Like the WHO, the Central Drugs Standard Control Organisation, United States Food and Drug Administration, European Medicines Agency and others also recommend certain norms prior to rolling out of vaccines for mass immunization.

To increase the availability of safe and effective vaccines in India, the Central Drugs Standard Control Organisation (CSDSO) issued a set of guidelines on April 15 stating that foreign produced vaccines which have been granted emergency approval for restricted use by US Food and Drug Administration, European Medicines Agency, UK Medicines and Healthcare products Regulatory Agency, Pharmaceuticals and Medical Devices Agency Japan or which are listed in The WHO Emergency Use Listing may be granted Emergency Approval in India.

Vaccines developed by BioNTech/Pfizer and Moderna became the first vaccines to be granted emergency use authorization by the US Food and Drug Administration and European Medicines Agency for use in USA and Europe.

Before this, emergency use approvals have been granted to vaccines against Anthax, Ebola, Enterovirus, H7N9 Influenza and Middle East Respiratory Syndrome.

What is EUL?

WHO developed the Emergency Use Assessment and Listing (EUAL) mechanism in response to the 2014-2016 Ebola virus disease outbreak. The EUAL is a risk-based procedure for assessing and listing unlicensed vaccines, therapeutics and in vitro diagnostics for use during public health emergencies of international concern.

EUL opens the door for countries to expedite their own regulatory approval process to import and administer the vaccine. According to the WHO, there are four criterions that must be met to obtain this approval:

• The disease for which the product is intended is serious or immediately life threatening, has the potential of causing an outbreak, epidemic or pandemic and it is reasonable to consider the product for an EUL assessment, e.g., there are no licensed products for the indication or for a critical subpopulation (e.g., children)
• Existing products have not been successful in eradicating the disease or preventing outbreaks (in the case of vaccines and medicines)
• The product is manufactured in compliance with current Good Manufacturing Practices (GMP) in the case of medicines and vaccines and under a functional Quality Management System (QMS) in the case of IVDs
• The applicant undertakes to complete the development of the product (validation and verification of the product in the case of IVDs) and apply for WHO prequalification once the product is licensed.

Which ones got the approval?

Here's a list of vaccines granted the Emergency Use Listing by the WHO with a timeline:

June 1, 2021: CoronaVac developed by China-based, Sinovac Biotech

May 7, 2021: Sinopharm produced by Beijing Bio-Institute of Biological Products Co Ltd, subsidiary China National Biotech Group

April 30, 2021: Moderna or mRNA 1273 vaccine developed by Massachusetts-based Moderna Inc

March 12, 2021: Janssen developed by Johnson & Johnson

February 15, 2021: Astrazeneca/Oxford vaccine, registered in India as Covishield, produced by Astrazeneca-SKBio (Republic of Korea) and Serum Institute India

December 31, 2020: Comirnaty COVID-19 mRNA vaccine developed by Germany-based BioNTech and USA-based Pfizer

Vaccines awaiting approval

Covaxin: WHO has recently accepted expression of interest for EUL of Bharat Biotech's Covaxin. The process of getting the status of EUL started in April and a pre-submission meeting was held on June 23 where Bharat Biotech presented a summary of the overall quality of shot. The Phase III clinical trial results are yet to be made public. Interim data of Phase III suggests that Covaxin has shown 77.8% efficacy.

Around 90% of the documents have been submitted to the WHO and the remaining are to be in by June, Bharat Biotech International Limited (BBIL) said in May.

Covaxin, developed jointly by Bharat Biotech International Limited and Indian Council of Medical Research is an inactivated whole virion COVID-19 vaccine. It was evaluated through Phase I and Phase II trial for safety and reactogenicity. It was granted emergency use approval in India on January 3, 2021.

Convidecia: China-based vaccine maker CanSino Biologics Inc manufactured Convidecia (Ad5-nCoV), a one-shot adenovirus vector vaccine. Convidecia received approval for emergency use by Hungarian National Institute of Pharmacy and Nutrition on March 22. The authorisation was based on the interim results of Phase III clinical trial. On February 25, it was granted conditional marketing authorisation by the National Medical Products Administration of China (NMPA).

Convidecia was also approved for emergency use in Chile on April 8 by the Intituto de Salud Publica de Chile, by Federal Commission for Protection Against Sanitary Risks of Mexico and by the Drug Regulatory Authority of Pakistan for administration on adults above 18 years of age in February 2021.

