/Novel coronavirus: What we know so far

Novel coronavirus: What we know so far

The current outbreak of COVID-19 has sparked global anxiety and concern. What are the realities of the pandemic? We investigate.

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The emergence of the novel coronavirus has led to many urgent questions.

This article was updated on May 21, 2020

In December 2019, reports emerged 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 virus has spread to other countries, inside and outside of Asia, leading the World Health Organization (WHO) to declare this as a pandemic.

To date, the novel coronavirus — called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) — has been responsible for millions of infections globally, causing hundreds of thousands of deaths. The highest number of deaths has occurred in the United States.

What do we really know about this virus? To what extent is it likely to affect the global population?

Medical News Today have contacted the WHO, collected information from public health organizations, and looked into the newest studies in peer reviewed journals to answer these and other questions from our readers.

SARS-CoV-2 is a coronavirus that causes coronavirus disease 2019 (COVID-19). Coronaviruses are a family of viruses that target and affect mammals’ respiratory systems. According to their specific characteristics, there are four main ranks, or genera, of coronavirus: alpha, beta, delta, and gamma.

Most of these 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.

Only two coronaviruses have previously caused global outbreaks. The first of these was the SARS coronavirus — responsible for severe acute respiratory syndrome (SARS) — which started spreading 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 was the MERS coronavirus — responsible for Middle East respiratory syndrome (MERS) — which emerged in Saudi Arabia in 2012. The virus has affected at least 2,494 people since then.

When humans contract a coronavirus, it typically happens due to contact with an infected animal.

Some of the most common carriers are bats, though 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.

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 starts spreading among humans.

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, 2020.

However, later assessments have suggested that this market was unlikely to be the single source of the coronavirus outbreak, as some people with the virus early on had no connection with it.

Specialists have not yet been able to determine the true source of the virus or even confirm whether there was a single original reservoir.

When MNT contacted the WHO for comment, their spokespeople 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.”

Although it likely originated in animals, SARS-CoV-2 mainly seems to travel from person to person. However, some questions about its transmission remain unanswered.

According to WHO spokespeople, “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.

“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.”

The WHO state that “The risk of catching COVID-19 from someone with no symptoms at all is very low. However, many people with COVID-19 experience only mild symptoms. […] It is, therefore, possible to catch COVID-19 from someone who has, for example, just a mild cough and does not feel ill.”

According to the Centers for Disease Control and Prevention (CDC), some recent studies suggest that people may still spread COVID-19 if they are not showing symptoms.

This means that people should adopt careful hygiene practices and engage in physical distancing — even around people who do not appear to be sick.

The CDC also report that SARS-CoV-2 spreads easily among people. They state that the virus “is spreading more efficiently than influenza, but not as efficiently as measles, which is highly contagious.”

People may begin to experience symptoms 2–14 days after exposure to the virus.

The CDC recommend that all people wear cloth face masks in public places where it is difficult to maintain a 6-foot (2-meter) distance from others. This will help slow the spread of the virus from asymptomatic people and people who do not know that they have contracted it. People should wear cloth face masks while continuing to practice physical distancing. Instructions for making masks at home are available here. Note: It is critical that surgical masks and N95 respirators are reserved for healthcare workers.

Researchers from Chinese institutions have used 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: 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% the same as 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 among humans, as its genomic sequence appears to be 99% like that of a coronavirus specific to these animals.

Since then, however, other specialists have cast doubts about this idea, citing inconclusive evidence.

Like other coronaviruses, the novel coronavirus causes respiratory disease, and the symptoms affect a person’s respiratory health.

According to the CDC, the symptoms of COVID-19 can include:

  • a cough
  • shortness of breath or difficulty breathing
  • a fever
  • chills
  • muscle pain
  • a sore throat
  • a new loss of taste or smell

Less commonly, symptoms may include gastrointestinal symptoms, such as nausea, vomiting, or diarrhea.

A study published in The Lancet reports that around 81% of people with COVID-19 have mild symptoms and do not require hospitalization.

“Current information suggests that the virus can cause mild flu-like symptoms, as well as more severe disease. Most [people] 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 MNT.

In an official WHO Q&A session, Dr. Maria Van Kerkhove explained that because 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.

“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.

The WHO officially changed their classification of COVID-19 from a public health emergency of international concern to a pandemic on March 11, 2020.

In a declaration, the WHO’s director general, Dr. Tedros Adhanom Ghebreyesus, stated that:

“[The] WHO has been assessing this outbreak around the clock and we are deeply concerned, both by the alarming levels of spread and severity and by the alarming levels of inaction.

We have therefore made the assessment that COVID-19 can be characterized as a pandemic.

‘Pandemic’ is not a word to use lightly or carelessly. It is a word that, if misused, can cause unreasonable fear, or unjustified acceptance that the fight is over, leading to unnecessary suffering and death.

Describing the situation as a pandemic does not change [the] WHO’s assessment of the threat posed by this virus. It doesn’t change what [the] WHO is doing, and it doesn’t change what countries should do.”

The global implications have been severe. Many countries have closed schools and are recommending that people work from home when they can. Some countries have completely locked down their international borders and are discouraging travel unless it is deemed essential.

In the U.S., the White House is advising people to avoid social gatherings of more than 10 people. Individual states have introduced their own measures to try to deal with the situation. Find out about state and local guidance here.

Meanwhile, many questions remain about how SARS-CoV-2 compares with other viruses, in terms of its rates of infection and mortality.

Reported mortality rates vary from country to country. The COVID-19 case fatality rate in the U.S. appears to be around 6%.

