Dr. Shuvomoy Banerjee, PhD; Neucrad Health Desk, July 22, 2020
Covid-19 killing more than six lakh people worldwide has made the situation of novel coronavirus infection quite distressing. A few days ago, Current Chief Scientist of World Health Organization (WHO), Dr. Soumya Swaminathan conducted an important discussion with the other country representative members of the Organization about how Covid-19 vaccines could reach to people as soon as possible. Reviewing the latest developments in vaccine research, she has informed that Oxford University is at the forefront of covid-19 vaccine research. AZD1222, a vaccine developed by Oxford University and its partner, the British-Swedish pharmaceutical company named AstraZeneca has been used in human trials (Phase-I / II). Oxford scientists very recently confirmed that the mentioned trial has yielded remarkable results. Moreover, their research work has been published in the famous research journal “Lancet“. The journal’s editor, Richard Horton, tweeted that the successful vaccine is on the way!
Of note, research on the AZD1222 vaccine began at the Jenner Institute, run by the Nuffield Department of Medicine at Oxford University. At an early stage their project “COV001” was got approved for human clinical trial. Dr Sarah Gilbert, a professor and head of vaccine research at Nuffield Department of Medicine informed of using “ChAdOx1 Adenoviral Technology” to develop this vaccine.
The technology involves the concept that adenovirus which is capable of causing mild infections in the upper part of the lungs can be used as a ‘vector’ which can easily enters inside the cells. The vector thus obtained is called “Adenoviral vector”. By scientifically excluding the genes responsible for infection, only the desired genes making up the spike protein of SARS-CoV-2 have been cloned. According to Prof. Gilbert, this strain of adenovirus is derived from a species of chimpanzee. It does not infect as well as circulate in human population and therefore, people won’t develop any previous immunity against this strain. As a result, this vector is very safe and suitable for making vaccines.
Previous Use of ChAdOx1 adenoviral technology:
ChAdOx1 adenoviral technology has been already used as a candidate vaccine for flu, chikungunya, Zika virus, and Middle East Respiratory Syndrome (MERS) infections before. Interestingly, clinical trials of this vaccine’s Phase-III are currently underway in the UK, South Africa and Brazil. Moreover, the trial will begin in the United States in a few days.
Results and Working mechanism of AZD1222 vaccine:
The AZD1222 vaccine was tested on 1,077 healthy people (Age range: 18-55yrs) in a clinical trial led by Oxford University. Scientists at Oxford University observed that their vaccine yielded two important results after the trial:
- According to the trial results as published in Lancet, about four times increase of antibodies against SARS-CoV-2 are produced in 95 percent of people within a month of their first vaccine dose.
- The highest T-lymphocyte response occurred 14 days after the vaccination lasting for two to three months.
The vaccine is being said to work in two possible ways against Covid-19:
- AZD1222 vaccine helps in the production of neutralizing antibodies in the human body.
- The vaccine plays a key role in the production of killer cytotoxic T-lymphocytes. Studies suggest that such killer T-lymphocyte may stay in the body for a long time and destroy the virus by identifying the infected cells.
Professor Andrew Pollard, chief investigator at the Oxford Vaccine Trial, informed that AZD1222 vaccine had no specific side effects. The vaccine sufficiently produces specific antibodies against the novel corona virus, but further clinical trials are needed to determine the detailed effectiveness of the vaccine. AstraZeneca has informed they will distribute two billion doses of the vaccine to Britain, Europe, America, India and other countries, once the final clinical trials become successful. They have already discussed the matter with the Serum Institute of India. Henceforth, at his moment everyone starting from the general public to the eminent scientists is looking eagerly to the final stage of this vaccine trial. It is to be mentioned the
- Folegatti PM, Bittaye M, Flaxman A, et al. Safety and immunogenicity of a candidate Middle East respiratory syndrome coronavirus viral-vectored vaccine: a dose-escalation, open-label, non-randomised, uncontrolled, phase 1 trial [published correction appears in Lancet Infect Dis. 2020 May 12;:] [published correction appears in Lancet Infect Dis. 2020 Jun 8;:]. Lancet Infect Dis. 2020;20(7):816-826. doi:10.1016/S1473-3099(20)30160-2
- Lane R. Sarah Gilbert: carving a path towards a COVID-19 vaccine. Lancet. 2020;395(10232):1247. doi:10.1016/S0140-6736(20)30796-0
- Mullard A. COVID-19 vaccine development pipeline gears up. Lancet. 2020;395(10239):1751-1752. doi:10.1016/S0140-6736(20)31252-6