India has ramped up its coronavirus vaccine production amid warnings of a third wave.
India has ramped up its coronavirus vaccine production amid warnings of a third wave.
It has approved Johnson & Johnson's single-dose vaccine for emergency use.
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 - Johnson & Johnson said it was too early to give a delivery timeline.
India has so far given more than 500 million doses of three approved vaccines - Covishield, Covaxin and Russia's Sputnik V.
Johnson & Johnson's jab is the second foreign vaccine to be granted emergency use authorisation in India. This is under a new policy that doesn't require manufacturers to conduct local clinical trials if the vaccine has already been approved by the WHO or regulators in the United States, EU, UK and Japan.
In June, the federal government gave approval to Indian pharma company Cipla to import Moderna vaccine - it has shown nearly 95% efficacy. But jabs are yet to arrive as the company is locked in a tussle with India's federal government - Moderna wants legal protection against claims arising from using the vaccines (which no vaccine maker in India has at the moment) and India has refused so far.
India has reported nearly 32 million Covid cases, second only to the United States, which has reported more than 35 million cases.
Daily case counts have fallen sharply from a high of 400,000 at the peak of the second wave, but they still average around 30,000 to 40,000. And experts have warned that a third wave of infections is inevitable.
The country is also only the third in the world to record more than 400,000 deaths - behind the US and Brazil.
The government aims to vaccinate all Indians by the end of this year, but the drive has been hobbled by slow pace, shortage of doses and vaccine hesitancy.
About 11% of the people have been fully vaccinated since the beginning of the drive in January.
To make up for lost time, the government is now accelerating vaccine production and procurement.
It is 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.
The government has also ordered 300 million doses of another vaccine from Indian firm Biological E.
Last September, US pharmaceutical firm Novavax signed a deal with the SII to produce 2 billion doses of the vaccine.
SII's chief executive officer Adar Poonwalla has said he hoped to launch the vaccine, known as Covovax in India, by September.
He said clinical trials of the vaccine are likely to conclude by November, but SII can apply for a licence before its completion on the basis of global data of the trial.
The Novavax jab, which is given in two doses, was shown to be 91% effective among volunteers at high risk of severe infection and 100% effective in preventing moderate and severe cases of Covid-19 in the US trials.
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.
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.
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.
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.
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.
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.
The other candidates which are in different stages of trials in India to test safety and efficacy include:
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.
By BBC Health News