Health officials around the world continue to battle an outbreak of respiratory disease, first detected in the central Chinese city of Wuhan in December. The causative agent was traced to a novel coronavirus, dubbed SARS-CoV-2, which has now infected more than 75,000 people and claimed over 2,000 lives.
The spate of illness was first reported to the World Health Organization on New Year's Eve and in the following weeks was linked to a family of viruses known as coronaviruses, the same family responsible for the diseases SARS and MERS, as well as some cases of the common cold. On Feb. 11, WHO and other organizations agreed to name the new illness COVID-19 (for "coronavirus disease 2019").
A special WHO committee declared a public health emergency on Jan. 30, citing "the potential for the virus to spread to countries with weaker health systems." Human-to-human transmission has been confirmed, including in the US, and authorities around the world have limited travel and enforced quarantines to guard against the spread.
Some of the world's largest tech firms have been adversely affected by the outbreak, shutting down stores and factories in China. Barcelona's Mobile World Congress, the world's largest phone trade show, took the unprecedented step of cancelling the entire show on Feb. 12 due to growing concerns over the spread of the coronavirus.
The Diamond Princess cruise ship, in lockdown in the port of Yokohama since Feb. 3 for a two-week quarantine period due to coronavirus infection, has reported over 540 confirmed cases of COVID-19. The US announced on Feb. 15 it would be evacuating passengers from the stricken vessel and Australia followed suit on Monday. Fourteen of the 340 American passengers evacuated from the vessel tested positive before boarding planes to the US. On Tuesday, the British government announced it would evacuate 74 citizens via plane in the next two or three days.
Electronics giant Apple announced on Monday it would now miss its revenue guidance for the March quarter, as the virus slows work in China. "Worldwide iPhone supply will be temporarily constrained," Apple said, after production facilities were "ramping up more slowly" than anticipated.
The situation continues to evolve as more information becomes available. We've collated everything we know about the novel virus, what's next for researchers and some of the steps you can take to reduce your risk.
Coronaviruses belong to a family known as Coronaviridae, and under an electron microscope they look like spiked rings. They're named for these spikes, which form a halo or "crown" (corona is Latin for crown) around their viral envelope.
Coronaviruses contain a single strand of RNA (as opposed to DNA, which is double-stranded) within the envelope and, as a virus, can't reproduce without getting inside living cells and hijacking their machinery. The spikes on the viral envelope help coronaviruses bind to cells, which gives them a way in, like blasting a door open with C4. Once inside, they turn the cell into a virus factory -- the RNA and some enzymes use the cell's molecular machinery to produce more viruses, which are then shipped out of the cell to infect other cells. Thus, the cycle starts anew.
Typically, these types of viruses are found in animals ranging from livestock and household pets to wildlife such as bats. Some are responsible for disease, like the common cold. When they make the jump to humans, they can cause fever, respiratory illness and inflammation in the lungs. In immunocompromised individuals, such as the elderly or those with HIV-AIDS, such viruses can cause severe respiratory illness, resulting in pneumonia and even death.
Extremely pathogenic coronaviruses were behind the diseases SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome) in the last two decades. These viruses were easily transmitted from human to human but were suspected to have passed through different animal intermediaries: SARS was traced to civet cats and MERS to dromedary camels. SARS, which showed up in the early 2000s, infected more than 8,000 people and resulted in nearly 800 deaths. MERS, which appeared in the early 2010s, infected almost 2,500 people and led to more than 850 deaths.
On Feb. 11, the WHO named the new disease COVID-19. "Having a name matters to prevent the use of other names that can be inaccurate or stigmatizing," Tedros Adhanom Ghebreyesus, director-general of the WHO, said during a briefing. "It also gives us a standard format to use for any future coronavirus outbreaks."
The Coronavirus Study Group, part of the International Committee on Taxonomy of Viruses, was responsible for naming the novel coronavirus itself. According to a preprint paper uploaded to bioRxiv on Feb. 11, the virus will be known as SARS-CoV-2. The group "formally recognizes this virus as a sister to severe acute respiratory syndrome coronaviruses (SARS-CoVs)," the species responsible for the SARS outbreak in 2002-2003. The virus itself was originally given a placeholder name of "2019-nCoV."
