The 2019 Novel Coronavirus (SARS-CoV-2) is a new virus that emerged in China in late 2019 and quickly jumped into scientific and mainstream news. When facing a potential pandemic, it can be difficult to share information without inducing panic. There’s no doubt that SARS-CoV-2 presents a significant threat to public health, but as with all viruses in their emerging stages, we often find ourselves with more questions than answers. However, through the work of the World Health Organization (WHO), government officials and hardworking scientists worldwide, we can begin to understand some of the details about SARS-CoV-2.
What is SARS-CoV-2?
On December 31, 2019, Chinese health authorities reported an outbreak of lower respiratory infections in Wuhan City, China. All confirmed cases at that point indicated that the outbreak originated at a market selling live poultry and seafood. Those infected first experience fever and severe cough, along with pneumonia and lung lesions. The virus was quickly identified as a novel coronavirus of unknown zoonotic origin.
Coronaviruses get their name from the halo of fringe surrounding their virions, which resemble the solar corona. Notable examples include Severe Acute Respiratory Syndrome (SARS-CoV), which infected over 8,000 individuals and caused 774 deaths in 2003, and Middle East Respiratory Syndrome (MERS-CoV), which has infected almost 2,500 and caused 858 deaths since 2012.
Coronaviruses are notable for infecting animals such as cows, chickens and pigs, in addition to humans. Disease-causing coronaviruses often originate in non-human animals and later leap human populations. SARS-CoV, for example, was eventually traced to civets, which were an intermediate step for the virus originating in a species of bats. At this time, SARS-CoV-2 is also believed to have originated in bats.
Previous reports referred to the virus as “Wuhan Coronavirus,” “Novel Coronavirus” and “2019-nCoV.” The virus was officially named “SARS-CoV-2” by the International Committee on Taxonomy of Viruses on February 11. The disease caused by SARS-CoV-2 is called “COVID-19.”
How bad is it?
The World Health Organization declared a Public Health Emergency of International Concern on January 30. As of March 5, WHO reported 93,090 confirmed cases of COVID-19 worldwide. The vast majority of cases have been in China, but the past two weeks have seen new infections slowing in China and increasing in the rest of the world. Major outbreaks have occurred in South Korea, Italy and Iran, as well as smaller emerging outbreaks in Japan, the United States and parts of Europe. There have been 3,198 deaths worldwide. A live map of confirmed infections and deaths published by Johns Hopkins Center fro Systems Science and Engineering is available here.
According to CDC, COVID-19 symptoms include fever, cough and shortness of breath. The illness is generally considered to be mild, but an NEJM article published February 28, 2020 reports that 16% of cases progress to severe illness, including Acute Respiratory Distress Syndrome. As with seasonal influenza, it appears that people over age 65 or individuals with compromised immune systems are at the greatest risk of severe illness.
In a press briefing on Wednesday, March 4, WHO Director-Gineral Tedros Adhanom Ghebreyesus stated that the global fatality rate is around 3.4%, significantly higher than previous estimates of 2.3%. The fatality rate fluctuates between 0.7-4% locally based on the quality of the health care system. A breakdown of the most at-risk demographics is available from STAT News.
It was previously reported that estimated R0 values ranged between 2 and 3. R0 is a measure of the number of people who will become infected by a single infected individual, and the value helps predict whether a disease will decline or continue spreading. These values still seem to be accurate, and CDC is now stating that global pandemic is likely based on current conditions. According to their situation summary, COVID-19 now meets two of the three criteria to be classified as a pandemic, including community transmission.
There are several factors that give SARS-CoV-2 greater potential for widespread infection. First, it’s a very new disease that only appears to have jumped to humans in the past few months. This means that the whole global population is likely vulnerable, since no one would have the benefit of previous exposure. Second, the relatively low rates of severe illness mean that fewer infected individuals will independently seek medical attention. Many infected people will continue with life as usual, spreading respiratory droplets to everyone they come in contact with. Finally, the period of contagion seems to be exceptionally long, with some estimates as long as 29 days.
What are scientists and health care workers doing about it?
Travel restrictions are now common in most countries, and several countries have instituted mandatory quarantines upon entry from China. Many conferences and events have been canceled, including the annual meeting of the American Physical Society and the South Korean leg of the latest tour by K-Pop sensation BTS.
On January 31, a group of 94 journals signed an open-access pledge for all research related to SARS-CoV-2. The pledge also states that all relevant research will be made available on preprint sites and shared with the WHO. The executive editor of NEJM stated on February 13 that they were receiving up to 20 submissions a day related to SARS-CoV-2. WHO maintains a public database of the latest research that is available here.
In the months since the virus first emerged, several major research developments have contributed to drug and vaccine development efforts. The viral sequence was first published in NEJM on January 24, followed by the first successful culture from patient samples on January 29. The structure of the viral spike was published in Science on February 19.
The virus can be detected using qPCR-based protocols available from CDC and other sources. Testing kits are being supplied by WHO and CDC, though other organizations have released their own kits including the state of New York. On February 25, Promega was recognized by Co-Diagnostics, Inc. for support in manufacturing the new Logix Smart™ COVID-19 Test, which received CE mark approval and is available in Europe as an in vitro diagnostic.
At this time, there are no drugs approved for use against SARS-CoV-2, but several trials are underway. A team based at Emory University announced plans to test a molecule previously shown to inhibit two other coronaviruses against SARS-CoV-2. Another team used Remdesivir, an adenine analog, in the first successful treatment of SARS-CoV-2 in the United States. A team in Singapore is using serum from recovered patients to treat patients in the early stages of the illness, and a patient in Thailand was successfully treated using a combination of HIV and flu drugs. The National Institute of Health has previously stated in a report that they believed a vaccine against SARS-CoV-2 could be available for early human testing within three months. A summary of vaccines currently in development is available here.
The best way to protect yourself from infection is always to practice good hygiene, especially washing your hands with soap and water. Cover your mouth and nose while coughing or sneezing and maintain a safe social distance. There is no need at this time to wear protective face masks, especially given a global shortage of masks for healthcare workers who are most at risk. At this time, the most responsible action for anyone outside of areas with confirmed infections is to stay informed from credible sources and practice good hygiene.