The COVID-19 (short for coronavirus disease 2019) outbreak was first identified in Wuhan, the capital city of China’s central Hubei province, in December 2019. The virus, which causes a respiratory illness, has since spread rapidly to more than 110 countries, across all continents except Antarctica. Among the most severely affected countries to date are Iran, Italy and South Korea. Two days ago, on March 11, 2020, the World Health Organization officially declared COVID-19 a pandemic. As the virus leaves governments and populations in a state of confusion and uncertainty, Sarah Rifky spoke with virologist and science communicator Islam Hussein to answer some of the frequently asked questions about the virus.
Sarah Rifky: What makes the coronavirus so infectious? How is it different from other epidemics in the way it spreads? How does it compare to influenza, SARS or swine flu, for example?
Islam Hussein: It’s always relative. We have criteria to measure the extent of the spread. There are technical terms used by epidemiologists to measure how contagious a certain virus is. If you compare this new virus with other viruses that we know from human history, you will find it is not as contagious, comparatively speaking. For example, a virus like measles is highly contagious — one infected child at a school will infect 18 others, on average. This is what we call R0 [a basic reproduction number] — it indicates how many people are likely to be infected from an infected individual. In the case of SARS-CoV-2, the virus that causes the COVID-19 disease, what we know so far is based on preliminary calculations for these values. These numbers are calculated based on the data collected during the outbreak. So far, estimates have ranged from 2.5 – 3 to 3 – 4. This refers to how many people could be infected from a single infected individual.
If you compare it to other diseases we describe as contagious, it is not that bad. It does not spread with the same efficiency as viruses like measles. If you compare this to SARS (severe acute respiratory syndrome), which appeared in 2002–2003, you will find quite similar numbers. What is new about novel coronavirus is that it seems capable of replicating in both the upper and lower respiratory tracts. Our respiratory system is divided into two major regions: the upper part, which includes the nose, throat and larynx, and the lower part, which is made up of the trachea and the lungs. It seems like the new virus replicates in both parts, while SARS could mainly replicate in the lungs.
If you have a virus that replicates in the lungs, it is more difficult to expel — more difficult for it to be excreted by coughing. And if it replicates in the upper respiratory tract, then everything that comes out is loaded with a high concentration of the virus.
How did coronaviruses start? And can you explain to us the crossover of the virus from animals to humans?
We know a lot about the coronavirus family as a whole. We have gathered plenty of information on this virus family since the outbreak of SARS back in 2002. This family includes a number of viruses that infect both animals and humans. Animals act as a natural reservoir, meaning they get infected but don’t show symptoms. There are four members of the coronavirus family that had been infecting humans but the symptoms were not severe, more like those of a common cold. Those four types have existed in humans for a very long time.
But in 2002, a more aggressive version started to appear: SARS CoV. Then in 2012, the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) appeared. The third, SARS CoV-2, appeared last December. The information that we’ve accumulated throughout the past 17 years tells us that this particular group lives in animals. We have prior knowledge that bats have acted as a natural reservoir for coronaviruses. In the case of the original SARS-CoV in 2002, we identified bats as a source, then it jumped — probably through an intermediate host, because bats usually live far from people — to humans. In SARS-CoV, the intermediate host was the civet — an animal that looks like a cat but is not a feline. Civets are eaten in China and are available at markets. The virus moved from bats to civet cats, and from civet cats to humans. In MERS, it moved from bats to camels. Camels are important in the Middle East, especially in the Gulf region. Their meat and milk are consumed and the animal is used recreationally, in races for example — camels have important cultural value in the Arab world in general.
When we talk about the new coronavirus, this knowledge is important for our understanding of how the disease develops in context. Do we have specific clues [or evidence] that points us to bats being the origin of this virus? Yes, because the new coronavirus is nearly 96 percent homologous with the previous coronavirus that was isolated and studied in 2013. So do we have any clues or confirmation that the virus originates with bats? Yes, because in 2013, the coronavirus was isolated from bat samples and sequenced in labs.
So, what is the suspected intermediate host for the novel coronavirus?
We are still not sure. There are some indications that the infection might have moved from bats to pangolins [a type of scaly anteater], another popular source of meat in China whose scales are also used in traditional Chinese medicine. There is some indication that pangolins may have gotten the virus from bats because the virus may be transferred through bat droppings. So pangolins might have picked up some fecal material while feeding off the ground, picking up the virus with it. It seems that the virus may have undergone some genetic changes in pangolins that allowed it to jump to humans. Further adaptation may have also occured in humans that facilitated human-to-human transmission.
How much do we know about the coronavirus and its genomic structure? Does the virus change?
There may be some changes to the virus, or it could have been a recombination. When two related, but not identical viruses, infect the same cell, there is a chance that their genetic material mixes together, producing offspring slightly different from either parent virus.
Does this mean the virus is constantly evolving genetically?
Yes, absolutely. There are so many mechanisms for this continuous evolution. One is the polymerase enzyme, which copies the genetic material and makes a lot of mistakes it can’t correct. The result is what we call mutations.
Is the current outbreak of the new coronavirus an epidemic or pandemic? What is the difference?
An epidemic is when you have a rapidly spreading infection in a well-defined place like a state or a city. So, when it started in Wuhan, it was an epidemic. A pandemic is an illness that spreads across a wide geographical area or globally. Its criteria is spreading in two countries or more on top of the country of origin and via community transmission unrelated to travel. The World Health Organization has not declared it a pandemic. But all these things have political considerations and an impact on people. They were a little bit late in declaring it a public health emergency of international concern. Now they are hesitant to declare it a pandemic, but they will. [Hours after this interview was conducted, the WHO officially declared COVID-19 a pandemic on March 11.]
