The emergence and rapid increase in cases of coronavirus disease 2019 (COVID-19), a respiratory illness caused by a novel coronavirus, pose complex challenges to the global public health,research and medical communities. We’ll look over following topics in this article:
- What is the novel coronavirus SARS-CoV-2?
- Origin of the novel coronavirus
- How was the virus transmitted?
- Signs and symptoms of coronavirus disease 2019 (COVID-19)
- Causes, treatment and prevention of COVID-19
- The impact of the disease
- Ongoing researches for the invention of COVID-19 vaccine
It was in December last year and news started to emerge that a coronavirus that specialists had never before seen in humans had begun to spread among the population of Wuhan, a large city in the Chinese province of Hubei.
Since then, the novel coronavirus has spread to other countries, both in and outside Asia, leading authorities to describe this as an outbreak. At the end of January this year, the World Health Organization (WHO) declared the situation to be a public health emergency. Now the disease has spread worldwide and took a pandemic mood.
Generally, Coronaviruses are a family of viruses that can cause illnesses such as the common cold, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).
Now the latest coronavirus has been identified as the cause of a disease outbreak in China and the virus is known as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease it causes is called coronavirus disease2019 (COVID-19).
To date, the novel coronavirus has been responsible for 81,000 infections in China and 12,000 across 61 other world countries. The virus has so far caused 3,100deaths worldwide. It has already causes 7 deaths in the USA.
However,what do we really know about this virus? And how is it likely to affect the global population?
HealthOrg have contacted the WHO, used the information that public health organizations have offered, and looked at the newest studies that have featured in peer-reviewed journals to answer these and other questions from our readers.
What is the novel coronavirus SARS-CoV-2?
The novel coronavirus called SARS-CoV-2 is a coronavirus that causes coronavirus disease 2019 (COVID-19). Coronaviruses, in general, are a family of viruses that target and affect mammals’ respiratory systems. According to their specific characteristics, there are four main kinds (genera) of Coronaviruses,which are called alpha, beta, delta, and gamma.
Generally, most of the Coronaviruses only affect animals, but a few can also pass to humans. Those that are transmissible to humans belong to only two of these genera: alpha and beta.
Those two types of Coronaviruses have previously caused global outbreaks. The first of these was the SARS coronavirus responsible for severe acute respiratory syndrome (SARS) which first started spreading back in 2002, also in China. The SARS virus epidemic primarily affected the populations of mainland China and Hong Kong, and it died off in 2003.
The other one was the MERS coronavirus — or Middle East respiratory syndrome coronavirus which emerged in Saudi Arabia in 2012. This virus has affected at least 2,494 people since then.
Origin of the novel coronavirus
It is thought that first human become infected with the novel coronavirus via the contact of the infected animal.
And some of the most common carriers are bats, although they do not typically transmit Coronaviruses directly to humans. Instead, the transmission might occur via an “intermediary” animal, which will usually though not always be a domestic one.
In past the SARS coronavirus spread to humans via civet cats, while the MERS virus spread via dromedaries. However, it can be difficult to determine the animal from which a coronavirus infection first starts spreading.
But in the case of the new coronavirus, initial reports from China tied the outbreak to a seafood market in central Wuhan. As a result, local authorities closed down the market on January 1.
Later assessments have since suggested that this market was unlikely to be the single source of the coronavirus outbreak, as some of the people infected with the virus had not been frequenting the market.
Scientists have not yet been able to determine the true source of the virus or even confirm whether there was a single original reservoir.
One of the WHO official’s spokesmen emphasized: “We don’t yet know what the specific source of SARS-CoV-2 was. Researchers in China are studying this but have not yet identified a source.”
How was the virus transmitted?
Though the viruses originated in animals, the transmission of the new coronavirus from person to person can occur, though some questions about its transmission remain unanswered.
As stated by the WHO spokespeople who responded to queries, “researchers are still studying the exact parameters of human-to-human transmission.”
