How does coronavirus compare with previous global outbreaks?

Matt Woodley

19/02/2020 4:58:45 PM

Coronavirus – COVID-19 – has infected more than 88,000 people since it was first reported in late December, resulting in at least 3000 deaths.

Number of COVID-19 cases and deaths
COVID-19 has infected more than 75,000 people since it was first reported in late December, resulting in at least 2000 deaths.

Initially the overwhelming majority of cases were restricted to mainland China, in particular Hubei province, but a surge in cases has seen infections reported in 66 other countries and regions, along with 131 deaths.
The disease, officially named COVID-19, is thought to be more easily spread than its predecessor SARS, but possesses a lower mortality rate. Slightly less than half of all confirmed cases have recovered so far, while 18% were in a serious or critical condition at the time of publication.
World Health Organization (WHO) spokesperson Tarik Jašarević recently estimated the COVID-19’s R naught (the number of other people one sick person is likely to infect on average) is around 2–2.5, whereas at least one study has suggested it could be as high as 3.11. Based on the number of confirmed deaths and cases, it has a case fatality rate (CFR) of around 2.65%.
The WHO is yet to declare a pandemic, but did label it a Public Health Emergency of International Concern (PHEIC) and upgraded the global risk of the coronavirus outbreak to ‘very high’, its top level of alert, following confirmation of sustained human-to-human transmission outside of China.
Prior to COVID-19, two other coronaviruses – SARS-CoV and MERS CoV – also generated worldwide concern due to their global reach and the number of deaths they caused.
SARS (severe acute respiratory syndrome) is thought to have originated in a Chinese ‘wet market’. Although more deadly than COVID-19 – it has a CFR of 14–15% – most cases of human-to-human transmission occurred in healthcare settings and it only made its way to 26 different countries before being contained.
Its estimated R naught during the initial phase of the epidemic was 2.9, but the implementation of control measures reduced it to 0.4 in the final months of the outbreak.
Overall, SARS is thought to have killed 774 people and infected 8098 between November 2002 and July 2003.

There have been multiple outbreaks of MERS (Middle East respiratory syndrome) since it was first identified in 2012.
Around 80% of cases have been reported in Saudi Arabia; however, its presence has been reported in 26 other countries, including South Korea, which recorded 186 cases and 36 deaths between May and July 2015.
MERS has a far greater CFR than COVID-19 at 34.4%, but each infected person only infects one additional person, making it much less contagious. To date, there have been 2519 laboratory-confirmed cases of infection with MERS-CoV and 866 deaths.
Other global health emergencies
The Kivu Ebola outbreak in the Democratic Republic of Congo (DRC) was the most recent PHEIC prior to the WHO’s COVID-19 declaration.
Beginning on 1 August 2018 in the region of Kivu in eastern DRC, the outbreak infected more than 2500 people and claimed nearly 1700 lives before the WHO declared a global health emergency on 17 July 2019. As of 11 February 2020, there have been 3432 cases and 2249 deaths.
Unlike COVID-19, the outbreak has essentially been contained within one country – only neighbouring Uganda has been affected as well (four cases, all fatalities).
The ongoing emergency is the second Ebola epidemic in the past six years, with the WHO also declaring a PHEIC in 2014 in response to the West African outbreak, which claimed 11,323 lives between December 2013 and June 2016.
The majority of the 28,646 confirmed cases occurred in Liberia, Sierra Leone and Guinea.
Ebola only spreads through direct contact, such as such as through broken skin or mucous membranes in the eyes, nose, or mouth, and is considered less easily transmissible than COVID-19, which is reflected in its R naught (R1.71–2.02). However, it is much more deadly, with an average CFR of 50%.
The H1N1 influenza pandemic of 2009 is thought to have infected 11–21% of the world’s population. It resulted in between 151,000 and 575,400 deaths, but had a CFR of less than 0.1%.
The pandemic began in early 2009 and started to taper off by May 2010, before the WHO announced its end on 10 August 2010.
Deemed an ‘extraordinary event’ by the WHO’s International Health Regulations Emergency Committee, the global eradication of polio was deemed to be at risk with small numbers of cases in Afghanistan, Pakistan, and Nigeria.
It remains an ongoing PHEIC, with cases of wild polio still found in Afghanistan and Pakistan as recently as October 2019.
Zika virus
The fourth-ever PHEIC was declared in response to a widespread epidemic of Zika fever, caused by the eponymous virus, in Brazil. The epidemic began in early 2015 and spread to other parts of South America, as well as several islands in the Pacific and Southeast Asia.
The WHO declared a global health emergency in February 2016 due to evidence that the virus could cause birth defects, as well as neurological problems. It spreads through mosquito bites, through pregnant women to their foetus, sexual intercourse and potentially blood transfusions.
The RACGP has more information on coronavirus available on its website.
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This article was updated to reflect the increasing global number of confirmed coronavirus cases and deaths.

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Dr Steven Jaye Skov   20/02/2020 9:14:19 AM

Is it not worth noting that according to the WHO situation report the death rate outside of China is 0.32 percent and inside China but not in Hubei province is 0.67 percent? Still significant but much less than 2.5 percent overall and nearly 3 percent in Hubei. Provides some better perspective in assessing the risk to individuals here?

Dr Greg Saville   20/02/2020 11:31:37 AM

This is a really helpful article. It puts this current coronavirus outbreak in perspective. Thanks.

Dr Mark Frederick Fletcher   2/03/2020 10:28:41 AM

The CFR for coronavirus is between 2.5-4%. It should be noted that there is a delay from being deemed a confirmed case and actually dying from the virus. This delay on average is about 7-10 days. As a result, it can seem that in other parts of the world, the CFR is low but that number will continue to rise. This is reflected on the ground, as it takes quite a long time for people to die of viral pneumonia and the vast majority of case reports suggest that the illness worsens towards the END OF THE SECOND WEEK. Another important comment is that the serious complication rate is about 20%. This is the proportion of people who will require hospitalisation. Of those, a quarter or 5% of overall cases will require intensive case, most likely positive-pressure ventilation. To put this into perspective, seasonal flu has a serious complication rate of only 1%. Health resources are going to become exhausted very rapidly.