On 25 December, Bharat Biotech's COVID vaccine, Covaxin, was approved for use in children over the age of 12 by India's drugs regulatory body, the Drugs Controller General of India (DCGI).

Shortly after the announcement, Prime Minister Narendra Modi addressed the nations stating that COVID vaccines would be made available to children between the ages of 15 and 18 years starting 3 January.

A couple of days later, the Union Health Ministry announced that only Covaxin would be made available to children at the moment.

How much do we know about the Covaxin COVID vaccine, and its clinical trials on children below the age of 18?

The DCGI granted an Emergency Use Authorisation (EUA) for the use of Covaxin in children based on a recommendation made by the Subject Expert Committee (SEC) of the Central Drugs Standard Control Organisation (CDSCO).

Bharat Biotech reportedly submitted the results of phase 3 clinical trials on 2 to 18-year-old kids to the in August for review, based on which a subject expert committee recommended rolling out the vaccine for the same age group in October.

A preprint version of the phase 2/3 trials released on 30 December finds the vaccine to be demonstrating 'robust safety and immunogenicity in 2-18 Volunteers.'

Here are some key points that we know about the phase 2/3 clinical trial.

• The phase 2/3 trial was an open-Label, multi-centre Study.

• The trials were conducted between June 2021 to September 2021.

• 525 eligible participants were enrolled and divided into three groups based on their age, in an age descending way.

• As is the practice with trials on children, this study did not have a control arm.

• All the children in all three groups were administered two 0.5mL doses of the vaccine (same dosage as adults).

The study aimed to gauge the safety and efficacy of the vaccine as well as assess the neutralising antibodies elicited post vaccination.

They did this by testing the immune response of the children before they receive the vaccine and then comparing this to the results after they receive the vaccine.

What did the study find?

• Antibody response after vaccination was found to be more robust in children than in adults.

  Neutralizing antibodies in children on an average was found to be 1.7 times higher than in adults.

• No serious adverse event, or death was reported.

• Soreness at the site of the injection was the most common side effect reported.

• No cases of myocarditis or blood clots were reported.

It is also unknown why the DCGI decided to keep 12 years as the cut off age while granting the EUA, and furthermore why the cut off age for administering vaccines was set at 15 years by the government.

Many experts in India have expressed their skepticism when it comes to giving COVID vaccines to children, citing the lack of data to prove its immediate need.

Speaking to The Quint, eminent virologist Dr Gagandeep Kang said, "we've got 60 percent coverage among children who have not received the vaccine at all. Do we really need to vaccinate kids who may already have had exposure?"

It is also interesting that Covaxin, unlike other COVID-19 vaccines that have been approved for use in children, has the same dosage of two 0.5ml shots given with an interval of 28 days for both adults and children.

About this Dr Kang said, "If the goal is to maximise the immune response in children, its not really a problem to give children the same dose of an inactivated vaccine."

"Just because the vaccines have been approved doesn't mean that w will be using them in children in the same way as we did in the adults."

The approval opens the door for immunocompromised and high risk children to get vaccinated.

She went on to reiterate, "we should be aiming at making sure we have a very high coverage of the vulnerable populations and then think about vaccinating others.