“In Wuhan at the beginning of the outbreak, some people became ill from exposure to a source, most likely an animal, carrying the disease. This has been followed by transmission between people,” they explained, adding:
“As with other Coronaviruses, the transmission is through the respiratory route,meaning the virus is concentrated in the airways (nose and lungs) and can pass to another person via droplets from their nose or mouth, for example. We still need more analysis of the epidemiological data to understand the full extent of this transmission and how people are infected.”
In a press briefing from February 6, WHO consultant Dr. Maria Van Kerkhove said that, for now, “We do know that mild individuals shed virus, we know that severe individuals shed virus. We know that the more symptoms you have, the more likely you are to transmit.”
In their “Q&A on Coronaviruses,” the WHO states that “the risk of catching COVID-19 from someone with no symptoms at all is very low.”
In an interview for the JAMA Network also broadcast on February 6 Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, said that based on data that they have received from Chinese specialists, the new coronavirus “incubation period is probably between 5 and 6 maybe closer to 5 days.“
So the virus likely takes about 5–6 days to give rise to symptoms once it has infected a person.
Although the WHO note that experts estimate that the new virus’s incubation period may last anywhere between 1 and 14 days, they suggest in their coronavirus Q&A section that the most likely duration is about 5 days.
Comparison between novel Coronavirus and other Coronaviruses
Scientists from Chinese institutions were able to use state of the art genome sequencing tools to identify the DNA structure of the novel coronavirus.
It has emerged that SARS-CoV-2 is most similar to two bat coronaviruses known as bat-SL-CoVZC45 and bat-SL-CoVZXC21 its genomic sequence is 88% the same as theirs.
The same study shows that the new virus’s DNA is about 79% the same as that of the SARS coronavirus and approximately 50% like that of the MERS virus.
Recently,a study by researchers in China suggested that pangolins may have been the initial propagators of SARS-CoV-2, as its genomic sequence appeared to be 99%like that of a coronavirus specific to these animals.
Since then, however, other specialists have cast doubts over this idea, citing inconclusive evidence.
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Signs and symptoms of coronavirus disease (COVID-19)
As stated by the Centers for Disease Control and Prevention (CDC), the main symptoms of COVID-19 are fever, cough, and shortness of breath.
Like previous Coronaviruses, the novel coronavirus causes respiratory disease, and the symptoms affect respiratory health.
Generally, signs and symptoms of COVID-19 may appear 5 to 14 days after exposure and can include the followings :
• runny nose
• Shortness of breath
• Sore throat
• exacerbated asthma
The severity of COVID-19 symptoms can range from very mild to severe. People who're older or have existing medical conditions, such as heart disease, may be at higher risk of serious illness. This is similar to what is seen with other respiratory illnesses, such as influenza.
“Current information suggests that the virus can cause mild, flu-like symptoms, as well as more severe disease. Most patients seem to have mild disease, and about 20% appear to progress to more severe disease, including pneumonia, respiratory failure, and, in some cases, death,”WHO spokespeople told HealthOrg.
Moreover,in their press briefing from February 27, WHO officials also pointed out that a runny nose is not usually a symptom of COVID-19.
In an official WHO Q&A session, Dr. Van Kerkhove explained that as the symptoms of COVID-19 can be very generic, it can be difficult to distinguish between them and the symptoms of other respiratory infections.
To understand exactly what a person is dealing with, she said, specialists test viral samples, checking to see whether the virus’s DNA structure matches that of SARS-CoV-2 or not.
“When someone comes in with a respiratory disease, it’s very difficult if not impossible initially to determine what they’re infected with. So, because of this, what we rely on are diagnostics molecular tests,” said Dr. Van Kerkhove.
Contact your doctor right away if you have COVID-19 symptoms and you've possibly been exposed to the virus. Tell your doctor if you've recently traveled internationally. Call your doctor ahead to tell him or her about your symptoms and recent travels and possible exposure before you go to your appointment.
