COVAXIN^TM (BBV152) is India’s first indigenous, whole-virion, inactivated vaccine developed by Bharat Biotech in collaboration with the Indian Medical Research Council (ICMR) and the National Institute of Virology (NIV) for the treatment of highly infectious disease Covid-19.

The vaccine is derived from the Vero cell platform and is manufactured at Bharat Biotech’s BSL-3 (Bio-Safety Level-3) high containment facility located in Genome Valley, Hyderabad, India.

Bharat Biotech’s Covid-19 vaccine (COVAXIN) has been approved for restricted use in an emergency to prevent Covid-19 with two-dose regimen at four weeks apart.

The COVAXIN is injected directly into the deltoid muscle that is accessible in the upper arm.

COVAXIN approvals

In January 2021, the Drug Controller General of India (DCGI)-Central Standards Control Organization (CDSCO), Ministry of Health & Family Welfare, granted emergency use authorisation approval for emergency usage of COVAXIN in India.

The Central Licensing Authority also approved the sale or distribution of COVAXIN for restricted use in emergencies of public concern as an excess of precautions in clinical trial mode. The restricted priority groups will receive the vaccine under the plan.

COVAXIN impact will not be examined against any other intervention through this effort and the patient will be monitored for any adverse reaction and supported by medical care under the existing public health programme. The vaccine has a safe track record with more than 300 million doses delivered.

Bharat Biotech filed an application to conduct clinical trials in Bangladesh. Several countries around the world have approached Bharat Biotech for the procurement of COVAXIN. India plans to export COVAXIN supplies to Mongolia, Myanmar, Sri Lanka, the Philippines, Bahrain, Oman, Maldives and Mauritius.

In December 2020, Ocugen and Bharat Biotech signed a binding letter of intent (LoI) to collaborate on clinical development, registration and commercialisation COVAXIN for the US market. As per the LoI, US rights to the vaccine candidate will be held with Ocugen.

In January 2020, Bharat Biotech was contracted by Precisa Medicamentos for the supplies of COVAXIN to Brazil. The vaccine supplies will be procured by the Brazilian government through the direct procurement process and will be prioritised to the public market.

Covid-19 causes and symptoms

Coronavirus disease 2019 (Covid-19) is caused by a new coronavirus, now known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Coronaviruses are enveloped positive-sense RNA viruses containing very large genomes of all RNA viruses, usually 27kb to 32kb.

The virus has a distinctive fringe of large, distinctive, petal-shaped, crown-like spike.

The virus transmission occurs mainly person-to-person via close contact. It can impact the upper respiratory tract (sinuses, nose, and throat) or lower respiratory tract (windpipe and lungs). The severity of infection may vary from very mild to severe.

People with Covid-19 may experience a wide variety of mild to severe symptoms from two to 14 days after exposure to the virus. The duration between exposure to the virus and symptom onset is considered as the incubation phase.

Common symptoms of the condition include cough, fever or chills, shortness of breath, tiredness, nasal congestion, headache, conjunctivitis, muscle or body pain, sore throat, loss of taste or smell, diarrhoea and nausea or vomiting in people of all age groups.

COVAXIN mechanism of action

COVAXIN is an inactivated vaccine obtained from the SARS-CoV-2 strain isolated at the NIV, Pune, an Indian virology research institute.

The vaccine is used along with immune stimulants, commonly known as vaccine adjuvants (Alhydroxiquim-II), to improve immune response and longer-lasting immunity. The vaccine candidate is produced through the formulation of the inactivated virus with Kansas-based ViroVax’s Alhydroxiquim-II adjuvant.

COVAXIN mainly contains 6µg of whole-virion inactivated SARS-CoV-2 antigen (Strain: NIV-2020-770), and the other inactive components such as 250µg aluminium hydroxide gel, 15µg TLR 7 / 8 agonist (imidazoquinolinone), 2.5mg TM 2-phenoxyethanol, and phosphate buffer saline up to 0.5ml.

The vaccine requires no sub-zero storage and reconstitution requirement and available for use in multi-dose vials, stable at 2-8℃.

Clinical trials on COVAXIN

In June 2020, the DCGI-CDSCO, Ministry of Health & Family Welfare, issued permission to begin phase one and two human clinical trials following the demonstration of safety and immune response in the preclinical studies.

Preclinical research has shown high immunogenicity and protective efficacy in animal challenge studies undertaken in hamsters and non-human primates.

A total of 375 patients were recruited in phase one trial and established excellent safety data without any reactogenicity. Vaccine-induced neutralising antibody titers of two divergent SARS-CoV-2 strains were observed. The percentage of all side-effects combined among vaccine patients was just 15%.

In the phase two study, 380 patients aged 12-65 years were enrolled. COVAXIN has contributed to tolerable safety results and improved humoral and cell-mediated immune responses.

The phase three trial, which began in mid-November 2020, is India’s first and the largest third phase efficacy trial to be ever conducted for Covid-19.

The multi-centre, double-blinded study enrolled 27,000 participants across India. The participants receive two intramuscular injections within 28 days.

Initial first vaccination dose was given to all participants and the second dose of either vaccine or placebo is currently being administered.

Efficacy is determined by the occurrence of Covid-19 cases between the vaccine and the placebo arm, which will start two weeks after the second dose. The preliminary efficacy estimation will be obtained by the end of February 2021.

The side effects observed with COVAXIN include pain, swelling, redness, and itching at the injection site, as well as body ache, weakness, stiffness, nausea, vomiting, fever, malaise and headache.