Johnson & Johnson plans to start testing its experimental COVID-19 vaccine in youths aged 12 to 18 as soon as possible, and the company’s previous experience with the same technology in a vaccine successfully used in children could give it a leg up with regulators.

“We plan to go into children as soon as we possibly can, but very carefully in terms of safety,” J&J’s Dr Jerry Sadoff told at a virtual meeting of the US Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices.

Depending on safety and other factors, the company plans to test in even younger children afterwards, said Sadoff, a vaccine research scientist at J&J’s Janssen unit, without giving a timeline.

J&J said in a statement that it is currently in discussions with regulators and partners regarding the inclusion of the paediatric population in its trials.

The US Food and Drug Administration has said it is important for drugmakers to test their vaccines in children. Some doctors have raised concerns that the vaccines themselves could trigger a rare, life-threatening condition called Multisystem Inflammatory Syndrome in some children.

Pfizer has already begun testing the COVID-19 vaccine it is developing with Germany’s BioNTech in children as young as 12. Their vaccine uses messenger RNA (mRNA), a new technology that has yet to produce an approved vaccine.

J&J’s uses a cold virus to deliver coronavirus genetic material in order to spur an immune response. The platform – called AdVac – is used in a vaccine for Ebola that was approved in Europe earlier this year and used on more than 100,000 people, including infants, children, and pregnant women.

The technology’s history of safety should be important to regulators, said Dr Paul Spearman, director of the infectious diseases division of Cincinnati Children’s Hospital.

“Most of the toxicities are going to come from the platform and not from putting a different insert into the platform, Spearman said. So replacing the Ebola genetic material with that of the novel coronavirus “is unlikely to give you major issues,” he added.

J&J started testing the vaccine in adults in a 60,000-volunteer Phase III study in late September. It had to pause the trial earlier this month because of a serious medical event in one participant. The study resumed last week.