The virus appears to have originated in Wuhan, a Chinese city about 650 miles south of Beijing that has a population of more than 11 million people. The Huanan Seafood Wholesale Market, which sells fish, as well as a panoply of meat from other animals, including bats, snakes and pangolins, was implicated in the spread in early January.
Prestigious medical journal The Lancet published an extensive summary of the clinical features of patients infected with the disease stretching back to Dec. 1, 2019. The very first patient identified had not been exposed to the market, suggesting the virus may have originated elsewhere and been transported to the market, where it was able to thrive or jump from human to animal and back again. Chinese authorities shut down the seafood market on Jan. 1.
Markets have been implicated in the origin and spread of viral diseases in past epidemics, including SARS and MERS. A large majority of the people so far confirmed to have come down with the new coronavirus had been to the Huanan Seafood marketplace in recent weeks. The market seems like an integral piece of the puzzle, but researchers continue to test and research the original cause.
An early report, published in the Journal of Medical Virology on Jan. 22, suggested snakes were the most probable wildlife animal reservoir for SARS-CoV-2, but the work was soundly refuted by two further studies just a day later, on Jan. 23.
Here's a study refuting the evidence for the snake as a #coronavirus reservoir. Suggests that the closest coronavirus relatives are found in bats (bats were also considered the reservoir for SARS in 2003)https://t.co/gRHWIdwMFX
"We haven't seen evidence ample enough to suggest a snake reservoir for Wuhan coronavirus," said Peter Daszak, president of nonprofit EcoHealth Alliance, which researches the links between human and animal health.
"This work is really interesting, but when we compare the genetic sequence of this new virus with all other known coronaviruses, all of its closest relatives have origins in mammals, specifically bats. Therefore, without further details on testing of animals in the markets, it looks like we are no closer to knowing this virus' natural reservoir."
Another group of Chinese scientists uploaded a paper to preprint website biorXiv, having studied the viral genetic code and compared it to the previous SARS coronavirus and other bat coronaviruses. They discovered the genetic similarities run deep: The virus shares 80% of its genes with the previous SARS virus and 96% of its genes with bat coronaviruses. Importantly, the study also demonstrated the virus can get into and hijack cells the same way SARS did.
The ant-eating pangolin, a small, scaled mammal, has also been implicated in the spread of SARS-CoV-2. According to the New York Times, it may be one of the most trafficked animals in the world and it was sold at the Huanan Seafood Market. The virus likely originated in bats but may have been able to hide out in the pangolin, before spreading from that animal to humans.
All good science builds off previous discoveries -- and there is still more to learn about the basic biology of SARS-CoV-2 before we have a good grasp of exactly which animal vector is responsible for transmission -- but early indications are the virus is similar to those seen in bats and likely originated from them.
On Feb. 12, Chinese health authorities reported a jump in the amount of cases and deaths in Hubei, the epicenter of the outbreak. Over 13,300 new cases were recorded in Hubei alone, an increase of 700% over the previous day. Chinese authorities had adopted a new clinical method for confirming cases Wednesday, which sees them add "clinically diagnosed cases" to the count, which could help patients receive treatment sooner, according to CNN.
A cruise ship, the Diamond Princess, stationed off the Japanese port of Yokohama has been put into quarantine after a passenger traveling onboard was found to be infected with SARS-CoV-2. Around 3,700 passengers and crew are on the ship until Feb. 19, and the total number of cases on board has reached at least 542 as of Feb. 18 -- the highest anywhere outside China. On Feb. 15, the US said it would evacuate Americans from the ship and Australia followed suit on Monday.
In the US, 15 cases have been confirmed: eight in California, two in Illinois and one each in Arizona, Massachusetts, Texas, Wisconsin and Washington state. Canada has seven confirmed cases. An additional 14 cases were confirmed after evacuation from the Diamond Princess.
You can track the spread of the virus with this handy online tool, which is collating data from a number of sources including the CDC, the WHO and Chinese health professionals.
On Feb. 7, Li Wenliang, the 34-year-old Chinese doctor who spoke out about the rising cases of pneumonia in an online chat room during the early days of the outbreak, died as a result of COVID-19. A day later, the first known American death from the illness was announced: A US citizen in Wuhan.