It's unclear exactly how contagious the new coronavirus disease 2019 CCOVID-19) is.It appears to be spreading from person to person among those in close contact.It may be spread by respiratory droplets released when someone with the virus coughs or sneezes.
Risk factors for COVID-19 appear to include:
- Recent travel from or residence in China
- Close contact with someone who has COVID-19 such as when a family member or health care worker takes care of an infected person
If you develop symptoms of COVID-19,contact your doctor. Tell him or her about any recent travels, especially international travel. Also let your doctor know if you've had close contact with anyone who has been diagnosed with COVID-19.
Your doctor may take samples,including a sample of saliva (sputum), a nasal swab and a throat swab, to send for testing.
There are currently no targeted, specialized treatments for infections resulting from the new coronavirus. When doctors detect a SARS-CoV-2 infection, they aim to treat the symptoms as they arise.
Treatment is directed at relieving symptoms and may include:
• Pain relievers
• Cough syrup or medication
• Fluid intake
If your doctor thinks you can be treated at home, he or she may give you special instructions, such as to isolate yourself as much as possible from family while you're sick and to stay home fora period of time. If you're very ill, you may need to be treated in the hospital.
In the WHO Q&A, Dr. Van Kerkhove explained that“because this is a new virus, we don’t have specific treatments for that virus.But because this virus causes respiratory disease, those symptoms are treated.“
“Antibiotics won’t work against a virus,” she also emphasized.
Although there is no vaccine available to prevent infection with the new coronavirus,you can take steps to reduce your risk of infection. WHO and CDC recommend following the standard precautions for avoiding respiratory viruses:
- Wash your hands often with soap and water, or use an alcohol-based hand sanitizer.
- Cover your mouth and nose with your elbow or tissue when you cough or sneeze.
- Wear protective masks. Masks should cover the nose and mouth and be tightly secured.
- Avoid touching your eyes, nose and mouth if your hands aren't clean.
- Avoid close contact with anyone who is sick.
- Avoid sharing dishes, glasses, bedding and other household items if you're sick.
- Clean and disinfect surfaces you often touch.
- Stay home from work, school and public areas if you're sick.
CDC doesn't recommend that healthy people wear a face mask to protect themselves from respiratory illnesses, including COVID-19. Only wear a mask if a healthcare provider tells you to do so.
However,WHO guidelines state that people need only do this if they are caring for someone who has COVID-19. People should thoroughly wash their hands before putting on a new mask, make sure that they dispose of used masks appropriately,and clean their hands once again after removing them.
WHO also recommends that you:
- Avoid eating raw or undercooked meat or animal organs.
- Avoid contact with live animals and surfaces they may have touched if you're visiting live markets in areas that have recently had new coronavirus cases.
Official Who prevention guidelines suggest that to avoid infection with the coronavirus,individuals should apply the same best practices for personal hygiene that they would to keep any other virus at bay.
Moreover, if you're planning to travel internationally, first check travels advisories. You may also want to talk with your doctor if you have health conditions that make you more susceptible to respiratory infections and complications.
The impact of COVID-19
Many people are worried about whether the current outbreak will evolve into a pandemic, and public worries have become amplified by the CDC’s telebriefing from February 25, which asked U.S. citizens to be prepared for that possibility.
However,WHO officials argue that declaring a COVID-19 pandemic may not be a constructive approach to the current public health emergency.
In a declaration on February 26, WHO’s director-general, Dr. Tedros Adhanom Ghebreyesus stated that “using the word pandemic carelessly has no tangible benefit, but it does have significant risk in terms of amplifying unnecessary and unjustified fear and stigma, and paralyzing systems.”
Many questions also remain about how SARS-CoV-2 compares with other viruses in terms of its rates of infection and mortality.
In response to questions about this, the WHO spokespeople told HealthOrg that “this is a new disease, and our understanding is changing rapidly. We will continue to analyze information on both current and any new cases.”
