Scientists took a major step last week in their attempt to develop a vaccine that could protect humanity from the effects of Covid-19. In Seattle, Washington, a few dozen volunteers received a vaccine as part of a phase-one safety trial that is sponsored by the US government. Similar trials are also set to begin elsewhere in the near future. These are promising developments.
But just how quickly will these projects deliver a product that, injected into men, women and children, could prevent them from succumbing to Covid-19 in future years?
Hanneke Schuitemaker, head of viral vaccine discovery and translational medicine at Janssen Pharmaceuticals, is working to develop just such a vaccine, and answers Observer science editor Robin McKie’s questions.
Do we know if people develop immunity against the Covid-19 coronavirus?
We know that people who have been infected with the virus develop antibodies to Covid-19 and we believe that these could protect them against future attacks from the Sars-CoV-2 virus, which is responsible for Covid-19. However, the virus is such a newcomer to science that it has not been possible to find out. Nor do we know how long such protection – from natural immunity – might last.
Do we know if the virus mutates rapidly like flu, or is more stable?
The first phylogenetic tree [a diagram showing the evolution of an organism] of the virus shows that there is some genetic drift in it – but whether that will be enough to have an effect on vaccine development is unclear. Everything is so new in dealing with this coronavirus.
How long will it take to get a vaccine ready for use now that we have begun preliminary trials?
At present, we have taken a single viral genome and have used it to create a vaccine of which tests are now starting. In the end, that single piece of virus will be the basis of a vaccine that will have to be given to billions of people. That will require extraordinary efforts in mass vaccine production – and that is bound to take time.
We need to ramp up manufacturing processes in readiness for the vaccine so that we have a head start when one is ready, and has demonstrated protective effectiveness in people – probably in about 12 to 18 months. On top of that, it may be that we will have to be ready to prepare vaccines for seasonal outbreaks of Covid-19 in coming years.
What sort of vaccine are we likely to end up with?
One approach is to get the immune system to make antibodies that recognise and block the spike protein that the coronavirus uses to enter human cells. However, other approaches might involve the body’s T killer-cells, which can recognise and kill infected cells.
What about trials? How long will they take?
There are several issues involved in the setting up of trials. Most importantly we neeed to identify a vaccine candidate that gives a good immune response in animal models.
Then there is the issue of the vaccine’s safety. For it to work we will have to give it to healthy people in the knowledge that they may never actually encounter the virus. In other words, they may never benefit from the vaccine’s protection yet they could be put at risk from potential side effects. So you will have to be very sure that your vaccine is safe in such circumstances. That means carrying out very large-scale trials and comparing results with placebo vaccines to make sure you have both a safe and an effective vaccine. And that takes time.