Last Updated : Nov 16, 2020 11:11 AM IST

Johnson & Johnson starts two-dose trial of its COVID-19 vaccine candidate

The US drugmaker plans to enrol up to 30,000 participants for the study and run it in parallel with a one-dose trial with as many as 60,000 volunteers that began in September.

Representative image
Representative image

Johnson & Johnson launched a new large-scale late-stage trial on November 16 to test a two-dose regimen of its experimental COVID-19 vaccine and evaluate potential incremental benefits for the duration of protection with a second dose.

The US drugmaker plans to enrol up to 30,000 participants for the study and run it in parallel with a one-dose trial with as many as 60,000 volunteers that began in September.

The UK arm of the study is aiming to recruit 6,000 participants and the rest will join from other countries with a high incidence of COVID-19 cases such as the United States, Belgium, Colombia, France, Germany, the Philippines, South Africa and Spain, it said.

They will be given a first dose of either a placebo or the experimental shot, currently called Ad26COV2, followed by a second dose or placebo 57 days later, said Saul Faust, a professor of paediatric immunology and infectious diseases who is co-leading the trial at University Hospital Southampton.

COVID-19 Vaccine

Frequently Asked Questions

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How does a vaccine work?

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.

How many types of vaccines are there?

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.

What does it take to develop a vaccine of this kind?

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.

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The trial follows positive interim results from the company’s ongoing early to mid stage clinical study that showed a single dose of its vaccine candidate induced a robust immune response and was generally well-tolerated.

"The study will assess efficacy of the investigational vaccine after both the first and second dose to evaluate protection against the virus and potential incremental benefits for duration of protection with a second dose," J&J said in a statement.

Rival drugmakers Pfizer and BioNtech said last week that their potential COVID-19 shot showed more than 90 percent efficacy in interim data from a late-stage trial, boosting hopes that vaccines against the pandemic disease may be ready for use soon.

While the Pfizer-BioNtech vaccine uses a new technology known as messenger RNA, J&J’s uses a cold virus to deliver genetic material from the coronavirus into the body to prompt an immune response.

The platform, called AdVac, is also used in an Ebola vaccine that was approved earlier this year.

"It’s really important that we pursue trials of many different vaccines from many different manufacturers and be able then to ensure the supply both to the UK and global population," Faust told reporters at a briefing.

Recruitment into the study will complete in March 2021 and the trial will last for 12 months.

Follow our full coverage on COVID-19 here.
First Published on Nov 16, 2020 11:11 am