, to ensure distribution and transportation of vaccine to the  remotest reach of the country, effective and sustained communication on vaccine drive, availability of  sufficient trained vaccinators across the country, cost of vaccine and prioritization for vaccination groups.   However, it is a matter of satisfaction that  both the Central as well as State Governments are well aware of the issues. They are sincerely and seriously engaged on war-footing to sort out all these complexities so as to ensure vaccination of people residing even in remotest and inaccessible areas.

9. I am sanguine, as advised by our Government; process of vaccination may begin from the first quarter of 2021. My humble request is till then treat masks as vaccination substitutes and maintain social distancing. Of course, do not forget to wash your hands with soap, frequently

                                                  STAY HOME, STAY SAFE.