“We don’t yet know many details about the mortality rate from SARS-CoV-2, and studies are ongoing now. With MERS, we know that approximately 35% of reported patients with [MERS coronavirus] infection have died. For SARS, WHO estimated that the case fatality ratio of SARS ranges from 0% to 50% depending on the age group affected, with an overall estimate of case fatality of 14% to 15%.” WHO spokespeople
So far, the number of infections and deaths that COVID-19 has caused is also smaller than the number resulting from recent outbreaks of particularly harmful influenza viruses, such as swine flu (H1N1).
“OnH1N1, From April 12, 2009, to April 10, 2010, the CDC estimated there were 60.8million cases, 274,304 hospitalizations, and 12,469 deaths in the United States due to the (H1N1)pdm09 virus. Additionally, the CDC estimated that151,700–575,400 people worldwide died from (H1N1)pdm09 virus infection during the first year the virus circulated,” the WHO spokespeople told.
According to recent assessments, SARS-CoV-2 seems to be more infectious than other coronaviruses such as those that cause SARS and MERS but less likely to lead to death.
Some estimates suggest that the death rate of the new coronavirus is in the range of2–3%, but there are no official numbers in this regard, as it is hard to tell how the outbreak will develop.
In the WHO press briefing from February 6, WHO officials reiterated that the people most at risk of experiencing severe illness due to a SARS-CoV-2 infection are older adults and individuals who have other health conditions that compromise their immune system.
“Being over 80 is the highest risk factor” for SARS-CoV-2 related death, WHO officials also said in the press briefing.
Other reports note that very few children have become infected with the new coronavirus and that men might be more at risk than women.
Ongoing researches for the invention of COVID-19 vaccine
In the same Q&A, Dr. Van Kerkhove noted that “there are treatments that are in development” for the new coronavirus. Over the years,she said, “many treatments have been looked at to treat other coronaviruses,like the MERS coronavirus.”
“And hopefully, those treatments can also be useful for the novel coronavirus,” she continued.
There are currently clinical trials underway to find a treatment and a vaccine against the MERS coronavirus, which, if successful, could lay the groundwork for a SARS-CoV-2 vaccine and COVID-19 treatment.
Some scientists are also experimenting with using antiretroviral therapy, which is a treatment for HIV, against the new virus. But why might these kinds of treatments hold any promise when it comes to fighting off this coronavirus?
According to some studies, the combination of antiretroviral drugs that scientists are experimenting with lopinavir andritonavir is able to attack a specialized molecule that HIV and coronaviruses both use to replicate.
Another allegedly promising avenue is using baricitinb a drug that doctors use to treat arthritis against the new coronavirus. The researchers who came up with this idea explain that it is likely thatSARS-CoV-2 can infect the lungs by interacting with specific receptors present on the surface of some lung cells.
But such receptors are also present on some cells in the kidneys, blood vessels,and heart. Baricitinib, the researchers say, may be able to disrupt the interaction between the virus and these key receptors. However, whether or not it will really be effective remains to be seen.
Ina press briefing from February 5, WHO officials explained investigators’ preference for experimenting with existing drugs in fighting off the new coronavirus.
Such drugs, they said, have already gained official approval for use against other specifications, meaning that they are largely safe. As a result, they need not go through the extensive series of preclinical trials and clinical trials that new drugs require, which can take a very long time indeed.
Important sites for more information
To get more information about the new coronavirus outbreak and for extensive guidelines about best practices when dealing with the virus, here are a few international resources that you can access:
- WHO info hub
- CDC info hub
- European Centre for Disease Prevention and Control (ECDC) info hub
- Australian Government Department of Health resources
- BMJ latest news
- The Lancet resource center
- Nature article collection
HealthOrg will continue to follow any developments regarding this global health issue, and we will make sure that we keep our readers updated and well-supplied with accurate information.