A box of Johnson & Johnson’s Janssen COVID-19 vaccine doses are pictured at Grubb’s Pharmacy on Capitol Hill on Monday, April 12, 2021.

Tom Williams | CQ-Roll Call, Inc. | Getty Images

LONDON — The U.K.’s medicines regulator on Friday approved Janssen’s single-dose Covid-19 vaccine for use.

Britain’s Medicines and Healthcare products Regulatory Agency (MHRA) said in a statement that doses were expected to be available in the U.K. later this year.

The British government’s Vaccine Taskforce has secured 20 million doses to be rolled out across the U.K. Initially, it had secured 30 million doses but amended the order as the vaccination program continues at what the government described as an “unprecedented scale and pace.”

Earlier this year, the vaccine was found to be 67% effective in preventing infections and 85% effective in preventing severe cases of Covid-19 and hospitalizations. Janssen is a pharmaceutical company of Johnson & Johnson.

U.K. Health Minister Matt Hancock said on Friday that the approval of the Janssen vaccine would further boost the country’s “hugely successful” vaccination program.

“As Janssen is a single-dose vaccine, it will play an important role in the months to come as we redouble our efforts to encourage everyone to get their jabs and potentially begin a booster programme later this year,” he said in a statement.

The vaccine can be stored in refrigerators between two to eight degrees Celsius (35.6 to 46.4 degrees Fahrenheit), making its storage and transportation easier than some alternative vaccines.

The Janssen vaccine is the fourth to be authorized for use in the U.K., joining the Oxford-AstraZeneca, PfizerBioNTech and Moderna alternatives in being approved by the MHRA.

The Vaccine Taskforce has secured early access to more than 500 million doses of eight vaccine candidates, including those being developed by Novavax, GlaxoSmithKline and CureVac, as well as the four the U.K. has already approved for use.

The government said it was in regular contact with the manufacturers of the vaccine to help optimize supply and prepare for a possible vaccination booster program later in 2021.

Janssen’s Covid-19 vaccine is currently involved in a government study to assess the safety and efficacy of giving people a third dose to boost their immunity to the virus. The Oxford-AstraZeneca, Pfizer-BioNTech and Moderna vaccines all require two doses for patients to reach optimum immunity.

The U.K.’s Joint Committee on Vaccination and Immunisation will submit updated advice for use of the Janssen vaccine before it is rolled out.

Janssen’s vaccine is already being used elsewhere, including in the U.S. and the European Union.

There have been concerns among health authorities about possible links between the vaccine and rare blood clots, but regulators have said the benefits of receiving the vaccine outweigh the risks.

Janssen is exploring the possibility of a two-dose program for its vaccine, according to the U.K.’s Department for Health and Social Care.

The U.K. government has set a target of offering all adults in the country a Covid-19 vaccine by the end of July, which it says it is on track to achieve.

More than 62.6 million vaccines had been given in the U.K. by May 26, with 73% of the adult population having received their first dose. Almost half of British adults have been fully vaccinated with both doses.

Read More