11 critical unanswered questions about the coronavirus and COVID-19, the illness it causes

11 critical unanswered questions about the coronavirus and COVID-19, the illness it causes

coronavirus covid 19 glass virsu structure shape receptors glass model GettyImages 1213231979

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A glass model of the novel coronavirus, which causes the disease COVID-19, by artist Luke Jerram on March 18, 2020 in Bristol, United Kingdom. The model is about 1 million times larger than the actual virus.

  • Experts are racing to study the coronavirus as the number of people it infects and kills continues to rise.
  • Scientists know the coronavirus likely came from bats but aren't sure how it hopped over to humans.
  • Researchers are also unsure what makes the virus so effective at spreading, and why it's lethal for some healthy people yet doesn't cause symptoms in most children.
  • It is also still unknown whether the virus is seasonal, can reinfect patients, or if a safe and effective vaccine will emerge to curtail the disease.
  • Visit Business Insider's homepage for more stories.
In the realm of medicine, what you don't know can, indeed, kill you.When it comes to the novel coronavirus, technically known as SARS-CoV-2, and the disease it causes, called COVID-19, the number of things experts are still trying to understand seems to outweigh what they can say for certain.
That is little surprise to any infectious-disease researcher: Highly contagious diseases can move through communities much more quickly than the methodical pace of science can produce vital answers.

What we do know is that the coronavirus apparently emerged in Wuhan, China, just before the New Year, has reached more than 175 countries, is confirmed to have infected more than 595,000 people, and has killed at least 27,000. Increased testing, particularly in the US, is bound to boost those numbers.

As hospitals around the world strain to care for patients with critical, long-lasting, and resource-draining pneumonia and respiratory failure, scientists are racing to study the coronavirus, spread life-saving information, and combat dangerous misunderstandings.

Here are 11 of the biggest questions surrounding the coronavirus and COVID-19, and why answering each one is critically important.

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Where exactly did the coronavirus come from?

Where exactly did the coronavirus come from?

The first coronavirus infections emerged in or around a wet market in Wuhan, in the Hubei Province.

Researchers are fairly certain that the virus — which is a spiky ball roughly the size of a smoke particle — developed in bats. Lab tests show it shares roughly 80% of its 30,000-letter genome with SARS (sever acute respiratory syndrome), a virus that also came from bats and triggered an epidemic of contagious respiratory disease in 2002 and 2003.

What's less clear is how or by what, exactly, the novel coronavirus made the jump from bats to humans. In the case of SARS, a weasel-like civet was the intermediate animal host. Researchers suspect civets, pigs, snakes, or possibly pangolins — scaly nocturnal mammals often poached for keratin in their scales — are a likely host for the new coronavirus.

A research group in China published early results that point to pangolins (which can die from coronaviruses) as the vector for humans, showing 99% genetic similarity. But the group's study and data were, as of February, not yet peer-reviewed or published. It may very well be that te virus jumped straight from bats to humans.

Why it matters: Understanding how novel zoonotic diseases evolve and spread could lead to improved tracing of and possibly treatments for new emerging diseases.

How many people actually have a COVID-19 infection?

How many people actually have a COVID-19 infection?

Global tallies of the number of cases, deaths, recoveries, and active infections just reflect the confirmed numbers — researchers suspect the actual spread of cases is far, far larger.

For every person who tests positive for the novel coronavirus, there may be five to 10 times more undetected cases, according to a study published March 16 in the journal Science. This is because testing capacity lags behind the pace of the disease, and many governments — including in the US — failed to implement widespread testing early on.

Why it matters: An accurate assessment is critical in helping researchers better understand the coronavirus' spread, mortality rate, the prevalence of asymptomatic carriers, and other factors. It would also show how effective social distancing, lockdowns, and quarantining are in preventing the spread of the disease.


What makes the coronavirus so good at spreading?

What makes the coronavirus so good at spreading?

Setting aside any debate about whether viruses are alive (or something else), they are small and streamlined particles that have evolved to make many, many copies of themselves by hijacking living cells of a host.

The measurement of a virus' ability to spread from one human is the R0, or R-naught; the higher the value, the greater the contagiousness — though it varies by region and setting. The novel coronavirus' R0 is roughly 2.2, meaning one infected person, on average, spreads it to 2.2 people. By comparison, the seasonal flu has an R0 of about 1.3.

Researchers don't yet understand why the coronavirus is so effective at spreading, though they have some ideas. One is that its surface proteins, which enable the virus to stick to host cells and invade them, attach with an especially strong latch, according to reporting by Ed Yong at The Atlantic.

