The race for A vaccine against Covid-19 is in full swing. It has to be – without one, the before time never comes back. More than a hundred candidates are cooking, most of them for the time being. A handful are in early human trials, three in phase II clinical trials to determine if they actually confer immunity to the disease.
But nobody believes that finding a winner will be easy. The development of vaccines usually takes years. This is the time when researchers and governments don’t feel that way. Worldwide, more than 4 million people have fallen ill and 280,000 have died. In the United States alone, people seeking protection and closing businesses have cost 30 million jobs. As the famous virologist Peter Piot wrote in a report on his own experience after the illness with Covid-19, “the only real exit strategy from this crisis is a vaccine that can be launched worldwide.”
Even if scientists develop a safe, generally effective vaccine, no one knows how to give it to billions of people. It will be scarce at first and, depending on how it works and how it is made, may be difficult to transport. You need to figure out how to use it now so that people on a planet who need help can get it.
One approach could be to initially only administer the vaccine to members of certain groups. Of course, someone has to decide which groups have priority. This order will be difficult to figure out. Even if the answer is “who is most at risk of dying?”, The epidemiological data are still not clear which group meets this criterion. Older people are more likely to get seriously ill and die, but researchers are still trying to figure out the role children play, for example, as carriers. “The finer that is, the better we can define the risk groups, both in terms of the risk of infection and the risk of serious consequences,” says Andreas Handel, modeler for infectious diseases at the University of Georgia.
And “most at risk” is not necessarily the right answer. Maybe high risk people from to catch The disease, but with a lower risk of poor results, should come first. This could mean prioritizing people with high exposure jobs that involve a lot of public contact, or addressing the systemic issues that have caused poorer, African American and Latin American people to be more exposed to diseases and deaths from Covid-19. That is not easy. “It can be groups with underlying health conditions or people who cannot avoid contact because of their work – like healthcare workers, police officers, grocery workers,” says Handel.
Alternatively, the vaccine should possibly go to the groups for which it is immunologically best suited. The seasonal influenza vaccine, for example, is not as effective in the elderly. If a Covid-19 vaccine has the same limitation, it’s a big problem.
It could also be a solution. Perhaps the best choice is to give the vaccine to people who have the greatest immune response to it – perhaps young, healthy people – to start building some kind of herd immunity at the roundabout. “It could be conceptually possible that there are better age groups that do not need it so much, but indirectly protect the other age groups,” says Handel. “Then the question is, should you focus on giving the vaccine to those who don’t directly benefit the most because their risk is lower, but if they’re vaccinated, they can’t get it and give it to their parents? ”