So there is no way to cast a net around Covid-19 and tie it to nothing; his animal hosts will always give him an escape hatch. However, it is not really helpful to think about alternative hosts until all potential human victims of a disease have been protected by vaccination – and so far, we are not that far away. As long as humans around the world are still waiting for their first images, Covid-19 will have human hosts to reproduce in. And possibly also to mutate in, creating the kind of variants that are now appearing all over the world.
That raises the possibility that if the virus changes, we’ll have to keep tinkering with vaccines to keep up. “I think most people think this will be something where we will likely get a Covid-19 shot in the coming years,” Alex Gorsky, Johnson & Johnson’s CEO, said at a CNBC event earlier this month. “Exactly what that shot will consist of, I don’t think we know today.”
If Covid cannot be a disease that we are quickly trying to suppress – such as, for example, we are rolling out vaccines to combat Ebola outbreaks – it must become a disease that we plan on, such as measles and the flu. With measles, we start vaccinating in childhood. In the case of flu, we vaccinate again every year, while adjusting the content of the vaccine to the viral evolution. We vaccinate against them because they take such a toll. In the past 10 years, influenza has killed 12,000 to 61,000 people every year across the US; Worldwide, 140,000 people die of measles every year.
We have no guarantee whether Covid-19, if it becomes endemic, will be as ferocious as measles, or soften to something mild. Before the pandemic began, there were six coronaviruses known to infect humans: the original 2003 SARS; MERS, founded in 2012; and four that cause seasonal illness. Those last four, now considered endemic, are responsible for about 25 percent of the colds we catch each winter, and they show that some coronaviruses can become something we don’t like, but don’t have to fear. to be. (They weren’t always mild, however. One of them has recently been associated with a worldwide epidemic in 1889 and 1890 of respiratory illness and neurological problems; it came down in history as the ‘Russian flu’ – but that name was a guess the cause, as flu viruses weren’t identified until 40 years later.)
A recent paper modeling the potential future of the novel coronavirus, written by Emory University postdoc Jennie Lavine, seeks to predict how Covid-19 might behave in the future, based on data collected from the four endemic coronaviruses, plus SARS and MERS. It is noted that Covid-19 could reach the state that the four endemic strains now occupy, regularly causing mostly mild diseases – but that outcome depends on how the circulating disease behaves in children during their first infections, as the first are infections that cause the immune system to respond along the way.
That is, of course, the same function that vaccines perform. Our body creates multiple types of immunity in response to pathogens; It’s too early, Lavine says, to gather the long-term data we need to know if the vaccination against Covid-19 and the infection in children both protect so much that any subsequent infections cause only mild illness.
But for now, assume the virus won’t turn into a mild infection like a cold, but will remain an unpredictably dangerous one. That 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 deprive the virus of the hosts in which it can mutate.