A New Coronavirus, a New Epidemic, Many Open Questions
Latest update: February 26, 2020
The new coronavirus that jumped from some animal to a person in the city of Wuhan at the end of last year has managed, in only a few weeks, to draw huge attention from the media, scientists and the international community. On January 30, the WHO declared the epidemic a public health emergency of international concern (PHEIC).
The epidemic is evolving very fast and with it, the knowledge we have on this new virus. From not knowing anything at beginnings of 2020, the scientific community has managed to isolate it, sequence it, identify it, and develop a diagnostic test.
However, as occurs with every new epidemic, there are many open questions that will be answered as the epidemic evolves and as scientists manage to get a better grasp of the virus’s behaviour.
In this page we will try to provide regular updates on the most relevant information of the virus and the epidemic.
1. What is the New Coronavirus from Wuhan?
The new coronavirus, first called 2019-nCoV and now officially renamed as SARS-CoV2 (the virus) and COVID-19 (the disease), belongs to the family of coronavirus, which owe the name to crown-like spikes on their surface. Most described coronavirus are found in birds or mammals, particularly bats.
The new coronavirus is called SARS-CoV2 because its genetic sequence is very similar to that of SARS, another coronavirus that appeared for first (and only) time in 2002 and caused a pandemic with more than 8,000 infected people and 800 deaths. Another coronavirus that causes severe disease in humans is MERS-CoV, identified for the first time in 2012 in the Middle East and associated with camels.
2. How Did SARS-CoV2 Appear?
The first human cases are all linked to a market in Wuhan that also sells wildlife. Close contact between animals (including people) that do not co-exist normally in nature can favour a virus to acquire the capacity to jump from one host to the other and then spread from person to person. In the case of the new coronavirus, recent analyis show that it could have jumped from bats to pangolins, and from there to humans.
3. How Does COVID19 Spread?
The main route of transmission is thought to be mainly by air, through small droplets produced when an infected person coughs or sneezes. It is also probably transmitted through close contact with body fluids of infected people.
Recent evidence suggests that, in contrast with SARS that was only transmitted by people with symptoms, the new coronavirus can be transmitted even before the onset of symptoms. If this is confirmed, it means that controlling virus transmission will be much more difficult.
COVID-19 can be transmitted from one person to another with relative ease. To date, the WHO estimates that the R0, or basic reproduction number, the virus is somewhere between 1.4 and 2.5, although other estimates give a range between 2 and 3. This means that every infected person can in turn infect 2 to 3 other people, although some “superspreaders” in this epidemic have been found to infect up to 16 people. To control an epidemic, the R0 needs to be below 1.
4. What are the Symptoms of COVID19?
The main symptoms are fever, cough and difficulty to breathe. However, in a small percentage of patients, the first symptoms may be diarrhea and nausea.
The WHO has estimated an incubation period (between infection and symptom onset) of 2 to 10 days, although this is quite a wide range.
Is it dangerous?
The virus causes from mild symptoms to severe respiratory disease (i.e. pneumonia) and death. Most deaths have occurred in people over 65 years of age and that were already suffering from another chronic condition or disease.
Data suggest a case fatality rate (CFR) of around 2% (which means 2 deaths out of every 100 confirmed cases), although it is still too early to give a precise cipher. It could be lower if the number of undiagnosed asymptomatic cases or cases with very mild symptoms turns out to be high. It could increase if the virus mutates. In any case, the case fatality rate seems to be lower than that of SARS (10%) and higher than that of seasonal flu (below 0.01%).
In fact, according to an analysis of all 72,342 cases diagnosed in China as of February 11, the disease is mild for 81% of patients, with an overall CFR of 2.3%
5. How is COVID-19 Treated?
To date, there is no specific vaccine or treatment for COVID-19. The scientific community is working hard to develop a vaccine but, in the best of cases, it won’t be available before several months or even years.
Therefore, the current strategy to deal with this new virus is to avoid contagion (through preventive measures) and treat the symptoms in case of illness.
The basic preventive measures to avoid infection are: wash your hands frequently and cover your mouth when sneezing or coughing.
6. Evolution of the Epidemic*
* Last update: 26/02/2020