This post was originally published on this site
India has given a boost to its vaccination programme by approving its first vaccine for those under 18.
The three-dose ZyCoV-D vaccine prevented symptomatic disease in 66% of those vaccinated, according to an interim study quoted by the vaccine maker Cadila Healthcare.
This is also the first time, the firm claimed, a Covid-19 vaccine had been tested in young people in India. The jab was found to be “safe and very well-tolerated” in this age group.
India has so far given more than 570 million doses of three previously approved vaccines – Covishield, Covaxin and Sputnik V. The government aims to vaccinate all Indians by the end of this year.
About 13% of eligible adults have been fully vaccinated and 47% have received at least one shot since the beginning of the drive in January.
India has reported more than 32 million Covid cases, second only to the US. The country is also only the third in the world to record more than 400,000 deaths – behind the US and Brazil.
How does the new vaccine work?
The ZyCoV-D vaccine is also the world’s first DNA vaccine against Covid-19.
Like other vaccines, a DNA vaccine, once administered, teaches the body’s immune system to fight the real virus.
ZyCoV-D uses plasmids – or small rings of DNA that contain genetic information – to deliver the jab between two layers of the skin.
ZyCov-D is also India’s first needle-free Covid-19 jab.
It is administered with a disposable needle-free injector, which uses a narrow stream of the fluid to penetrate the skin and deliver the jab to the proper tissue.
Cadila Healthcare said it had conducted the largest clinical trial for the vaccine in India so far, involving 28,000 volunteers in more than 50 centres.
The key third phase of clinical trials was conducted at the peak of the deadly second wave of the virus. The vaccine maker believes this reaffirmed the jab’s “efficacy against the mutant strains”, especially the highly infectious Delta variant.
Previous DNA vaccines have worked well in animals but not humans.
The challenge, say scientists, was how to push the plasmid DNA into the human cell so that it gives a durable immune response.
Dr Jeremy Kamil, a virologist at Louisiana State University Health Sciences Center in Shreveport, told the BBC that it was imperative that the efficacy data of the vaccine “be vetted independently”.
The other potential drawback is that ZyCoV-D requires three doses, instead of two as is the case with the other two candidates being used in India. The vaccine maker says it is evaluating at a two-dose jab.
The firm plans to make up to 120 million doses of India’s second home-grown vaccine every year. It is expected to be made available in September.
What are other vaccines that India has recently approved?
India has also approved Johnson & Johnson’s single-dose vaccine for emergency use. The jab is the second foreign vaccine to be granted emergency use authorisation in India.
The vaccine, which has shown 85% efficacy, will be introduced in India through a supply agreement with homegrown vaccine maker Biological E.
It’s still unclear when the vaccine will be available for use in India.
In June, the federal government gave approval to Indian pharma company Cipla to import Moderna vaccine – it has shown nearly 95% efficacy.
But some reports say the vaccine is not likely to be made available in India until 2022 because of a “supply crunch”.
The government is also preparing to use a local version of Novavax vaccine, which will be produced by the Serum Institute of India (SII). The vaccine was more than 90% effective in a late-stage US-based clinical trial, according to the company.
SII’s CEO Adar Poonwalla has said he hoped to launch the vaccine, known as Covovax in India, by September.
What about the Biological E vaccine?
The government has placed an order for 300 million doses of a coronavirus vaccine from Biological E – it was developed in collaboration with US-based Dynavax and Baylor College of Medicine.
The $206m (£145m) order is the first India has signed for a jab that has not received emergency approval.
The unnamed vaccine is in the key third phase of clinical trials – the vaccine is given to thousands of people and tested for efficacy and safety – after showing “promising results” in the first two phases, the government said in a statement.
What do we know about Sputnik V?
The vaccine, developed by Moscow’s Gamaleya Institute, initially generated some controversy after being rolled out before the final trial data had been released. But scientists say its benefits have now been demonstrated.
It uses a cold-type virus, engineered to be harmless, as a carrier to deliver a small fragment of the coronavirus to the body. After being vaccinated, the body starts to produce antibodies especially tailored to the virus.
It can be stored at temperatures of between 2 and 8C degrees (a standard fridge is roughly 3-5C degrees) making it easier to transport and store.
But unlike other similar jabs, the Sputnik jab uses two slightly different versions of the vaccine for the first and the second dose – given 21 days apart.
