There may be a glimmer of hope amid all the dark developments as the coronavirus steadily spreads around the planet.
First, the bad news. At least one expert, Harvard epidemiology professor Marc Lipsitch, believes that as many as 70 percent of people will ultimately catch the virus. Now, the good news. It appears that you can’t catch the disease twice. Maybe. That really matters. Not just for your own individual health, but for the world’s chances of eventually controlling the pandemic.
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What follows is based on preliminary findings from research that’s still in its beginning phases. There’s still a lot we don’t know about the flu-like disease that appears to have originated in an illicit wildlife market in Wuhan, China, in late 2019.
But we’re getting closer to saying with greater confidence that re-infection is impossible. That would mean the human race could build up so-called “herd immunity” that, in the future, should help to curtail coronavirus outbreaks.
And we have a bunch of monkeys to thank for that discovery.
Monkey fever
As the coronavirus raged across China in late 2019 and early 2020, Chinese scientists got to work. They quickly sequenced the virus’s genome and shared the data with researchers all over the world.
Another key finding came in late February, when a team from the Chinese Academy of Sciences discovered that the rhesus macaque, a species of 15-pound monkey that is common across Asia, can catch the coronavirus and display the same flu-like symptoms that human beings do.
“Animal models are essential for the study of pathogenesis of the viral infection, the evaluation of potential antiviral treatments or vaccine development,” the Chinese researchers explained.
And testing on the macaques soon led to another important discovery.
First, the scientists exposed macaques to the virus. A week later, right on schedule, the monkeys had flu-like symptoms. The scientists then pampered the monkeys until the animals’ own immune systems developed antibodies to beat back the virus.
The little primates were, in a word, “cured.”
That’s when the scientists exposed the macaques to the same coronavirus strain a second time. They waited a bit, then swabbed the monkeys’ noses and anuses, looking for evidence of the virus. “The monkeys with re-exposure showed no recurrence of COVID-19,” the scientists wrote, using the official name of the disease caused by the virus.
On March 13, a different Chinese Academy of Sciences team announced that macaques apparently can’t get COVID-19 twice.
Herd immunity
Public health officials all over the world surely sighed in relief. There had been some reports of human patients being infected with the coronavirus twice. If that were the case, it wouldn’t be hard to imagine coronavirus coming back in a big way, year after year, wreaking the same havoc it’s currently inflicting.
Those reports of re-infection may be mistaken. “I hypothesize that people tested negative but still had residual virus in their bodies that was below the limit of assay detection,” David O’Connor, a vaccine researcher at the University of Wisconsin-Madison, told The Daily Beast.
“Assay detection” basically means counting viruses in a host, all in a laboratory setting. There are lots of ways to do it involving different tests and scanners.
“Viruses have the ability to establish reservoirs that may not always be apparent,” O’Connor explained. They can pool in the eye or some other nook or cranny of the human body, avoiding detection until they spread again.
In other words, the patients who appeared to catch coronavirus twice possibly just had it all along, but briefly appeared to get better as the virus retreated to its hiding place.
Re-infection is a nightmare scenario. On the flip side, the results from China’s monkey labs—that re-infection apparently isn’t possible—could be great news for all of us. It might mean that, after most of us catch coronavirus and hopefully survive, we should be immune to a second infection.
If enough of us end up with coronavirus antibodies, then cities, states, countries, and even the whole human species could develop “herd immunity” that makes future outbreaks smaller and smaller as time goes on.
Of course, hoping for herd immunity doesn’t mean you don’t also take other steps to control the virus the first time it strikes.
Banking on herd immunity to develop quickly, the United Kingdom initially took a rather relaxed approach to the coronavirus. Then a study by the Imperial College London showed that depending on herd immunity alone could still lead to 510,000 people dying in the U.K. and 2.2 million dying in the U.S.
London quickly changed its approach and began urging people to self-isolate.
But wait
All this science regarding re-infection is preliminary. It might also be wrong. “Our outbreak is too new to know,” Anna Wald, an infectious disease expert at the University of Washington, told The Daily Beast. “There is some emerging data from China that re-infections are possible.”
O’Connor and other researchers all over the world are working hard to refine the animal models for coronavirus. They need time to confirm that the macaque’s apparent immunity is for real, that it will last, and that people are likely to respond the same way.
“We do not know how long people are immune from reinfection, only that in a small monkey study a few animals did not get reinfected when rechallenged,” O’Connor said. “More will be known in the coming months.”
And even if macaques and people are immune to reinfection, there are plenty of other questions O’Connor and other scientists need to answer.
“Do vaccines elicit protective immunity, or are there circumstances where pre-existing immunity can enhance disease?” O’Connor asked. “How long does immunity last? Does the amount of virus that starts an infection determine how severe the infection will become?”
“The one thing that is needed, but is a huge ask, is patience,” he said. “It takes time to design and execute studies effectively. We all want answers yesterday and the few scientists working in this area of research have not had much sleep lately.”
