Good results from three Covid-19 vaccine candidates: Report

Neutralising antibodies does not prove effective vaccine but important early step, says expert

As the world has seemingly come to a standstill due to the Covid-19 pandemic, medical researchers have been labouring hard to develop a vaccine against the coronavirus which has killed over 6 lakh people worldwide.

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At present, nearly 200 vaccine candidates are in different stages of trial all over the world, according to The Lancet.

In addition, more than 150 countries have expressed interest in joining the COVAX facility, a mechanism designed to guarantee equitable and fair access to Covid-19 vaccines, the World Health Organisation has said.

Among the vaccine candidates, three have reached the final stage of trial. The vaccine named AZD1222, developed by the University of Oxford and pharmaceutical company AstraZeneca, seems to be the most promising one yet, multiple news outlets reported. The other two are Moderna Inc’s vaccine and Sinovac Biotech vaccine.

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Published in the journal The Lancet, the Oxford vaccine has been found to be relatively safe. All of its 1,077 volunteers, who received the vaccine in the first and second phase of the trial, have developed neutralising antibodies against Covid-19. These antibodies are proteins that prevent the virus from infecting healthy cells. It also helped the immune system to protect and attack cells that are already infected by the virus.

Professor Adrian Hill, director of Oxford's Jenner Institute, said that the latest data is very "encouraging" and that the experts are "seeing both arms of the immune systems stimulated very strongly by the vaccine”, ABC News reported.

While large-scale third phase human trials of the Oxford vaccine have already started in Brazil, AstraZeneca has teamed up with Serum Institute of India (SII) to produce the potential vaccine in India, LiveMint said in an article.

The American pharmaceutical company, Moderna Inc, produced a vaccine which passed the initial safety trial. However, the researchers later realised that the antibodies produced by the vaccine showed some side effects during the human trial of the Moderna’s vaccine candidate.

A doctor and researcher at the Duke Human Vaccine Institute Tony Moody, said that the production of neutralising antibodies does not prove that the vaccine will be effective though it is an important early step in the trial.

Known as CoronaVac, Chinese pharmaceutical company Sinovac Biotech’s vaccine candidate has started the third phase of the trial. It has teamed up with Butantan Institute, a Brazilian public health research centre for the clinical trial. About 9,000 public health workers will receive the vaccine in two doses over the next three months. The initial results are expected within 90 days, said Sao Paulo Governor Joao Doria.