Trials and errors: the slow, painstaking path to a virus vaccine

There is a long list of medical and logistical hurdles to be cleared before any Covid-19 vaccine can be declared safe for use on the general public

There is a long list of medical and logistical hurdles to be cleared before any Covid-19 vaccine can be declared safe for use on the general public

What does it take to declare that a vaccine is not just effective but safe? Vaccines are some of the safest medical products in the world, but that is primarily because of the fastidiousness of their trials to ensure their efficacy.

After pre-clinical testing on cells and animals such as mice and monkeys, vaccines move into phase 1 trials, where a range of doses are given to a small number of people to test for ...