On Feb. 15, France's health minister reported that a Chinese tourist had succumbed to coronavirus at a Paris hospital a day earlier, the first death outside Asia. Two other deaths have been recorded outside China, one in the Philippines, the other in Japan.
The death toll surpassed that of the SARS epidemic (severe acute respiratory syndrome) on Feb. 8. That outbreak killed 774 people. On Feb. 9, the death toll surpassed 900, overtaking the death toll of MERS (Middle East respiratory syndrome), a similar coronavirus that has killed 858 people since 2012.
Those two viruses have a higher death rate, with SARS-CoV killing about 10% of those infected and MERS-CoV killing about 34%, whereas this virus, SARS-CoV-2, hovers at around 2% to 3%.
The death toll still pales in comparison to that of influenza -- the flu -- which, through the first four weeks of 2020, had killed 1,210 in the US alone, according to the CDC.
A pedestrian in the city of Wuhan, China. The virus appears to have originated in Wuhan's Huanan Seafood Wholesale Market.
The Chinese Center for Disease Control and Prevention dispatched a team of scientists to Wuhan to gather information about the new disease and perform testing in patients, hoping to isolate the virus. Their work, published in the New England Journal of Medicine on Jan. 24, examined samples from three patients. Using an electron microscope, which can resolve images of cells and their internal mechanics, and studying the genetic code, the team were able to visualize and genetically identify the novel coronavirus.
Understanding the genetic code helps researchers in two ways: It allows them to create tests that can identify the virus from patient samples, and it gives them potential insight into creating treatments or vaccines.
Additionally, the Peter Doherty Institute in Melbourne, Australia, was able to identify and grow the virus in a lab from a patient sample. They announced their discovery on Jan. 28. This is seen as one of the major breakthroughs in developing a vaccine and provides laboratories with the capability to both assess and provide expert information to health authorities and detect the virus in patients suspected of harboring the disease.
This is one of the major questions researchers are still working hard to answer. The first infections were potentially the result of animal-to-human transmission, but confirmation that human-to-human transmission was obtained in late January.
The University of Minnesota's Center for Infectious Disease Research and Policy reported that health workers in China had been infected with the virus in late January. During the SARS epidemic, this was a notable turning point, as health workers moving between countries were able to help spread the disease.
"The major concern is hospital outbreaks, which were seen with SARS and MERS coronaviruses," said C. Raina MacIntyre, a professor of global biosecurity at the University of New South Wales. "Meticulous triage and infection control is needed to prevent these outbreaks and protect health workers."
On Feb. 5, Chinese state media reported a newborn had been diagnosed with COVID-19 just 30 hours after birth, opening up the potential for mother-child transmission. Viruses can be transmitted through the placenta, but experts say it's too early to tell whether this is the case with the novel coronavirus, which is "unlikely" to be passed on in the womb.
A handful of viruses, including MERS, can survive for periods in the air after being sneezed or coughed from an infected individual. Although recent reports suggest the novel coronavirus may be transmitted in this way, the Chinese Center for Diseases Control and Prevention have reiterated there is no evidence for this. Writing in The Conversation on Feb. 14, virologists Ian Mackay and Katherine Arden explain "no infectious virus has been recovered from captured air samples."
In Wuhan, authorities rushed to build a thousand-bed hospital to treat coronavirus patients as the province struggles with hospital bed shortages. It began taking patients on Feb. 4.
China shut down Wuhan to reduce the spread of the virus, canceling transportation leaving the city starting at 10 a.m. Jan. 23. The travel restrictions were extended to four other cities (Huanggang, Ezhou, Chibi and Zhijiang) later that day, and constraints were announced in eight more cities on Jan. 24 -- impacting more than 35 million people.
The restrictions were enforced during a busy travel period for China, when citizens typically travel for the Lunar New Year. Major public events Chinese capital Beijing were canceled, and both Beijing's Forbidden City and Shanghai's Disneyland closed down from Jan. 25. All of the restrictions and closures will last indefinitely.
The scale of the global efforts to contain the disease is immense. Hong Kong closed many public facilities on Jan. 28 and has prevented traveling between mainland China. The US announced sweeping border control measures at 20 ports of entry and has been considering cancelling flights to and from the outbreak epicenter in Wuhan. Esports tournaments have been postponed, Shanghai and Hong Kong Disneyland has closed, Olympic women's soccer tournaments have been moved entirely, and McDonald's has shuttered thousands of locations across China where the virus is spreading.