The new coronavirus also seems to infect the upper and lower respiratory tracts, unlike SARS, which infected primarily tissue deeper in the lungs. And coughing — a signature symptom of COVID-19 — helps spread viruses in tiny droplets.

Why it matters: Knowing how a virus gets around can help everyone better prevent its spread. Getting a handle on its behavior may also spur governments to act sooner to contain future outbreaks of other similar diseases.

What actually drives mortality in people infected by the coronavirus?

What actually drives mortality in people infected by the coronavirus?

People who develop severe COVID-19 symptoms follow a fairly regular pattern.

On day one, patients often run a fever and experience muscle pain, fatigue, and a dry or unproductive cough. By day five, breathing is labored, and by day seven, they may be hospitalized. Day eight is when the situation can turn dire: Fluid starts filling up the lungs and blocking oxygen flow — a condition called acute respiratory distress syndrome. That fluid shows up as a telltale "ground glass" look on X-ray scans of the lungs (above).

The pattern of critical cases is alarming to clinicians, and something they're still trying to grasp: It's not just people with apparent risk factors like smoking and chronic illnesses who get severely ill — it's also seemingly healthy and young people.

The virus may replicate quickly enough to trigger the immune system very suddenly instead of gradually, causing it to go "berserk," according to one virologist interviewed by The Washington Post. In addition to damage caused by the virus, inflammation may further open up lung capillaries and cause them to leak more — causing fluid to quickly build up in the lungs, cut oxygen flow, and strain most organs in the body, including the heart (which must work harder).

Still, the disease has existed for less than three months and knowledge is evolving about what, exactly, makes it such a threat to a significant portion of patients.

Why it matters: Understanding how the coronavirus does so much harm could lead to more effective treatments in hospitals and make for promising drug targets.


What percent of people infected by the coronavirus die?

What percent of people infected by the coronavirus die?

Death rates for COVID-19 are not one-size-fits-all: Many factors are at work.

Age is a big one. Older generations are more likely to die as a result of lung failure caused by coronavirus infections, while younger generations are many times less likely. However, a person of any age can experience severe pneumonia, fatigue, and other worrisome symptoms.

Geographic location matters greatly, too. Governments that did not respond forcefully and early to the outbreak have seen emergency rooms and intensive care units crushed with patients who require round-the-clock care, outstripping resources and leading doctors to triage life-or-death decisions. The death rate in Italy, for example, is nearly eight times that of the US — though the progression of the latter country's outbreak is about two weeks behind that of the former.

Even weather conditions may influence the ability of the virus to spread, affecting the number of people it kills in a given population.

The reality is that the average death rate is variable, ever-changing, and won't get packaged into a reliable global average until the pandemic subsides.

Why it matters: Variations in death rates help researchers expose flaws in government responses, supply chains, patient care, and more, ideally leading to fixes. However, the early data is clear enough: The coronavirus cannot be ignored, since it has the capacity to kill millions in a relatively short amount of time.

Why are young people the least at risk of dying?

Why are young people the least at risk of dying?

On a per-capita basis, young people are the most resilient to the coronavirus. They do get infected and suffer from it, though: Nearly 30% of confirmed cases in the US are among people between ages 20-44, according to the CDC. That age category represents 20% of hospitalizations and 12% of ICU admissions.

"You are not invincible," Tedros Adhanom Ghebreyesus, the World Health Organization's director general, said during a press conference. "This virus could put you in the hospital for weeks or even kill you."

Very young children, however, rarely die from coronavirus (though kids are not invincible either.) Typically, kids and the elderly are in the same risk category from diseases like the flu. But it's not so with COVID-19: About 80% of deaths are in the 65-plus age group, while only a handful of young children have died from the illness.

Why that's the case is one of the coronavirus' greatest mysteries so far. Some early and notional explanations from medical professionals interviewed by The Washington Post suggest it may have something to do with the virus causing older, more mature immune systems to overreact and fill the lungs with excess fluid. But there may be an issue with surface receptors on the cells of young children.

Why it matters: Understanding why kids don't often show signs of the disease — either because they're not as prone to infection, or because they more often experience very mild, cold-like symptoms — could have huge ramifications for vaccine development and understanding how the disease spreads.


Can you get reinfected by the coronavirus?

Can you get reinfected by the coronavirus?

There have been a handful of cases where people who have tested positive for the coronavirus, later found to be free of the virus, and then later test positive again for it after developing symptoms again, according to The Guardian. One case in particular was with a tour guide in her 40s living in Japan.

