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Covid-19: What do we know so far about a vaccine?

BMJ 2020; 369 doi: (Published 27 April 2020) Cite this as: BMJ 2020;369:m1679

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  1. Elisabeth Mahase
  1. The BMJ

The World Health Organization has announced that 83 potential covid-19 candidate vaccines are being assessed (as at 23 April), including seven that have now been approved for human testing through clinical trials.1The BMJ looks at what we know so far.

What do we know about the seven approved candidates?

Of the seven, three are being tested in Beijing. The vaccine company CanSino Biological, in collaboration with the Beijing Institute of Biotechnology, has the only vaccine in a phase II trial.2 The vaccine, which uses an adenovirus vector, is set to be tested in 375 healthy adults, with 125 people in the control group, and will look at adverse reactions within 14 days and at levels of covid-19 neutralising antibodies and of antibodies against the coronavirus spike protein at day 28. Participants will be followed for up to six months. However, while the move to phase II is a good sign, the results of the phase I trial, which looked at adverse reactions seven days after injection, have not been made public.

Sinovac, another Beijing based company, is currently testing its inactivated-virus covid-19 vaccine (PiCoVacc) in a randomised, double blinded, placebo controlled phase I trial involving 144 adults.3 The company is planning to test the vaccine on another 600 people during the phase II trial. A preprint concerning the vaccine’s effectiveness in mice, rats, and non-human primates found that it conferred “ complete protection” against SARS-CoV-2 strains circulating worldwide.4 A third candidate, from the Beijing Institute of Biological Products and the Wuhan Institute of Biological Products, is also being evaluated, but little information …

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