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AstraZeneca, and Now J&J: Decoding COVID Vaccines & Blood Clots

What do we know about the link between COVID vaccines and blood clots?

Updated
The recommendation comes from both the US FDA and CDC
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On 13 April, US health authorities Food and Drug Administration (FDA) and Centres for Disease Control and Prevention (CDC) have issued a statement calling for an immediate halt of Johnson & Johnson's COVID vaccine following reports of blood clots.

The FDA informed via Twitter that this recommendation was being made "out of an abundance of caution," until the vaccine is reviewed.

Not the First Set Back for Janssen

Concerns over the single-dose vaccine causing rare blood clot issues recently also drew scrutiny from EU's European Medical Agency (EMA).

Previously several Janssen vaccine sites were shut down across the US due to reports of other adverse reactions to the vaccine.

On top of that, earlier this month, contamination at one of their facilities in Baltimore led to nearly 13 million to 15 million doses of the vaccine being ruined.

Here's what we know so far about the Johnson & Johnson vaccine, the decision to halt it, and blood clots associated with COVID vaccines.

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Why Was the Vaccine Halted?

This decision was made after six recipients in the United States developed a rare disorder involving blood clots within about two weeks of vaccination, reported The New York Times.

Of the 6 people affected—all women between the ages of 18 and 48—one woman died, and another has been hospitalised in a critical condition.

“CDC will convene a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday (14 April) to further review these cases and assess their potential significance.”
US Food and Drugs Administration (FDA)

What is the Johnson & Johnson Vaccine?

First things first, here is a quick rundown on the vaccine in question.

Johnson & Johnson's single dose vaccine, Janssen, became the third approved vaccine for COVID-19 in the US, after Pfizer-BioNTech and Moderna COVID-19 vaccines.

Unlike the latter which are mRNA type, Janssen is a disabled adenoviral vector vaccine.

The vaccine was found to have an efficacy of 66.9% against moderate to severe/critical Covid-19 at least 14 days, and 66.1% at least 28 days after vaccination.

Apart from being a single dose vaccine, another logistical advantage that Janssen has is that it can be stored at temperatures between 2 and 8 degree Celsius, easing transportation and distribution, particularly in warmer countries.

What Is the Company Saying?

On 13 April, Johnson & Johnson released a statement addressing the issue, saying they are aware of their vaccine causing rare incidents of blood clots and low platelet count.

They also confirmed that the use of their vccine will be halted in the US and rollout in Europe will be delayed until the cases have been reviewed by both the concerned health authorities.

What are blood clots, and what causes it?

Blood clots are a clump of cells and protein in your blood that that form as a response to injury in order to help slow bleeding. It usually dissolves after you heal.

But if it doesn’t dissolve, or if it forms when it’s not needed, it can clog up or completely block a blood vessel.

They can cause severe problems like heart attacks and strokes.

Sometimes blood clots in your limbs could break off and travel to other organs like the lungs or the brain where it can prove dangerous.

Unusual blood clots are caused in the case of certain and illnesses like cancer, diabetes, and some genetic disorders.

What Do We Know About Blood Clots Associated With the COVID Vaccine?

Although a myriad of different ailments and drugs can raise the risk of blood clots in a person, the blood clots associated with the COVID vaccines are not the typical kind.

According to the the FDA, all the 6 patients had developed a rare type of blood clot called cerebral venous sinus thrombosis (CVST) in combination with low levels of blood platelets (thrombocytopenia).

This was also the case with the blood clots associated with the AstraZeneca vaccine.

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Are the blood clots the same as in the case of AstraZeneca vaccine?

Speaking at a press conference on 13 April, Peter Mark, Director, FDA Centre of Biological Evaluation and Research, drew parallels between the cases of blood clots in the two vaccines and said this,

” What’s notable here isn’t just the cerebral venous sinus thrombosis (CVST) or the or theThrombocytopenia but the occurrence of the two together that makes a pattern, and that pattern is very very similar to what was seen in Europe with another vaccine (AstraZeneca).”
Peter Mark, Director, FDA Centre of Biological Evaluationa and Research

"This is why we have to take the time to understand the complication and address it properly," he added.

Both Janssen and AstraZeneca are adenovirus vector type vaccines.

But given how rare the symptom is, experts suggest it is more likely caused due to an immune response of the particular recipients, than the technology on which the vaccines are based, a hypothesis also shared by Mark.

What about the other COVID vaccines?

So far over 18 million doses of Moderna and Pfizer vaccines have been administered in the US, of which no instance of unusual blood clots or low platelets have been reported.

In India, of the 11,11,79,578 people vaccinated, no cases of the rare blood clots have been reported in recipients of either Covaxin or Covishield vaccines.

Speaking to FIT on a previous article, Dr Shahid Jameel said this, “So far, in India there have been 234 hospitalisations recorded as adverse events and 71 deaths. But in none of these cases, deep vein thrombosis (DVT), which is essentially blood clotting, was observed.”

Who is at risk?

In the case of the Johnson & Johnson vaccine, women between the ages of 18 and 50 were affected, and symptoms occurred 6 to 13 days after vaccination.

In the case of the AstraZeneca vaccine too, most of the cases occurred in women.

However, we have very little information as of yet to say with certainty if any subgroup is more vulnerable than others.

How concerning are these reports of blood clots?

The extent of the side effect, and the causal link with the vaccine is yet to be determined.

But, considering only 6 out of the 6.8 million people who received the Janssen vaccine were affected by it, it is likely to be a rare occurrence.

Authorities have reiterated that blood clots associated with the vaccines (both Janssen and AstraZeneca) are extremely rare, and that the preemtpive decision to halt it’s use has been taken for the sake of extreme caution.

Since the news broke, a number of experts have come forward to extinguish alarm surrounding vaccination, including Anthony Fauci, the director of the U.S. National Institute of Allergy and Infectious Diseases and the chief medical advisor to the president of the US.

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Can it be treated?

Given that these rare blood clots are different from the typical blood clots, experts advise against self-treating them

Peter Marks, in the press conference advised against using a common blood thinner, heparin, as they could "cause tremendous harm, or the outcome can be fatal."

Instead, experts in the US as well as in the Europe suggest seeking medical attention in case you experience any of the related symptoms associated with the condition.

Marks goes on to talk about how the rare combination of side effects would mean the patients would need individualised treatments.

What are some symptoms you should look out for?

Johnson & Johnson in their statement has advised anyone who has received their vaccine and developed the following symptoms within three weeks after vaccination to contact their health care provider.

  • Severe headache

  • Abdominal pain

  • Leg pain

  • Shortness of breath

For the AstraZeneca Vaccine:

Apart from the already mentioned symptoms, the European Medical Agency (EMA) has also advised seeking immediate medical assistance in case you experience:

  • Chest pain

  • Swelling in your leg

  • Persistent abdominal (belly) pain

  • Neurological symptoms, including blurred vision

  • Tiny blood spots under the skin beyond the site of injection

How will the decision impact the fight against COVID-19?

The move to halt the use of the Johnson & Johnson vaccine could result in a major setback for the vaccination efforts in the US at a time when the country to looking to slowly open up and come out of lockdown, and simultaneously some states are facing a rise in cases.

This could, along with the controversy surrounding the AstraZeneca vaccine, also deepen the problem of vaccine hesitancy, not just in the US but across the world.

(Written with inputs from The New York Times, Business Insider and IANS)

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