Corbevax or BioE COVID-19 or Becov2, is a COVID-19 vaccine candidate developed by Indian biopharmacutical firm Biological E. Limited (BioE), the Baylor College of Medicine in Houston, United States, and Dynavax Technologies. It is a protein subunit vaccine.

In April 2021, the Drugs Controller General of India permitted the vaccine candidate to start phase III clinical trials. On 3 June, India's Ministry of Health and Family Welfare pre-ordered 300 million doses of Corbevax. So , today I am trying to figure out what this vaccine is ?

WHO is the agency which is guiding nations on Covid response. The information provided is from WHO's website or other popular websites. Please visit WHO's Vaccination Explanation series -> https://www.who.int/emergencies/diseases/novel-coronavirus-2019/covid-19-vaccines/explainers.

WHO's article on Differnt Types of Vaccines - > https://www.who.int/news-room/feature-stories/detail/the-race-for-a-covid-19-vaccine-explained

(Image from WHO's website)

As you can see above, there are three main approaches in designing a vaccine. Their differences lie in whether they use a whole virus or bacterium; just the parts of the germ that triggers the immune system; or just the genetic material that provides the instructions for making specific proteins and not the whole virus.

According to WHO's information on public domain, there are total 102 vaccines under Human trial. 

Now coming to the Biological E vaccine under trials, it is a protein sub-unit vaccine. It uses following technologies - 

The vaccine candidate includes an antigen in-licensed from BCM Ventures, Baylor College of Medicine's integrated commercialization team, along with

Dynavax's advanced adjuvant CpG 1018.

The candidate consists of the receptor binding domain of the SARS-CoV-2 spike protein adjuvanted with CpG 1018 plus alum

What is Adjuvant?

An adjuvant is an ingredient used in some vaccines that helps create a stronger immune response in people receiving the vaccine. In other words, adjuvants help vaccines work better. Some vaccines that are made from weakened or killed germs contain naturally occurring adjuvants and help the body produce a strong protective immune response. However, most vaccines developed today include just small components of germs, such as their proteins, rather than the entire virus or bacteria. Adjuvants help the body to produce an immune response strong enough to protect the person from the disease he or she is being vaccinated against. Adjuvanted vaccines can cause more local reactions (such as redness, swelling, and pain at the injection site) and more systemic reactions (such as fever, chills and body aches) than non-adjuvanted vaccines. (Source : https://www.cdc.gov/vaccinesafety/concerns/adjuvants.html#cpg1). 

Aluminum salts, such as aluminum hydroxide, aluminum phosphate, and aluminum potassium sulfate have been used safely in vaccines for more than 70 years. The uniqueness of Biological E vaccine is, it uses latest Adjuvant - Cytosine phosphoguanine (CpG), a synthetic form of DNA that mimics bacterial and viral genetic material (CpG 1018). 

“We are proud to contribute CpG 1018 to support development of an adjuvanted vaccine to prevent COVID-19. CpG 1018’s potential to boost the immune response to produce more antibodies and longer lasting immunity may also minimize the dose of antigen needed, enabling vaccination of a greater number of people,” said Ryan Spencer, chief executive officer of Dynavax on Bayor College of Medicine Website (here). 

Basically it contains syntethic DNA type material with antigen to generate immuno response.