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Explained: From efficacy to cost, what you need to know about India’s Covid-19 vaccines

Coronavirus (Covid-19) vaccine: The drug regulator also gave the green light to Cadila Healthcare Ltd to conduct Phase 3 clinical trials of its ZyCoV-D vaccine candidate for Covid-19.

By: Explained Desk | New Delhi |
Updated: January 6, 2021 8:32:03 am
Dry run of Covid-19 vaccination process at Duttabad primary health centre in Saltlake, Kolkata (Express photo by Partha Paul)

Coronavirus (Covid-19) vaccine: India’s fight against Covid-19, which has infected more than 1 crore people and killed 1.5 lakh, received a shot in the arm on Sunday after the Drug Controller General of India (DCGI), the country’s national drug regulator, approved two coronavirus vaccines for restricted emergency use — Serum Institute of India’s Covishield (the Indian variant of the AZD1222 vaccine developed by Oxford University and AstraZeneca) and Bharat Biotech’s Covaxin.

On safety concerns regarding the vaccines, Drugs Controller General of India, VG Somani said, “We will never approve anything if there’s slightest of safety concern. Vaccines are 110 % safe. Some side effects like mild fever, pain & allergy are common for every vaccine.”

Besides, the DCGI also gave the green signal to Cadila Healthcare Ltd to conduct Phase 3 clinical trials of its ZyCoV-D vaccine candidate for Covid-19. The Pfizer vaccine and Russia’s Sputnik-V are likely to be approved for use in India in the coming weeks. The government is now set to embark on one of the largest immunisation programmes, with nearly 3 crore healthcare and frontline workers set to be dosed in the first phase.

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Here is all you need to know about the Covid-19 vaccines approved in India:

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Serum Institute of India’s Covishield vaccine

India on Sunday became the fourth country after the UK, Argentina and El Salvador to approve the coronavirus vaccine developed by Oxford University and AstraZeneca, which is being manufactured in the country by Pune-based Serum Institute. SII has already stockpiled more than 50 million doses of Covishield so far and currently has a capacity to make around 50-60 million doses a month.

Type of vaccine: The ChAdOx1 vaccine (also christened AZD1222) is made from a weakened version of a common cold adenovirus that causes infections in chimpanzees.

Effectiveness: Drugs Controller General of India VG Somani said the overall efficacy of the AstraZeneca/Oxford vaccine was found to be 70.42 per cent — well below vaccines from Pfizer and Moderna, but above the 50 per cent threshold set by many regulators.


“The firm submitted safety, immunogenicity and efficacy data generated on 23,745 participants aged 18 years or older from overseas clinical studies. Data of Phase-2/3 clinical trials on 1,000 participants within the country was also submitted and it was found comparable with the data from the overseas clinical studies,” Somani said.

The vaccine, however, has been plagued by uncertainty about its most effective dosage ever since data published in November showed a half dose followed by a full dose had a 90 per cent success rate while two full shots were 62 per cent effective. In December, citing data from early trials, Oxford said the vaccine had a better immune response when a two full-dose regime was given.

Dosage, protection duration and storage: The Subject Expert Committee (SEC) has recommended the approval of two full doses of the vaccine administered around 4-6 weeks apart. Immune response could last at least a year. The vaccine can be stored at temperatures between 2°C and 8°C.


Pricing: Serum Institute of India has said it would price the vaccine at 440 rupees (about $3) for the government and around Rs 700-800 for the private market.

Ranchi: Health workers show victory sign after the Covid-19 vaccination mock drill and the dry run at a government hospital in Ranchi (PTI)

Bharat Biotech’s Covaxin

Covaxin has been indigenously developed by Hyderabad-based Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR).

Type of vaccine: Covaxin is an “inactivated” vaccine and is made by using particles of the coronavirus that were killed, making them unable to infect or replicate. Injecting particular doses of these particles serves to build immunity by helping the body create antibodies against the dead virus.

Effectiveness: Bharat Biotech’s Covaxin was “safe and provides a robust immune response”, said Drugs Controller General of India VG Somani. The vaccine is yet to complete late-stage human clinical trials in India and no efficacy rate has yet been made public.

“The Phase 1 and Phase 2 clinical trials were conducted on about 800 subjects and the results have demonstrated that the vaccine is safe and provides a robust immune response. The Phase 3 efficacy trial was initiated in India on 25,800 volunteers and till date, approximately 22,500 participants have been vaccinated across the country and the vaccine has been found to be safe,” Somani said.


Dosage, protection duration and storage: The vaccine will be administered in two doses and stored at 2-8° degrees Celsius. While the DCGI has not clarified the intervals between the shots, Bharat Biotech had earlier said the efficacy is to be determined only after 14 days post the second dose.

Union Health Minister Harsh Vardhan visits Guru Teg Bahadur Hospital to review the dry run drill for administering COVID-19 vaccine in New Delhi. (PTI)

Pricing: While there has been no talk on the price of Covaxin, reports have said Bharat Biotech will price the vaccine at Rs 350. The firm has already signed a letter of intent (LoI) with Ocugen to co-develop Covaxin for the US market.


Zydus Cadila ZyCov-D vaccine

Zydus Cadila has received the drug regulator’s nod to initiate Phase III clinical trials in around 30,000 volunteers.

Type of vaccine: Zydus Cadila’s ZyCov-D is a “plasmid DNA” vaccine. DNA vaccines use genetically engineered plasmids–a type of DNA molecule–that are coded with the antigen against which the immune response is to be built. The DNA sequence injected would match that of the virus, helping the body build antibodies against it.


Effectiveness: Last month, the company said the vaccine was found to be safe, well-tolerated and immunogenic in the Phase I/II clinical trials, which was conducted on around 1,000 volunteers.

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First published on: 03-01-2021 at 03:55:41 pm
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