Do you think this type of epidemic is increasingly tipping over into a pandemic, historically speaking, in recent years? Because, in 17 years, we’ve witnessed the outbreak of SARS, followed byH1N1 (swine flu) and MERS, is there an acceleration or increase in this type of virus?
I don’t think so. It will vary case by case. For example, in 2009, H1N1 virus, one of the influenza viruses, led to a pandemic. This is not so far in the past. I don’t think it is getting worse. I think people just forget. People get distracted with so many things and they forget how nasty it can become if we are not prepared or don’t have the right tools to control infections and treat or vaccinate people, and so on.
How come babies and children have the lowest risk of mortality from the coronavirus? Aren’t their immune systems less developed than adults? And why are schools being closed if they are “immune” to it?
I don’t think we have a clear answer yet. It’s either that children do not get exposed to the disease in the first place after contracting the virus, or they are exposed to it, but they present a very mild form of the disease — almost no symptoms — to the point that even their families don’t seek medical attention. There was an asymptomatic case of a 10-year-old kid; but, luckily, to date there have been no fatal cases in children. This is good news. While we don’t know exactly what’s going on — and I don’t think anyone has a clear and exact answer — this [children presenting a different immune response] is not new: Chickenpox presents mild symptoms in children but has severe one in adults. We have precedents, it is not completely out of the blue.
As a parent and a scientist, why do you think they are closing schools?
Well, because we are not sure. We have a lot of open questions. For example, if children get a mild form of the disease, do they transmit it to other people in the school? We don’t know. When people close schools, they are just taking precautionary measures against the spread of the disease. We will know more in the coming few weeks and months, but so far everyone is trying their best to limit the spread. Closing schools and universities and asking people to take online courses, which you’re seeing now, is another precautionary measure to limit the spread.
There are several reports that say a vaccine and other treatments are in development. Why are they so hard to develop?
We have seen this in the past. SARS happened in 2002 and there is no vaccine for it. MERS happened in 2012 and we don’t have a vaccine for it either. It is difficult for two reasons. One, it takes a long time to test for safety and efficacy. Safety comes first. So it takes so many years in the lab — first on animals, then clinical trials with humans, which take a lot of time. It takes years, maybe 10 years to come up with something and until it is finally approved by regulatory agencies like the FDA in the US. The second reason is that nothing is going to happen if there is no commercial interest. These vaccines are developed by companies that want to develop a product that will be sold in the market and give them a return on their investment. They assess the situation and they decide whether it is worth investing. This is the brutal reality. No one does this for free or as charity.
So, is there anyone interested in developing a vaccine for the coronavirus?
Over the past 17 years, we have had two major coronaviruses. One appeared only briefly and the second, MERS, still exists in small numbers. Despite these two previous outbreaks, we still don’t have one, which tells you there is no commercial interest. But there might be now, after SARS CoV-2.
Is there any comparative data between cases in which infected individuals easily recovered versus those with complications and death?
I think we know a little bit about risk factors. One of them is age — rates are higher in older age brackets. This indicates that the presence of other pre-existing conditions and chronic diseases more prevalent among the elderly, coupled with the infection, leave the body with a lower chance of beating the disease.
There is also a correlation with smoking. In China, they found that the mortality rate in males is almost double that of females. They couldn’t understand why. But when they looked at the percentage of smokers, they found 52 percent of males in China smoke compared to just two percent of females. So it could be that smoking-related health conditions could make things worse.
In your assessment, what would be the ideal way of preventing the pandemic globally?
One of the key features of this new virus is that there are many asymptomatic carriers. This both good news and bad news. The good news is that the majority of cases, more than 80 percent, are mild. The bad news is that these people live their lives normally. They go to work, they use transportation, they travel. So there is a high likelihood that these people with mild or no symptoms will unknowingly spread the infection. I think this is a crucial piece of information that may explain why it is spreading so fast.
Preventing the spread of the virus happens on two levels: individually and governmentally. On the individual level, to avoid infection, we advise people to follow the basic rules of hygiene like washing your hands and sneezing into your elbow. Hand sanitizers and other soaps that have lipid solvents deactivate the virus. Alcohol-based disinfectants or those common in households are okay [and good to use at home]. Staying away from large gatherings and avoiding unnecessary travel as airports and airplanes are places that facilitate viral transmission. At the government level, we are already witnessing what is going on: Saudi Arabia cancelled umra. Some countries have halted or limited air travel, and others have introduced quarantines. All of this limits the spread of infection. But does this stop it completely? No, because we now live in a time in which the movement of people has never been easier. We also have more than 100 countries that have reported cases. Governments identify the infected person and they identify, isolate and treat them. But what we are facing is that we are having a hard time identifying the infected.
Do you think we are all going to get it eventually?
I am prepared for this scenario, yes. I don’t agree with people who say so-and-so percentage of people will get it. I don’t think anyone has a clue. But of course there is a chance many people would get infected. There are many unknowns. But what we know for sure is that it is spreading very rapidly.
In your assessment, do you think the general response to this situation in Egypt has been adequate?
Yes. I know we [Egyptians] have a sense of humor and we like to joke about everything, but this is very serious. Some people like to mock statements and actions by Health Ministry officials on social media. I feel sorry for these people. I know how hard and challenging it is for any health care system, including the US. The US is screwing up big time by not providing enough testing. The UK health minister is now infected. I know how critical the situation is, and I know these people don’t get any sleep because of this huge responsibility. Some negative stuff might happen, but this does not mean people should make it into a mockery, because it is not. It is very hard for them and I think they are doing their best. There is nothing up till now that indicates they are not being transparent. All indications suggest the Health Ministry is dealing with the situation transparently. This is something we should appreciate. I have never interacted with them and I don’t know them personally, but I think they cooperate well with the WHO and they try to deal with the situation within their limited resources. So we should not be adding to their hardships.