ZyCoV-D vaccine safe and effective for adolescents, says expert

Reactogenicity is lesser than other vaccines, says Dr Arora of National COVID-19 Task Force

August 28, 2021 08:42 pm | Updated 08:43 pm IST

Dr. N.K. Arora, a senior member of National COVID-19 Task Force and Advisor, national AEFI committee, speaks to The Hindu about the ZyCoV-D vaccine — the world’s first plasmid DNA vaccine for human use — and how it could be the beginning of a vaccine revolution. He also explains why, with schools reopening, there is a need to follow COVID-appropriate protocols religiously to prevent a spike in cases.

“We need to avoid crowding in the classes. So, schools have to devise strategies for that; wearing of masks must be monitored and teachers and other school staff have to lead particularly by the use of masks,” he said in the interview.


How is Zydus-Cadila’s ZyCoV-D vaccine different from the existing vaccines, especially the m-RNA vaccines?

ZyCoV-D vaccine is the world’s first plasmid DNA vaccine for human use. DNA, or Deoxyribonucleic Acid, contains the genetic code of various components of an organism. For the vaccine, the part of the COVID virus that helps it enter the cell and cause disease is coded. When the vaccine is injected into the human body, it produces that particular part of the virus and stimulates the immune system to generate antibodies and T-cells immunity against the virus.

This DNA piece is enclosed by a membrane called plasmid, and it disintegrates after it has completed its action. This DNA is a lab-made structure and is unable to interfere with the genetic composition of humans. The m-RNA vaccines are also made with the same principle. These again are lab-made structures and not obtained from the actual virus.

Is the vaccine approved for children?

Any new vaccine is first tested on adults and then on children; this holds true for all the currently used paediatric vaccines. Similarly, the COVID-19 vaccines, for example, Covishield, Covaxin and Sputnik, have been used in adults. Covaxin is now being tested in children 2-18 years old. The key assessment criteria are the safety of the vaccines and their immunogenic capacity in children. ZyCoV-D, along with adults, has also been tested in adolescents between 12 and 17 years of age. Now, we have the first approved, safe and effective vaccines for adolescents in India.

Is this vaccine safer than the previous one?

The Phase I, II and III trials of the ZyCoV-D vaccine demonstrated its safety in all age groups. In fact, the reactogenicity of the vaccine, that is, fever, pain, feeling of illness is much lesser than the other currently used vaccines in India.

Like vaccination for adults, will there be a prioritisation in the paediatric age group as well?

Prioritisation of adults was based on occupation, co-morbidities and age. Two criteria were used for the prioritisation: exposure probability and risk of severe disease and death. In children, COVID-19 is mostly asymptomatic or mild; severe disease and death are rare. Like for adults, for children too, the priority will be given to those with co-morbidities such as heart disease, chronic kidney, liver, lung diseases and other illnesses that put them comparatively at a higher risk of developing severe disease than healthy children.

Secondly, there are 44 crore children in India, out of them 12 crore are in the 12-17 age group. We intend to prioritise adult immunisation and simultaneously start immunising children with co-morbidities.

When will the vaccine be available for people? What is the current production capacity of this vaccine?

We are expecting to begin inoculating adults and adolescents with co-morbidities by mid-October. For healthy children, COVID-19 vaccination is likely to be launched by the first quarter of 2022. The current production capacity of ZyCoV-D is 1 crore doses per month. It is expected that it will be ramped up to 2-3 crore doses a month in the coming months. We need to understand that the DNA vaccine production line is a slow process and might require technology transfer to other companies as well.

Tell us about the dosage and intervals between doses?

This is a three-dose vaccine, given with a needleless device called jet inject/Pharmajet, which is also painless. Every dose is 2 mg dose, split into two parts administered at two separate sites to get a maximum immune response. All three doses will be given in the same manner at an interval of four weeks each. The vaccine is associated with negligible side-effects and the recipient does not feel any pain or discomfort at the injected site. Even fever or fatigue is uncommon post-vaccination.

Currently, the vaccine is available only in India. This is a totally indigenously produced vaccine. And we are expecting that this technology will transform the vaccine scenario in the country and also globally. We may now be able to develop vaccines for stubborn organisms such as HIV using this technology.

Now that the vaccine for children will soon be available, do you think it will be a good idea to send children to school only after they get vaccinated?

As explained earlier, paediatric vaccination can wait. Based on Indian as well as global data, the risk of severe disease and death are rare in children. However, children can spread infection. Adults have almost 15 times higher risk of death and severe disease compared to children below 18 years. So, if adults around them at home or at school are vaccinated, it will form a protective ring around them. There will be limited virus and disease transmission in that condition.

I strongly feel that parents should send their kids without waiting for COVID-19 vaccine to school for two reasons: one, their risk of developing a severe disease is rare; second, going to school is important for their cognitive, physical and mental development.

Some parents are afraid of sending their children as they fear the third wave. Is the third wave for real?

Personally, I feel that based on the current virus and disease epidemiology, sero-positivity rate and the fact that 90% of the circulating virus is Delta virus, and no new variant of concern has been reported in the past four weeks, it seems we are at the tail-end of the second wave.

The risk of the third wave is there only if people show complacency in following COVID-Appropriate Behaviour, especially during the upcoming festival season; large social gatherings of any kind will be dangerous based on our recent experiences.

We need to follow COVID-Appropriate protocols religiously in the school as well. We need to avoid crowding in the classes. So, schools have to devise strategies for that; wearing of masks must be monitored and teachers and other school staff have to lead particularly by the use of masks.

Children have been confined to homes for the past one-and-a-half years. They have witnessed a lot of disruption in their personal lives during the pandemic. Schools and parents may seek advice from educationists, mental health specialists and psychologists before arriving at a decision.

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