British Airways on Jan. 29 suspended all flights to and from mainland China "for the next few days," a spokesperson confirmed via email. American Airlines and Delta are also suspending service to mainland China, though Delta will continue to operate flights until Feb. 5 for customers looking to exit China. The national airline in Australia, Qantas, announced the suspension of flights from Sydney to Beijing and Sydney to Shanghai from Feb. 9. New Zealand's carrier, Air New Zealand, suspended daily flights to Shanghai on Feb. 1.
Cruise ships have also begun denying passengers, with Royal Caribbean announcing Feb. 7 that it will deny entry to "all holders of China, Hong Kong and Macau passports, regardless of residency." It's also barring anyone who has travelled to China, Hong Kong or Macau in the 15 days prior to boarding; and anyone who has come within six feet of someone from China, Hong Kong or Macau 15 days prior; and anyone with fever or low blood oximetry. Norwegian Cruise Line is denying entry to anyone who has been through China, Hong Kong and Macau within 30 days prior to the cruise, and to anyone holding a passport from those places.
On Jan. 31, US Secretary of Health and Human Services Alex Azar declared a public health emergency citing the nation's intention to protect and respond to the outbreak, while noting "the risk to Americans remains low." Australia and Japan followed suit. On Feb. 4, Britain's Foreign Office and the French Foreign Ministry warned citizens to evacuate China to lower their risk of infection.
On Feb. 12, GSMA, the organization responsible Mobile World Congress, said it's calling the event off due to the number of companies withdrawing following the outbreak of coronavirus. Several notable tech companies -- including LG, ZTE, Samsung, Amazon, Ericsson, Nvidia, AT&T and others -- had already decided to scale back their presence or skip the show all together.
Speaking to the media on Feb. 17, Shigeru Omi, the chief director of the Japan Community Health Care Organization, suggested the Olympics could be disrupted or even cancelled, depending on how the virus continues to spread and evolve over the next few months.
A widely shared Twitter thread by Eric Feigl-Ding, a Harvard University epidemiologist, suggests the new coronavirus is "thermonuclear pandemic level bad" based on a metric known as the "r nought" (R0) value. This metric helps determine the basic reproduction number of an infectious disease. In the simplest terms, the value relates to how many people can be infected by one person carrying the disease. It was widely criticized before being deleted.
Infectious diseases such as measles have an R0 of 12 to 18, which is remarkably high. The SARS epidemic of 2002-2003 had an R0 of around 3. A handful of studies modeling the COVID-19 outbreak have given a similar value with a range between 1.4 and 3.8. However, there is large variation between studies and models attempting to predict the R0 of novel coronavirus due to the constantly changing number of cases.
In the early stages of understanding the disease and its spread, it should be stressed these studies are informative, but they aren't definitive. They give an indication of the potential for the disease to move from person-to-person, but we still don't have enough information about how the new virus spreads.
"Some experts are saying it is the most infectious virus ever seen -- that is not correct," MacIntyre said. "If it was highly infectious (more infectious than influenza as suggested by some) we should have seen hundreds, if not thousands of cases outside of China by now, given Wuhan is a major travel hub."
China has suggested the virus can spread before symptoms present. Writing in The Conversation on Jan. 28, MacIntyre noted there was no evidence for these claims so far but does suggest children and young people could be infectious without displaying any symptoms. This also makes airport screening less impactful, because harboring the disease but showing no signs could allow it insidiously spread further.
As the virus has continued to spread, it's easy to get caught up in the fear and alarmism rampantly escalating through social media. There is misinformation and disinformation swirling about the effects of the disease, where it's spreading and how. Experts still caution the virus appears to be mild, especially in comparison to infections by other viruses, like influenza or measles, and markedly lower death rates than previous coronavirus outbreaks.
On Jan. 30, the World Health Organization declared a public health emergency of international concern over the coronavirus outbreak. Tedros Adhanom Ghebreyesus, the director-general of the WHO, said the organization is working with national and international public health partners to get the outbreak under control.
The WHO also issued recommendations to prevent the spread of the virus and ensure a "measured and evidence-based response."
"To the people of #China & to all of those around the