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Explained: Pfizer Covid-19 vaccine 90% effective, what is the status of other shots?

Coronavirus (Covid-19) vaccine: Shortly after Pfizer's announcement, Russia's Health Ministry said its Sputnik V vaccine was more than 90% effective against the novel coronavirus

Written by Abhishek De , Edited by Explained Desk | New Delhi |
Updated: November 12, 2020 9:53:49 am
Women walk past a graffiti amid the spread of the coronavirus disease (Covid-19) in New Delhi (Express Photo By Amit Mehra)

US drugmaker Pfizer Inc has stolen a march in Covid-19 vaccine development by becoming the first company to release preliminary data showing that their shot worked in late-stage clinical trials. Shortly, Russia’s Health Ministry also said its Sputnik V vaccine was more than 90 per cent effective against the novel coronavirus. Vaccine candidates by Moderna Inc, Britain-based AstraZeneca-Oxford University and Johnson & Johnson are also hot on the heels and are likely to apply for emergency authorisation this year itself.

The vaccines of many of the leading candidates are based on new, largely unproven techniques like messenger RNA (mRNA) technology or inactivated cold virus platforms. According to the World Health Organization (WHO), more than 150 Covid-19 vaccines are presently in development, with around 44 candidates in clinical trials and 11 undergoing late-stage testing.

Here is a status check of the Covid-19 vaccine frontrunners:

Pfizer coronavirus vaccine

Pfizer and its German partner BioNTech said on Monday their experimental vaccine was more than 90 per cent effective in preventing Covid-19 based on initial data from its Phase III trials. The analysis evaluated 94 Covid-19 infections among the trial’s 43,538 participants.

So far, no serious safety concerns have been found of the BNT162b2 candidate and Pfizer is expected to seek US authorisation for emergency use of the vaccine for people aged 16 to 85. To apply for EUA, the firm will need two months of safety data from about half the study’s nearly 44,000 participants, which is expected late this month.

The findings hold promise since the efficacy rate of the Pfizer vaccine, which uses messenger RNA (mRNA) technology, is well above the 50 per cent effectiveness mandated by the US Food and Drug Administration for a coronavirus vaccine. Moreover, BioNTech’s co-founder and chief executive said the protective effect of the vaccine candidate would last for at least a year.

Early phase clinical trials, published in the journal Nature, had said the Pfizer vaccine induced a “robust” immune response in healthy adults aged 18-55 years. Pfizer said it expects to produce up to 1.3 billion doses of the vaccine in 2021.

Hours after the Pfizer announcement, Russia, which became the first country to approve a Covid-19 vaccine way back in August, claimed its Sputnik V vaccine was more than 90 per cent effective based on data collated from vaccinations on the public rather than from its ongoing Phase III trial. Russia has said it would publish preliminary results of the ongoing large-scale human trials this month. It is testing the Sputnik V vaccine on 40,000 people in Moscow. 📣 Express Explained is now on Telegram

Moderna Inc coronavirus vaccine

Moderna Inc is expected to be next after Pfizer to submit interim results of its mRNA-1273 vaccine trials in November. Last week, the firm completed enrollment for its 30,000-participant Phase III trials. Moderna CEO Stephane Bancel said the firm was “actively preparing for the launch” of its vaccine candidate.

Moderna has announced that it would seek emergency-use authorisation for its vaccine candidate in high-risk groups if interim assessment showed it to be atleast 70 per cent effective. In a bid for a faster approval, Moderna has already begun sharing rolling data submission of its vaccine with the UK’s health regulator. Moderna is eyeing to produce 20 million doses of its experimental vaccine by the end of the year.

An RT-PCR test being conducted at New Delhi’s Trilokpuri (Express photo)

Oxford-AstraZeneca coronavirus vaccine

Britain-based AstraZeneca Plc, which has developed a vaccine candidate with the University of Oxford, is expected to release data of its late-stage clinical trial in November or December. The ChAdOx1 vaccine (also christened AZD1222 and Covishield in India) is made from a weakened version of a common cold adenovirus that causes infections in chimpanzees.

Oxford vaccine trial chief investigator Andrew Pollard said there was a small chance of the ChAdOx1 shot being deployed before Christmas, with the UK’s health regulator starting rolling review of the candidate this month. Rolling reviews allow drug regulators to see clinical data in real time so that approvals can be granted more quickly.

In October, AstraZeneca said the vaccine candidate “has produced a robust immune response in older adults and the elderly, those at highest risk of severe illness”. The vaccine also triggers lower adverse responses among the elderly, it said.

Coming to India, the Serum Institute of India (SII), which is conducting Phase 2/3 trials of the vaccine, said no safety concerns were reported so far, with the first batch of 100 million doses available by the second or third quarter of 2021. “Preliminary results have shown that there are no immediate concerns pertaining to the Covishield vaccine. So far, thousands of people have had it in India and abroad with no safety concerns,” SII’s CEO Adar Poonawalla said.

Johnson & Johnson coronavirus vaccine

Johnson & Johnson, which has resumed late-stage trials of its single-shot JNJ-78436735 vaccine in the United States following a halt due to safety concerns, said it was on track to deliver late-stage clinical trial data this year. Last week, the company indicated its plans to start testing its vaccine in youths aged 12 to 18.

“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 a virtual meeting of the US Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices, Reuters reported.

The remarks come after experts highlighted that the vaccines themselves could trigger a rare, life-threatening condition called Multisystem Inflammatory Syndrome in some children. J&J is at present testing the vaccine, which uses a modified adenovirus like the Oxford shot, in adults in a 60,000-volunteer Phase III study in late September. The firm has said that first batches of its candidate could be available as soon as January.

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