BORDERLINE UNETHICAL

Should we short-circuit trials of experimental COVID-19 vaccines?

- BANJOT KAUR

IS IT ethical to administer an experimental COVID-19 vaccine to a healthy person and then infect him/her with the novel coronavirus to check if the vaccine has immunised the individual against the pathogen? The question is at the centre of a global debate ever since the UK allowed a study, called human challenge trial (HCT), on a COVID-19 vaccine which will be conducted in January 2021.

Normally, a vaccine goes through three phases of human trials. The first phase tests for safety, the second immunogenicity (ability to trigger immune response) and the third involves large-scale testing on tens of thousands of participants of varied populations, who are injected with the vaccine and observed over a long period, even years, for efficacy. In HCT, instead of the third phase trial, a small number of healthy participants (often less than 100) are recruited, at times for money, and administered the vaccine before being injected with a less virulent strain of the virus. HCT thus reduces the trial period by months. The danger, however, is that the injected virus may cause severe illness or even death of the participants during the study.

HCT is not a new concept. It was used for the development of anti-malarial and cholera vaccines in the 1970s. But when HCT was undertaken to develop vaccines for these diseases, drugs to treat them were already there. If a participant became ill, there was a cure available. This is not the case with COVID-19, because there is no guaranteed cure.