Britain on Friday approved the use of the single shot Johnson & Johnson coronavirus vaccine, the Medicines and Healthcare products Regulatory Agency (MHRA) announced.
"This is a further boost to the UK's hugely successful vaccination programme, which has already saved over 13,000 lives, and means that we now have four safe and effective vaccines approved to help protect people from this awful virus," said Health Secretary Matt Hancock.
The government hopes the single-dose jab "will play an important role in the months to come", he added, as young people come forward for their vaccinations amid concern over the rise of the so-called Indian variant.
Britain has ordered 20 million doses of the vaccine.
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
The European Medicines Agency said in April that a warning about unusual blood clots with low blood platelet count should be added to its product information following cases in the United States.
The vaccine was found to be 72 percent effective in preventing moderate to severe coronavirus infection, according to a US trial.
Britain has administered more than 62 million shots so far, mainly using the Pfizer and AstraZeneca vaccines. It has also approved the use of the Moderna vaccine.