The Covishield and Covaxin -To Prick or not to Prick?

I took the first dose of Covishield two weeks back. A day of mild fever and malaise followed. That is good. Just my body developing protection from Covid19.

Our government have started administering Covaxin, a vaccine developed and made by an Indian Private company, Bharath Bio Tech.

Covishield too, is made in India by the Serum Institute. But it was developed by Astra Zeneca, a British- Swedish company, with help from Oxford.

There is a controversy now. Should we give Covaxin, at all?

Well, what is the difference between them?

Technical differences we should leave. Both are made differently, and the principle vary slightly. Covishield is a piece of DNA wrapped in an Adenovirus vector, and Covaxin is a more traditional, inactivated virus vaccine.

But that is not the issue here. When we started administering Covishield, It had completed three stages of clinical trials, a series of tests made mandatory in this modern era, for any drug with significant effect on the human body.

Stages of a drug trial:

The first stage is testing in cells in issue culture, and animals. We need to look for two things in any trial – Safety and Efficacy.

Safety- How safe is it? What are the side effects, if any?

Efficacy- How effective is the drug? (here, does it protect against Covid?)

During animal studies, we see whether the animals develop any adverse effects. We also see whether they develop Antibodies against the virus of Covid19. We know that if Antibodies develop, we can REASONABLY EXPECT, SOME PROTECTION. This is what we know from general immunology.

Now, we need to test the vaccine, in humans. We have to be extra careful. It is done in three Phases.

Phase1: The vaccine is given to a small (usually less than 100) number of HEALTHY people. We look at three things:

  1. Are there any side effects?
  2. What is the dosage to be given?
  3. Is there an antibody response?

Phase 2: If the results of Phase1 are favorable, we move to Phase 2. In this we use more people, usually, 100 to a 1000. They are also a POPULATION SAMPLE, from the general population, and need not be healthy younger ones. Again, we are looking at side effects, perfecting the dosage, and looking for the development of antibodies.

Suppose the side effects are minimal. And there are antibodies. Hurray!

Hey- Not so fast. Don’t bring out the champagne bottles just yet. Save the fizz for a bit. Three questions remain unanswered.

  1. Antibodies are fine. Does the vaccine, actually prevent Covid 19?
  2. What is the exact risk reduction?
  3. Does it have rarer, serious side effects that may not be detected by testing on less than 1000 or so humans?

The Phase 3 is the actual challenge for any Drug manufacturer. It is called the valley of death. THIS is what makes newer drugs and vaccines so hard to produce. THIS is where most nascent drugs die, unborn.

Phase 3: Here, tens of thousands of people are recruited. Pfizer vaccine did a trial in 44000 people before it was approved. Covishield did for around 17000 humans before we approved it. The Phase 3 is usually a proper RANDOMISED CONTROLLED TRIAL. The participants are divided randomly into two groups, and one group is given our vaccine, and one group is given a dummy drug, like saline or so.

Then the groups are followed up for a period of time, and any side effects are closely monitored. And, –

How many develop Covid 19 in each group? Is there a sizable difference? How big is the difference? How effective is the vaccine in actually preventing the disease? For instance, we know that the Pfizer vaccine is around 90 percent effective, and Covishield, around 70 percent.

This is the issue. Covaxin did not have a Phase 3 before it was approved. We do not really know whether it is effective and by how much. We do not know if any rarer side effects are possible.

The approval of Covaxin in “clinical trial mode” is what is being questioned by some. What is clinical trial mode? No proper consent is taken. There are no two groups. We can look at the efficiency after it is given to thousands of people, and compare it to Covishield later, in a rough inexact way, after some time. But no proper controlled trial is possible now.

Dear folks. This is the gist.

Now we part ways with the facts, and move on to factionalism. Where you stand in the debate depends , it seems, on where your loyalties is lie. If you are an ardent nationalist, the answer is clear:

Hey. Athmanirbhar! We want ‘our’ vaccine to be used. This is an emergency Pandemic situation, dammit! It produces antibodies, and that is it. Chapter closed.

If you are a reasonable nationalist, or a purist for procedures, you say:

But we have enough Covlishield doses! We have 6 crore vials and have used only 60 lakhs! Why should we abandon proper procedure? Then we could have started using China’s Sinovac and Russia’s sputnik four months back, both of which were released after just two phases and without a proper Phase 3. We could have vaccinated millions by now! Then, it was an unproven vaccine for us, and we didn’t approve!

Then they come back with:

Come on, have you no loyalty?

And- it is time to stop. We are already in dangerous, difficult-to-get-bail territory (Jimmy Mathew)

Dr Jimmy

I am a Doctor, Writer and Science Communicator. I am a member of Info- Clinic, and have written a few books. This site features my blog posts and stories. Thank you for visiting. ഞാൻ എഴുതാൻ ഇഷ്ടമുള്ള ഉള്ള ഒരു ഡോക്ടർ ആണ് . നിങ്ങളുടെ താത്പര്യത്തിന് നന്ദി .