Vials of Johnson & Johnson’s Janssen COVID-19 vaccine lie in a tray. Photo: Johnson & Johnson/Handout via Reuters
Bengaluru: The US Centres for Disease Control and Prevention (CDC) as well as the Food and Drug Administration (FDA) have recommended that American refrain from distributing the Johnson & Johnson vaccine after reports of six rare but potentially life-threatening blood clots.
STAT News reported that the events are similar to those following administration of the AstraZeneca vaccine in the EU and “to an event that occurred during J&J’s US-based clinical trial”.
There, medical authorities in some countries – including Germany and France – paused rollouts of this vaccine to check for a causal link between inoculation and the clots.
The rollout resumed after the European Medicines Agency as well as the WHO insisted that the vaccine’s benefits outweighed its risks.
The two bodies’ recommendation is not binding on state authorities. STAT also said that the CDC’s Advisory Committee on Immunisation Practices will meet on Wednesday to review the data and determine the next course of action.
The Johnson & Johnson vaccine is a single-dose viral vector vaccine. This means a harmless virus (not SARS-CoV-2) – the viral vector – will first enter a human cell. There, it will hijack the cell’s resources to manufacture a similarly harmless piece of the novel coronavirus’s’ spike protein. When the cell displays this spike protein on its surface, it draws the attention of the body’s immune system.
Both the Johnson & Johnson and the AstraZeneca vaccines (called Covishield in India) use the weakened form of an adenovirus that causes cold among chimpanzees as the viral vector. Viral vector vaccines’ advantage is that they are relatively cheap to produce in large quantities. On the flip side, these vaccines may not be very effective if they use a viral vector the human body has been exposed to before.
NDTV quoted the FDA saying the US has thus far administered the vaccine to 6.8 million people and that, “right now, these adverse events appear to be extremely rare.” The AstraZeneca shot is not yet approved for use in the US.
In clinical trials, researchers found the Johnson & Johnson vaccine to be 66% efficacious at preventing moderate COVID-19 and 85% at preventing severe COVID-19.
The vaccine it is producing and selling was originally developed by researchers at a Belgian biotechnology company called Janssen Vaccines. This organisation’s parent company is Janssen Pharmaceuticals, which itself is a subsidiary of Johnson & Johnson.
On April 13, the Indian government announced that it will stop asking foreign vaccine-makers for bridging trials in India before they can sell their vaccines in the country, in an effort to improve access to vaccines in the face of a staggering second wave.
To this end, “we hope and we invite vaccine-makers such as Pfizer, Moderna, Johnson & Johnson and others … to be ready to come to India as early as possible,” Vinod K. Paul, a senior government health official, said at a press conference.