These cases seem to be exceptions rather than the rule — and possibly the result of testing errors, experts say — the body almost certainly develops short-term immunity in the form of antibodies.

No one is certain about the prospects for long-term immunity, though, seeing as so little time has passed since the coronavirus emerged. But immune-system researchers are reasonably confident the body will recognize and fight the coronavirus at future dates.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, recently told "The Daily Show" host Trevor Noah that he is "really confident" that recovered coronavirus patients will have immunity.

Fauci added that he'd be "willing to bet anything that people who recover are really protected against re-infection."

Then again, some studies suggest coronaviruses exist in bats as persistent infections, and this property may carry over to the human-infecting strain.

Why it matters: Understanding whether long-term immunity is the norm would have major ramifications for controlling the pandemic and could enable officials to lift social-distancing restrictions for people who have already gotten sick.

How seasonal is the coronavirus?

How seasonal is the coronavirus?

President Donald Trump has said of the coronavirus: "A lot of people think that goes away in April, with the heat that comes in."

The truth is that no one knows, but most experts do not think the virus will simply vanish as temperatures rise.

There is one glimmer of hope, though, that warmer and wetter conditions may at least hinder the virus' spread.

According to unpublished research by a team of scientists in Beijing, China, "high temperature and high relative humidity significantly reduce the transmission of COVID-19, respectively, even after controlling for population density and GDP per capita of cities."

However, because there are so many cases of the new coronavirus, and still so many people who have not yet had it, researchers suspect the disease could become seasonal — at least until a vaccine becomes available.

Why it matters: Knowing how much the novel coronavirus is impacted by changing seasons (or not at all) would help governments around the world better deploy resources to confine its spread.


Are there any safe and effective drugs to treat the coronavirus?

Are there any safe and effective drugs to treat the coronavirus?

There is no FDA-approved treatment for the coronavirus or its symptoms yet. However, there are some promising early candidates.

In February, a group of researchers in France showed in lab results that hydroxychloroquine — a relatively inexpensive inflammation inhibitor that kills malarial parasites and also helps lupus and rheumatoid arthritis patients — may have some effect. Combined with an antibiotic called azithromycin, which may combat opportunistic microbes in the lungs, that effect may be even stronger. Early results from a clinical trial (though one involving just a handful of people) suggest the combo may flatten infections in about a week.

However, clinical studies are still underway, and the drug combination may not be safe or effective for use against COVID-19 for a broad population. (At least one man died after taking a variant of hydroxychloroquine, and his wife said the couple did so following praise for the drug by President Donald Trump.)

Another pharmaceutical that may help is remdesivir, an experimental antiviral drug. But as with the former option, studies are ongoing into its efficacy and safety for coronavirus patients.

All three of the drugs are seeing restrictions lifted for experimental use on COVID-19 patients.

Why it matters: Having tools to slow down or perhaps even stop the coronavirus from harming patients could curtail its spread, reduce suffering, ease the burdens the pandemic is placing on healthcare systems, and save lives.

Will there be a safe and effective vaccine for the coronavirus, and when?

Will there be a safe and effective vaccine for the coronavirus, and when?

At least 10 clinical trials for the novel coronavirus are underway, according to STAT. They each take different approaches, though some only slightly, and there's a good chance at least one should work safely and effectively.

But all of the vaccine candidates are in an early experimental phase — it may take more than a year to prove they work and another 6 months after that to manufacture and distribute them. There's also no guarantee that any of them will work at all.

In the meantime, social distancing — the practice of staying at least 6 feet away from people outside your home — may be the new normal for months.

Why it matters: Developing a vaccine would help the world put an end to the pandemic.


What are the long-term consequences for those who survive COVID-19?

What are the long-term consequences for those who survive COVID-19?

Some of the first people who got the coronavirus and recovered have only been well for a number of weeks. So it's not yet clear what the long-term consequences of weathering a severe bout of COVID-19 might be.

One emerging story from early cases in China is reduced lung function.

"They gasp if they walk a bit more quickly," a top infectious-disease expert said of some survivors, according to the South China Morning Post. He added: "Some patients might have around a drop of 20 to 30% in lung function."

Only time will tell what else, if anything, may affect people who recover from coronavirus infections.

Why it matters: If the coronavirus is found to cause lasting damage to lungs and other organs, governments may be further spurred to take more drastic and rapid actions to control the spread of the disease. There may also be a significant new burden on already strained healthcare systems around the world.

Aria Bendix, Bill Bostock, Andrew Dunn, Holly Secon, and Aylin Woodward contributed reporting to this article.