In response to questions about this, WHO spokespeople told MNT 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.”

“With MERS, we know that approximately 35% of reported patients with [MERS coronavirus] infection have died. [The] WHO estimated that the case fatality ratio of SARS ranges from 0–50%, depending on the age group affected, with an overall estimate of case fatality of 14–15%.”

According to research, 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.

The CDC report that the groups most at risk of experiencing severe illness due to SARS-CoV-2 are adults aged 65 or older and individuals of any age who have other health conditions that compromise their immune systems.

Other reports note that very few children have contracted the new coronavirus. However, a recent preliminary study — not yet peer reviewed or published in a journal — claims that children actually face the same risk of infection as adults, and the CDC affirm this.

On May 15, the WHO released a commentary about a health issue known as multisystem inflammatory condition, which has recently been reported in children and adolescents and which may have links with COVID-19.

The condition has features similar to those of Kawasaki disease and toxic shock syndrome.

Multisystem inflammatory condition is rare. Researchers are still investigating its causes and the possible connection with COVID-19.

Concerning COVID-19 in adults, some reports suggest that males might be more at risk than females, though neither the WHO nor the CDC consider male sex to be a risk factor.

Although no published scientific reports have investigated the susceptibility of pregnant women to COVID-19, the CDC note that:

“Pregnant [women] have had a higher risk of severe illness when infected with viruses from the same family as [SARS-CoV-2] and other viral respiratory infections.”

The CDC also recommend that infants born to women with suspected or confirmed COVID-19 be put into isolation.

Mother-to-child transmission is unlikely during pregnancy. A very small number of babies have tested positive for the virus, but it is not clear whether they contracted the virus before or after birth.

The WHO report that pregnant women with COVID-19 symptoms should receive priority access to diagnostic tests.

On April 21, the Food and Drug Administration (FDA) approved the use of the first COVID-19 home testing kit. Using the cotton swab provided, a person can collect a nasal sample and mail it to a designated laboratory for testing.

They specify that the test kit is authorized for use by people whom healthcare professionals have identified as having suspected COVID-19.

Official WHO prevention guidelines suggest that in order to avoid contracting the new coronavirus, people should use personal hygiene practices that can keep any virus at bay.

Experts believe that SARS-CoV-2 transmits through respiratory droplets. The CDC recommend maintaining a distance of at least 6 feet, or 2 meters, from other people to avoid contact with these droplets.

There is currently no strong evidence that the virus transmits through food. The CDC say that transfer from food packaging is possible but that the risk is likely to be very low. They do not believe that this is the main way that the virus spreads.

For general safety, wash the hands with soap and water for at least 20 seconds at a time before preparing or eating food.

Regarding protective masks, the CDC recommend wearing a cloth face covering when out in public, such as when going to the grocery store. This is to slow the spread of the virus and prevent people who do not know that they have the infection from transmitting it.

Face coverings should cover the nose and mouth and fit very securely. They should include multiple layers of fabric and allow for unrestricted breathing. When removing the covering, be careful not to touch the eyes, nose, or mouth. Wash the hands immediately after removing it.

Wash cloth face coverings regularly in the washing machine.

People can learn how to make face coverings at home here.

There are currently no targeted, specialized treatments for mild or moderate COVID-19. When doctors detect a SARS-CoV-2 infection, they generally aim to treat the symptoms as they arise.

On the May 1, 2020, the FDA issued emergency approval allowing healthcare professionals to use an antiviral drug called remdesivir to treat severe COVID-19.

There is limited information about the safety and effectiveness of remdesivir for COVID-19, but a recent trial suggests that it can shorten the recovery time in some people. Learn more here.

It is important to note that antibiotics do not work against any viral infection.

Dr. Van Kerkhove noted that “There are treatments that are in development” for the new coronavirus. Over the years, she added, “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.

Clinical trials are underway to find treatment and a vaccine to protect the body from the MERS coronavirus. If these are successful, they could lay the groundwork for a SARS-CoV-2 vaccine and COVID-19 treatment.

On May 1, based on the results of a clinical trial, the FDA gave emergency approval for doctors to use remdesivir, an antiviral drug, to treat severe COVID-19.

Researchers are also testing whether hydroxychloroquine and chloroquine, prescription drugs that treat malaria and some inflammatory conditions, could prevent and treat COVID-19.

According to a press release from May 14, the National Institute of Allergy and Infectious Diseases (NIAID) is funding a trial to look at whether hydroxychloroquine in combination with the antibiotic azithromycin could prevent hospitalization and death due to COVID-19.

Other drugs, including antiretroviral drugs for treating HIV, are also under investigation.

Another approach that could be promising involves baricitinib, an arthritis drug.

The researchers involved explain that SARS-CoV-2 can likely infect the lungs by interacting with specific receptors on the surfaces of some lung cells. 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, the drug’s effectiveness against COVID-19 remains to be seen.

Meanwhile, a press release on May 8 announced the trial of a COVID-19 treatment regimen involving both remdesivir and baricitinib. This trial is also being sponsored by the NIAID.

Investigators prefer to experiment with existing drugs. This is because these drugs have already gained official approval for other uses, indicating that they are likely to be safe. As a result, the drugs do not need to go through the extensive series of preclinical and clinical trials that new drugs require, which can take a very long time.

For more information about the ongoing pandemic and for detailed guidelines, here are a few international resources:

MNT will continue to report on any developments, making sure that our readers are well-supplied with accurate, up-to-date information.