They both target the coronavirus’s distinctive “spike”, but use different vectors – the neutralised virus that carries the spike to the body.
The idea is that using two different formulas boosts the immune system even more than using the same version twice – and may give longer-lasting protection.
India received its first batch of 125 million doses of the vaccine in May. The Russian Direct Investment Fund (RDIF), which is marketing the vaccine, has signed deals to produce more than 750 million doses of the vaccine with six more domestic vaccine makers, according to reports.
Sputnik V has been approved so far in 60 countries, including Argentina, Palestinian territories, Venezuela, Hungary, UAE and Iran.
What do we know about Covaxin?
Covaxin is an inactivated vaccine which means that it is made up of killed coronaviruses, making it safe to be injected into the body.
Bharat Biotech, a 24-year-old vaccine maker with a portfolio of 16 vaccines and exports to 123 countries, used a sample of the coronavirus isolated by India’s National Institute of Virology.
When administered, immune cells can still recognise the dead virus, prompting the immune system to make antibodies against the pandemic virus.
The two doses are given four weeks apart. The vaccine can be stored at 2C to 8C.
The vaccine has an efficacy rate of 81%, preliminary data from its phase 3 trial shows.
India’s regulators gave the vaccine emergency approval in January while the third phase of the trial was still underway, sparking scepticism and questions from experts.
What was the controversy around Covaxin?
It all began when the regulator in January said the vaccine had been approved for “restricted use in emergency situations in public interest as an abundant precaution, in clinical trial mode, especially in the context of infection by mutant strains”.
Experts wondered how a vaccine was cleared for emergency use by millions of vulnerable people when its trials were still underway. The All India Drug Action Network at the time said that it was “baffled to understand the scientific logic” to approve “an incompletely studied vaccine”.
Both the manufacturer and drug regulator defended Covaxin, saying it was “safe and provides a robust immune response”.
Bharat Biotech said that Indian clinical trial laws allowed “accelerated” authorisation for use of drugs after the second phase of trials for “unmet medical needs of serious and life-threatening diseases in the country”.
It has promised to make available the full data for third phase of trials in July.
What about Covishield?
The Oxford-AstraZeneca vaccine is being manufactured locally by SII.
The vaccine is made from a weakened version of a common cold virus (known as an adenovirus) from chimpanzees. It has been modified to look more like coronavirus – although it can’t cause illness.
When the vaccine is injected into a patient, it prompts the immune system to start making antibodies and primes it to attack any coronavirus infection.
The jab can be safely stored at temperatures of 2C to 8C, and is administered in two doses given between four and 12 weeks apart.
How effective is Covishield?
International clinical trials of the Oxford-AstraZeneca vaccine showed that when people were given a half dose and then a full dose, effectiveness hit 90%.
But there was not enough clear data to approve the half-dose, full-dose idea.
However, unpublished data suggests that leaving a longer gap between the first and second doses increases the overall effectiveness of the jab – in a sub-group given the vaccine this way it was found to be 70% effective after the first dose.
SII, the Indian maker of the vaccine, says Covishield is “highly effective” and backed by phase III trial data from Brazil and United Kingdom. Clinical trials are a three-phased process to determine whether the vaccine induces good immune responses and whether it causes any unacceptable side-effects.
Are there any other vaccine candidates?
The other candidates which are in different stages of trials in India to test safety and efficacy include:
- ZyCov-Di, being developed by Ahmedabad-based Zydus-Cadila
- HGCO19, India’s first mRNA vaccine made by Pune-based Genova in collaboration with Seattle-based HDT Biotech Corporation, using bits of genetic code to cause an immune response
- A nasal vaccine by Bharat Biotech
Which countries are signing up for India’s vaccines?
India has shipped 66 million doses of vaccines to 95 countries in Latin America, the Caribbean, Asia and Africa. The recipient countries include UK, Canada, Brazil and Mexico.
Both Covishield and Covaxin have been exported – some in the form of “gifts”, others in line with commercial agreements signed between the vaccine makers and the recipient nations, and the rest under the Covax scheme, which is led by the World Health Organization (WHO) and hopes to deliver more than two billion doses to people in 190 countries in less than a year.
But in March, India placed a temporary hold on all exports of the Oxford-AstraZeneca vaccine. The government said rising cases meant domestic demand was expected to pick up and so the doses were needed for India’s own rollout.