The British government has so far ordered 20 million doses of the vaccine from Janssen, a division of J&J, set to arrive later this year, with the jab having shown 85% effectiveness in preventing severe Covid-related illness during manufacturer Janssen’s trials.

“The Janssen vaccine will be another weapon in our arsenal to beat this pandemic,” vaccine deployment minister, Nadhim Zahawi, said following the approval.

The government has not yet outlined details of who will receive the vaccine, with the Joint Committee on Vaccination and Immunisation (JCVI) set to provide that guidance shortly.

Johnson & Johnson's Janssen jab joins the Oxford-AstraZeneca, Pfizer-BioNTech, and Moderna vaccines in the UK’s inoculation line-up, adding what Health Secretary Matt Hancock called a “further boost” to its “hugely successful” rollout.

Due to the ability to easily store and transport the Johnson & Johnson vaccine, as it can be stored at fridge temperature, it could help to boost the existing vaccination campaign by providing for individuals who can’t travel to inoculation centres.

Janssen’s Covid vaccine had already been approved for use by the European Medicines Agency (EMA), the US' Food and Drug Administration (FDA) and the World Health Organization (WHO), though the EMA is currently in the process of investigating the death of a Belgian woman who'd received the jab.

The rollout of J&J's Janssen jab had previously been paused in America, the EU and South Africa, after reports of rare blood clots in a small number of US recipients. However, after an analysis of the risk-versus-benefit data of the jab, states resumed its usage and the pharma firm proceeded with dose deliveries.