AstraZeneca’s admission in a UK court that its Covid vaccine can cause a rare side-effect has sparked concern, especially in India. Is there cause for worry?
This is not new. It has been coming up since 2021. Based on The Telegraph report that everyone seems to be referring to, what did AstraZeneca admit? It said there was a very rare chance of something called TTS. TTS is thrombosis and thrombocytopenia syndrome. Thrombosis means blood clots, thrombocytopenia means a reduction in the level of platelets. Platelets prevent bleeding so people who have low platelets bleed at the slightest provocation and this bleeding leads to internal clotting. A dengue virus infection can also cause thrombocytopenia. So they have admitted to a very rare event.
Now, how rare is very rare? Different countries have computed their own risk. The UK computed a risk of four cases of TTS in 1 million vaccinated people. The EU has computed it to be one in 100,000 and Australia 2-3 per 100,000. So this is extremely rare. In India, we don’t know this because there have been no studies. Looking at this risk, I would say it’s no cause for worry. Now to put some perspective to what this risk means. The highest figure is 2-3 per 100,000 people. If you look at the risk of dying in a traffic accident, the global average is 17-18 per 100,000. So at its worst, the AstraZeneca vaccine has a TTS risk which is five to nine times lower than the risk of dying in a traffic accident. That doesn’t stop us from driving. But in election time in India, vaccines have suddenly become a political issue (again). It was made a political issue by the ruling dispensation and now the opposition is trying to play politics with it. That’s wrong. That’s dangerous. It shouldn’t be done.
Could you explain the connection between the vaccine and TTS ? Is it known why it happens?
Essentially, this vaccine is based on a live adenovirus particle. It’s a chimpanzee adenovirus in which the Covid virus surface protein gene has been engineered. Why exactly clots happen is not clearly known. But going back to the dengue virus example, where that virus also causes a loss in platelets, it happens because the virus possibly actively kills platelets or it infects cells which release substances that kill platelets. So my suspicion is that the adenovirus also, in rare instances, causes something like that. But the whole point is the risk is so low and the benefits of taking the vaccine are so high that it makes sense to take the vaccine.
Do all vaccines carry some risk? How do regulators weigh this risk versus benefit?
Every vaccine carries a risk. Take the highly successful oral polio vaccine, which has been used not just in India but all over the world. That vaccine itself has a one in a million chance of causing polio in children. Now, if you see this from the perspective of that one child in the million, the risk is 100%. But if you look at it from a population perspective, then the benefits far outweigh the risk. We have to realise that vaccines are tools for public health and if the benefit far outweighs the risk, then you use it. Now, the main difference between other vaccines and Covid vaccines was that these were developed during an ongoing pandemic. This is the first time that a vaccine was used to stop a pandemic. If you had the benefit of testing the vaccine for 10 years before you release it, you could possibly test some of these. But if the risk is 2 in 100,000 you would have to test it in at least a million plus to see that risk show up.
Which vaccine is tested in a million people before it is released? None. So do you keep testing it ad nauseam till you come up with all these rare risks? Or do you deploy it in a public health emergency?
Regulators look at clinical trial data. But the job of the regulator doesn’t stop only when the vaccine is approved. There’s what we call Phase IV studies, after the vaccine is deployed. It’s like with any product — after it is released, you conduct market surveys to find out they’ve been successful. The regulator should continuously look at data coming from the field after the vaccines have been deployed to understand if something really is going wrong, (and if it is) then they should stop.
The UK eventually stopped the rollout of AstraZeneca vaccine but in India that was the vaccine that was used the most. Do you think India should have done anything differently?
The decision initially to deploy Covishield and Covaxin was the right decision because those were available in plenty in the country. But later when it came to booster vaccinations, global data was clear that a third dose of Covishield or a third dose of Covaxin doesn’t do much good. And by that time, India had also developed and approved some protein vaccines. For example, Serum Institute of India (which also made Covishield) had made Covovax. My view is that for booster doses, we should have deployed protein vaccines. But by the time those were approved for boosters, it was too late.
In the wake of AstraZeneca’s admission in court, there seems to be this new support for those who avoided getting vaccinated. How would you respond to that as a virologist?
It is sheer stupidity. Look at global data. I will cite just one study from the US which looked at Covid-related mortality between Republicans and Democrats. The study looked at those counties that voted for Trump as president versus those that voted for Biden. When they looked at Covid-related mortality in 2020, before vaccines became available, there was no difference.
But once vaccines became available, the mortality in Republicans was significantly higher than the mortality in Democrats. What does that tell you?
That all the misinformation and rhetoric around vaccines that Donald Trump stated had an impact on his committed voters. Trump took the vaccine, he had the best drugs available, but many of the people who listened to him didn’t survive. What our politicians say and do when it comes to using public health tools is very important. Vaccines are possibly the safest and the most effective public health tool available to us. Period. ‘Every Vaccine Carries a Risk. If Benefits Outweigh it, You Use It’ After India lost its dominance in making penicillin, a drought of three decades is coming to an end.
The drug – which forms the base for a raft of extremely potent antibiotics – is part of the government’s aggressive push for self-sufficiency in critical areas. Will the plan to claw back to the glorious past work? 6000 5000 4000 3000 2000 1000 0 Mar ’20 Mar ’21 Mar ’22 Mar ’23 Mar’ 24 MAT Value in ` cr 5-year CAGR 8% INDIA MARKET: GOING STRONG 3,744 3,1774,1254,813 5,056 MAT: Moving annual total Source: Pharmatrac Experts say while the govt is aware of the risks from China’s imports, there are concerns over selfsufficiency plans. “What is the guarantee the Chinese will not crash prices again?” says an analyst.