Apart from this, Chinese NMPA approved the emergency use of another vaccine in March 2021. This is the Recombinant Novel Coronavirus Vaccine (CHO Cell) produced by Chinese Academy of Sciences and Anhui Zhifei Longcom Biopharmaceutical Co. Ltd.

While the dossier for Convidecia has been accepted for review by WHO for the Emergency Use Listing, additional information is requested for the other Recombinant Novel Coronovirus Vaccine.

Sputnik V: This vaccine received emergency use authoritisation in India on April 12 and it could be imported from Russia amidst India's vaccine crunch. But, ANVISA-Brazil National Health Surveillance Agency decided not to authorise Sputnik V in Brazil over concerns with development and production of vaccine as well as lack of consistent and reliable data.

The single dose variant, Sputnik Light, a heterologic, recombinant adeno-virus based vaccine, has been approved for use only in Angola, Bahrain and Russia while still being evaluated in clinical trials. Both of these have still not been authorized by WHO for emergency use.

According to an AFP report, Sputnik V is already being used in 40 countries.

Apart from these, according to a recent WHO record, expression of interest for granting Emergency Use Listing has been accepted for CureVac's Zorecimeran concentrate and solvent for dispersion for injection and Sanofi Pasteur's CoV2 preS dtM-AS03.

Chinese IMBCAMS's SARS-CoV-2 Vaccine's expression of interest has not been accepted yet. Shots developed by Clover Biopharmaceuticals and Cuban manufacturer BioCubaFarma are still in discussion with the WHO on submission of the expression of interest and other related documents for the authorisation. But the other Cuban vaccine, Sobrena 2 along with BioCubaFarma's three-shot Abdala vaccine are close to receiving emergency use approval by local authorities.

Vaccines Undergoing Clinical Trials

Covovax: This vaccine candidate is now being manufactured by Serum Institute India, which received the license under agreement signed in August 2020 with the US-based pharmaceutical firm, Novavax Inc. to produce the nanoparticle protein-based vaccine-NVX-CoV2373.

On March 27, Adar Poonawalla tweeted about the beginning of Covovax trial in India and said that it has an overall efficacy of 89%.

Novavax is reported to get approval of US Food and Drug Administration by October for emergency use. Since Novavax has partnered with Serum Institute India for the WHO-backed COVAX programme, delivery to developing countries like India would be prioritized, CEO Stanley C Erck was quoted as saying after announcing the vaccine's performance in Phase III trials in the United States and Mexico.

Phase III trial of Covovax began on June 18 and Serum Institute India said they will apply for permission of Drug Controller and General of India (DCGI) to conduct a clinical trial of the vaccine on paediatric population. It is the second vaccine that is being produced by the Pune-based SII after Covishield.

Biological E: The Union Ministry of Health & Family Welfare has signed a deal with Hyderabad-based Biological E. Limited for 30 Crore Covid-19 vaccine doses. The vaccine is an RBD-protein sub-unit and will be manufactured and stock piled by Biological-E from August to December 2021. On April 24, Biological E informed that it has completed the Phase I and II trials of its Covid-19 vaccine and received the approval of Central Drugs Standard Control Organisation's nod to start the Phase III trial.

Biological E also has separate deal to produce 60 crore doses of Johnson & Johnson's Covid-19 shot annually. They announced on June 1 that Biological E has entered into a licensing agreement with Providence Therapeutics Holdings to manufacture the Canadian company's mRNA Covid-19 vaccine in India.

ZyCov-D: Indian pharmaceutical company Zydus Cadila is set to apply for emergency use authorization by the DCGI for ZyCoV-D, a DNA-based vaccine which carries the genetic code of that part of the virus that triggers the immune system of the body. If approved by the DCGI, this will be the first DNA-based vaccine with three doses to be made available to the people. According to Zydus Cadila, the three doses of Zycov-D, which uses plasmid-DNA, are to be administered on day 0, day 28 and day 56.

According to Regulatory Affairs Professionals Society, a US-based non-profit involved with the regulation of health care and related products, EpiVacCorona and CoviVac developed by Russia, Convidicea, WIBP-CorV, ZF2001 developed by China and Uzbekistan and CoVIran Barekat developed by the Iranian Shifa Pharmed Industrial Group, QazVac by Kazakhstan and a couple of others, yet unnamed are under various stages of clinical trial and approval by different health agencies. Also, there are nearly 86 different vaccines, some still unnamed, still in different development stages.