So there is no way to throw a net around Covid-19 and tighten it to nothing; his animal hosts will always provide him with an escape hatch. However, there is no real point in starting to think of alternative hosts until all potential human victims of a disease have been protected by vaccination – and so far we are not very close. . As long as people somewhere in the world are still waiting for their first snapshots, Covid-19 will have human hosts to reproduce. And also, potentially, to mutate, creating the kind of variants that are now appearing across the world.
This raises the possibility that as the virus changes, we will have to continue tinkering with vaccines to keep up with it. “I think most people think this will be something where we will probably have an injection of Covid-19 over the next few years,” Alex Gorsky, CEO of Johnson & Johnson, mentionned earlier this month at a CNBC event. “What exactly this plan will be made of, I don’t think we know today.”
If Covid can’t be a disease, we try to quell it quickly – like, say, we deploy vaccines to counter Ebola outbreaks – it has to become a disease we predict, like measles and flu. With measles, we start to vaccinate in childhood. With the flu, we revaccinate each year, while adjusting the content of the vaccine to follow the viral evolution. We vaccinate against them because they have such a record. Over the past 10 years, influenza killed between 12,000 and 61,000 people per year in the United States; globally, measles kills 140,000 each year.
We have no guarantee that Covid-19, if it becomes rampant, will be as fierce as measles, or mellow into anything mild. Before the start of the pandemic, there were six coronaviruses known to infect humans: the original SARS of 2003; Le MERS, born in 2012; and four that cause seasonal illness. The latter four, which are now considered endemic, are responsible for about 25% of the colds we get each winter, and they demonstrate that some coronaviruses can turn into something we don’t like, but don’t have. to fear. (They haven’t always been gentle, however. One of them was recently bound to a worldwide epidemic in 1889 and 1890 of respiratory diseases and neurological problems; it went down in history as the “Russian flu” – but that name was an estimate of its cause, since influenza viruses were not identified until 40 years later.)
A recent article modeling the potential future of the novel coronavirus, written by postdoctoral fellow Jennie Lavine of Emory University, attempts to predict how Covid-19 might behave in the future, based on data collected from the four endemic coronaviruses, as well than SARS and MERS. He finds that Covid-19 could reach the state that the four endemic strains now occupy, regularly causing mild illness for the most part, but this outcome will depend on the behavior of the circulating illness in children during their first infections, as these are the first. infections that cause the immune system to respond later.
This is the same function that vaccines perform, of course. Our bodies create several types of immunity in response to pathogens; It’s too early, Lavine says, to put together the long-term data we’ll need in order to know whether the Covid-19 vaccination and childhood infection both protect each other so that any subsequent infection only produces one. mild illness.
But let’s assume, for now, that the virus does not turn into a mild infection like a common cold, but remains an unpredictable dangerous infection. This prospect makes it more urgent to defuse vaccine nationalism and distribute doses worldwide as quickly as possible, not only to protect people from disease, but also to deprive the virus of hosts in which it can mutate.