Story at a glance
- There are now more than 800 cases of the new coronavirus in a month and a half since the earliest cases.
- A previous large outbreak of SARS lasted about six months.
- We won’t be able to compare the fatality rates until we know more about the disease and how many people it has affected.
As of today (Jan. 24), there are 846 cases of people with the new Wuhan coronavirus and 26 deaths. This week, Chinese officials blocked travel out of Wuhan by train and plane, new potential cases are under investigation in Canada and Australia, and a second case is confirmed in the U.S. A lot has happened in only the last two weeks, but how does this current coronavirus outbreak in Wuhan compare to the timeline of past large outbreaks, like SARS and MERS?
UPDATE: As of Feb. 3, there were 17,391 cases total and 361 deaths according to the World Health Organization Situation Report. As of Feb. 5, there were 24,554 confirmed cases and 491 deaths. As of Feb. 9, there were 37,558 confirmed cases and 812 deaths. As of March 15, there were more than 156,000 confirmed cases and more than 5800 deaths.
What happened with SARS
The severe acute respiratory syndrome (SARS) outbreak, which happened in 2002-2003, is caused by a coronavirus. But the way things unfolded then is partly why that outbreak was an alarming event, experts say.
The first case is thought to have been reported on Nov. 16, 2002. Health officials didn’t know what it was, and SARS was categorized by its symptoms, which were similar to pneumonia. It took several months for the outbreak to be reported to the World Health Organization (WHO) on Feb. 14, 2003, when there were already more than 300 cases. At that time, Chinese officials were not sure what caused the illness. By March 21, there were cases in 13 countries and 10 deaths.
The entire SARS outbreak lasted about six months, resulting in more than 8,000 cases and killing 774 people. It took months for the virus to be identified as the cause of the illness, and the genome sequence was published in April 2003. Granted that technology for sequencing has advanced since 2003 allowing for faster work, this still means that it took a few months from the first knowledge of the outbreak.
The MERS outbreaks
Middle East respiratory syndrome (MERS) is caused by a coronavirus, named MERS-CoV. It was first identified in Saudi Arabia in Sep. 2012, and about 35 percent of infected patients die from the virus, according to WHO. MERS-CoV doesn’t pass easily from person to person unless there is close contact like physical touch.
By June 2013, there were 55 laboratory-confirmed cases reported to WHO. Cases were reported in Saudi Arabia, Qatar, Jordan and the United Arab Emirates and some infected travelers were reported in the United Kingdom, Italy, France and Tunisia.
In 2015, there was a separate outbreak of MERS-CoV in South Korea. The first patient of the outbreak developed symptoms on May 11, 2015. WHO and the South Korean government estimated that the outbreak ended in July 2015, after about two months. By the end, there were 186 confirmed cases and 38 deaths.
The early days of the Wuhan coronavirus
The illness caused by a new coronavirus in Wuhan, currently being called 2019-nCoV, was first reported to WHO on Dec. 31, 2019 as a “cluster of cases” in Wuhan. The earliest cases were estimated to have started on Dec. 8. The virus’s genetic material, the RNA, was sequenced and made public information on Jan. 10. That’s a relatively quick turnaround time.
This past week, researchers published their analyses of the new coronavirus (Jan. 22) and diagnostic tools for testing people for the virus (Jan. 23). Researchers are sharing what they are learning about the virus much earlier than in past outbreaks.
Another important difference, especially when compared to the SARS outbreak, is the speed to take action, to disseminate warnings and recommendations to the general public and to put restrictions on travel as the number of cases increased. When cases jumped up from 68 on Sunday, Jan. 19 to more than 800 cases on Thursday, Jan. 23, officials put a clamp down on public transportation out of Wuhan.
Looking back at SARS, the fatality rate for SARS varied by age, “less than 1 percent in persons aged 24 years or younger, 6 percent in persons aged 25 to 44 years, 15 percent in persons aged 45 to 64 years, and greater than 50 percent in persons aged 65 years and older,” according to WHO.
So far, the deaths from 2019-nCoV have mostly been in older people, many with existing health problems. However, the most recent death is of a 37-year-old man who is now the youngest fatality in this outbreak. As more reports of cases and deaths come in, we will have to wait to understand how dangerous this virus is and how it compares to past coronavirus outbreaks.
You can follow Chia-Yi Hou on Twitter.