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EXPLAINED: What Is Guillain-Barre Syndrome? Why J&J Shot Has Been Linked To The Disorder

Representational image of J&J vaccine. Reuters

Representational image of J&J vaccine. Reuters

What is The Guillain-Barre syndrome, which has been reported in some J&J vax recipients and what does it mean for the one-dose Covid-19 shot?

Cases of a rare neurological disorder have emerged in the US among people who were vaccinated with the Covid-19 shot made by Johnson and Johnson (J&J), prompting the country’s drug regulator to issue a warning regarding the product. The vaccine stands apart as the only single-shot dose and is also relatively easy to store and transport, meaning that poorer countries have shown an interest in using it for their inoculation drives. India has shown an interest in vaccines made in the US, but the J&J shot is yet to receive approval from the country’s health authorities. Here’s the latest on the J&J shot.

What’s The Risk That Has Been Flagged With The J&J Shot?

The US Food & Drug Administration (FDA) has reportedly identified 100 cases of the Guillain-Barre syndrome (GBS) among people who were vaccinated with the J&J shot in that country. The company was informed that preliminary reports show 95 of the cases were classified as serious and required hospitalisation and there was one death. Close to 13 lakh people have received the J&J shot in the US.

The US diseases watchdog, the Centre for Disease Control and Prevention (CDC) said that most of the GBS cases were in men and many of them were aged over 50 years or older. J&J added in a statement that most of the GBS cases emerged within 42 days, or 6 weeks, after vaccination.

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The FDA said that the chances of getting GBS post vaccination were “very low" but advised J&J vaccine recipients to seek medical attention if they show symptoms like weakness or tingling sensations or have difficulty walking or difficulty with facial movements after receiving their shot.

J&J said that it shares “any adverse event report" about individuals receiving its single-shot vaccine with US authorities, the European Medicines Agency, the World Health Organisation and other health authorities around the world where the vaccine is authorised.

What Is The Guillain-Barre Syndrome?

The US-based health not-for-profit Mayo Clinic describes the Guillain-Barre (gee-YAH-buh-RAY) syndrome as a “rare disorder" in which the body’s immune system attacks the nerves. Weakness and tingling in the extremities are the usual symptoms, though they can quickly spread, “eventually paralyzing your whole body". It adds that most people with the condition must be hospitalised.

Although it is not known what exactly causes GBS, “two-thirds of patients report symptoms of an infection in the six weeks preceding", including respiratory or a gastrointestinal infection. There is no cure for the disorder but “several treatments can ease symptoms and reduce the duration of the illness". Most patients fully recover from the disease, whose mortality rate ranges between 4-7 per cent.

J&J said that people who receive its vaccine should “seek medical attention right away" if they develop any symptom like “weakness or tingling sensations, especially in the legs or arms, that’s worsening and spreading to other parts of the body, difficulty walking, difficulty with facial movements, including speaking, chewing, or swallowing, double vision or inability to move eyes,

difficulty with bladder control or bowel function".

It is reported that GBS has in the past been observed during vaccination campaigns against swine flu in the US in 1976, and when the H1N1 flu pandemic had hit in 2009.

What kind of vaccine is J&J?

The J&J shot is built on the viral vector platform, which is used by some of the most common and widely administered vaccines against the novel coronavirus, which causes the Covid-19 disease.

The key principle on which any vaccine works is to introduce the immune system to the pathogen that causes the disease so that it can train itself to recognise the same pathogen in the future and counter it.

For a viral vector vaccine, scientists use a modified, and harmless, version of a different virus (which is the vector, or carrier) to insert molecular instructions into human cells. In the case of Covid-19 vaccines, the human cells read this instruction to produce the spike protein of the novel coronavirus — which it uses to infect humans. Once the body starts producing the spike protein, the immune system is activated and it gets to work manufacturing antibodies against the virus.

The Oxford-AstraZeneca vaccine, which is being used in India as Covishield, and the Russian-made Sputnik V vaccine, too, are viral vector shots. European regulators had last week reportedly recommended a warning along the lines of that for the J&J shot for the AstraZeneca vaccine.

What Have Been Issues Affecting J&J Vaccine?

The latest FDA warning represents a fresh setback for the J&J shot after it became the third vaccine cleared for emergency launch in the US earlier this year. Right at the outset, the FDA found grave issues at the key production site for the vaccine in the US and it made the company throw out millions of doses citing unsatisfactory standards. The New York Times in June, in fact, reported that the US authorities had asked the company to junk 60 million doses.

Then there were issues with blood clots. In April, the US called a pause on vaccinations with the J&J shot as health authorities investigated cases of rare blood clots linked to it. After the CDC found 15 cases of the clots in nearly 8 million people who got the J&J vaccine, it decided to lift the suspension but added a warning that younger women may run a slight risk of the severe side effect.

Authorities in the European Union (EU), too, have identified blood clots as a “very rare" side effect of the J&J vaccine but reports in April said it was ruled that the benefits of the vaccine outweighed the risks.

Has The J&J Shot Come To India?

The J&J vaccine has shown an efficacy rate of up to 72 per cent in trials and can be stored for up to 4.5 months at moderately cold temperatures of 2–8 degrees Celsius. That would make it a suitable candidate for vaccinations in India given the logistical ease of delivering a one-shot vaccine that does not require ultra cold storage. But though the Centre has cleared the decks for vaccines that are being used in the US to launch in India, J&J is still reportedly in talks to roll out its shot in the country.

Reports last week said government officials were pursuing with company officials the release of the J&J shot in India and that it could be manufactured domestically with the Hyderabad-based Biological E having entered into an agreement with J&J. India has so far granted emergency use nod to four vaccines — Covishield, the indigenously made Covaxin, Sputnik V and the US-made Moderna.

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first published:July 13, 2021, 10:59 IST