Explained: India approves Johnson & Johnson’s single dose COVID19 vaccine — its efficacy, past controversies
Johnson and Johnson's COVID19 vaccine, named as Janssen, has become the fourth COVID19 vaccine, and the first single-dose vaccine, to be allowed emergency use authorisation in India. How effective is it, what controversies has it faced in the past, details here.
The single dose vaccine can be a major boost to India's vaccination program as it will quickly accelerate the number of people protected against COVID19. Photo: J&J
Union Minister for Health and Family Welfare Mansukh Mandaviya announced today, on August 7, that the single shot COVID19 vaccine Janssen which is manufactured by the pharmaceutical giant Johnson & Johnson has been approved for emergency use vaccination in India.
The Janssen vaccine is the first single-dose vaccine to be allowed in India as the government is still studying data from other countries to assess if a single dose of the Russian Sputnik V ‘light’ vaccine was enough to give protection against COVID19 infection.
The vaccine by Johnson & Johnson is the fifth COVID19 vaccine to be allowed for emergency use in India with the other four being — Covishield by Serum Institute of India, Covaxin by Bharat Biotech, Moderna, and Russia’s Sputnik V.
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How effective is Johnson & Johnson’s vaccine?
The efficacy of the Janssen vaccine has been recorded to be 72 per cent in the United States and 66 per cent globally. The US FDA (Food and Drug Administration) approved the vaccine for its emergency use on February 27.
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The single dose vaccine can be a major boost to India’s vaccination program as it will quickly accelerate the number of people protected against COVID19.
The vaccine uses a different technology than the other two American vaccines (Pfizer and Moderna) which use the mRNA of the virus.
How is Janssen different from other US-made vaccines?
The vaccines like Moderna and Pfizer work by putting an mRNA or the messenger RNA (Ribo nucleic acid) — inside the human body which further instructs the cells to create a spike protein which is identical to the spikes on the surface of SARS-CoV-2 virus. The immune system then detects the new protein and realises that it’s an unknown molecule and begins to produce antibodies against it.
In the event of an actual infection by COVID19, the immune memory remembers the defence mechanism and readily produces anti-bodies to defend the body against the viral invasion.
But Janssen vaccine uses a shell of the virus known as an adenovirus which elicits an immune response.
Past controversies regarding Janssen
Marred by a controversy about the formation of blood clots amongst some of the recipients of the vaccine, the FDA has added a warning about Thrombosis with thrombocytopenia syndrome (TTS) in its emergency use authorisation of the J&J vaccine but has not restricted its use.
The University of California, in its article on the Janssen vaccine underlines that as of May 16, 16 cases of these blood clots have been reported among a total of about 8 million people who received the J&J vaccine.
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“The unusual condition is known as thrombosis (blood clot) with thrombocytopenia (low platelet count), or TTS, which normally occurs at a rate of about one in a million per year in the general population. Among those who have received the J&J vaccine, the rate is about two in a million. That is on par with the rate of anaphylaxis, a severe allergic reaction, that has been reported for the mRNA vaccines, about 2.5 per million,” it stated.