A New Coronavirus, a New Epidemic, Many Open Questions
Latest update: April 5, 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.
COVID-19: Scientific Updates
ISGlobal’s Contribution to the Fight Against COVID-19
How is the Pandemic Affecting Urban Health?
1. What is the New Coronavirus SARS-CoV-2 or COVID-19?
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, it is believed that it jumped from bats to an intermediary mammal host (maybe a pangolin) and from there to humans.
3. How Does COVID19 Spread?
The main route of transmission is by air, through small droplets produced when an infected person coughs or sneezes. It is also transmitted by touching your eyes, nose, or mouth after touching contaminated surfaces. A study in the laboratory found that SARS-CoV-2 can remain viable on some surfaces for a certain time (ranging from a few hours on copper up to one to two days on plastic or steel surfaces). However, this transmission route does not seem to be the most effective.
Recent evidence confirms 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 or even by asymptomatic people. This considerably hinders containment efforts aimed at limiting viral spread.
COVID-19 can be transmitted from one person to another with considerable 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.
How is COVID-19 diagnosed?
SARS-Cov2 infection occurs mainly in the respiratory tract. This is why the current diagnostic tests, which rely on the amplification of viral gene sequences by PCR or on the detection of viral proteins (rapid diagnostic tests) must be done on nose or throat swabs.
Another type of diagnosis test that is currently under development is one that detects antibodies against the virus. In this case, a blood sample is sufficient. This test has the advantage of detecting not only individuals with active or recent infection, but also those who were previously exposed to the virus and are therefor immune to it.
4. What are the Symptoms of COVID-19?
The main symptoms are fever, cough and difficulty to breathe. However, in a small percentage of patients, the first symptoms may be diarrhea, nausea or headache. Loss of semall and taste seems to be frequent among infected individuals and could be among the first signs of disease.
The WHO has estimated an incubation period (between infection and symptom onset) of 2 to 14 days, although most people develop symptoms between 5 and 7 days.
Is it dangerous?
The virus causes from mild symptoms to severe respiratory disease (i.e. pneumonia) and death. The great majority of deaths have occurred in people over 65 years of age and that were already suffering from another chronic condition or disease. Hypertension and diabetes seem to be the highest risk factor for severe disease and death and this could be in part due to the drugs taken for treating these conditions. In contrast, children are considerably less susceptible to developing the disease, although they do seem to get infected. Their role in spreading the virus remains to be determined.
According to an analysis of all 72,342 cases diagnosed in China as of February 11, the disease is mild for 81% of patients, 14% develop severe symptoms, and around 4-5% are critical.
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 (to date, there is no evidence this is happening). In any case, the case fatality rate is lower than that of SARS (10%) and could be around ten times higher than that of seasonal flu (below 0.1%).
A recent study estimates that the adjusted case fatality rate in China was 1.4% for confirmed cases and 0.66% when considering infected but undiagnosed cases.
5. How is COVID-19 Treated?
To date, there is no specific vaccine or treatment for COVID-19. To gain time, the scientific community is working hard to test antiviral drugs that already exist in the market and that could have an effect on the new virus. Some exemples are the antiviral drug remdesivir (originally tested for Ebola virus) and an HIV treatment (lopinavir / ritonavir), as well as chloroquine, an old antimalarial drug.
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.
Areas with high viral transmission can also recommend the adoption of social distancing measures, such as cancelling mass gatherings, promoting telework, avoiding unnecessary travel, and keeping a distance of at least 1 meter with other people, among others. These measures contribute to slowing viral spread within the community and avoid overwhelming health systems.
A vaccine soon?
Two vaccines (one based on messenger RNA and developed by a US-based company, and another one based on virus subunits and developed by China) have started to be tested in humans. For the moment, they are in the first phase of the clinical trial (to see if they are safe). Experts agree that we will not have an available vaccine before 12 months, in the best of cases.
6. Evolution of the Epidemic
Last update: 05/04/2020 at 4.59 PM. Data from Johns Hopkins University & Medicine.
Photo: An empty street due to social distancing measures in Leeds, UK. Dan Burton on Unsplash. This article has been written...Environmental Health, Coronavirus, Emerging Viruses 03.04.2020
Over the last weeks, confirmed cases and deaths from COVID-19 have soared globally, with these figures expected to continue increasing for some...Environmental Health, Coronavirus, Emerging Viruses 25.03.2020
[This article has been written by Carlos Chaccour and Adelaida Sarukhan, in collaboration with Joe Brew and Pau Rubio] Over the last weeks,...Coronavirus, Emerging Viruses 17.03.2020
The risk is that the efforts undertaken by Europe, USA and other developed nations will be limited to themselves. It would be foolish to face a...Coronavirus, Emerging Viruses 16.03.2020
In the middle of the 19th century, the General Hospital in Vienna had two maternity clinics with very different outcomes in terms of mortality: ...Communications, Emerging Viruses 30.04.2019
The Ebola outbreak in DRC, the wildfires in California, the first high-level meeting on tuberculosis and the #Metoo movement were some of the...Communications, Emerging Viruses 19.12.2018
Interview with Dawoh Peter Lansana (better known as Brother Peter), director of the Saint Joseph’s Catholic Hospital of Monvrovia, Liberia,...Ebola, Emerging Viruses 05.12.2018
[This article has been published in Spanish in Planeta Futuro-El País] The global health community is still working on addressing and...Ebola, Emerging Viruses 14.05.2018
[Written for Big Vang (La Vanguardia) by Adelaida Sarukhan , PhD in immunology and scientific writer at ISGlobal, Jose Muñoz , ISGlobal...Epidemiology, Immunization, Emerging Viruses 17.03.2018
Vector-borne diseases make up 17% of all infectious diseases worldwide , causing 700,000 deaths every year and around 250,000 if we exclude...Malaria, Zika, Emerging Viruses 15.09.2017
In a recent study, we used climate forecasts to predict the risk of a dengue epidemic Decision-makers in resource strained settings face...Environmental Health, Emerging Viruses 10.07.2017
[This article has been written by Adelaida Sarukhan , PhD in Immunology scientific writter at ISGlobal, and Joaquim Gascon , Head of...Epidemiology, Emerging Viruses 05.09.2016
They are the most beautiful mosquito species we have: The Aedes family . Small, dark with bright white spots and stripes. But that is only...Zika, Emerging Viruses 17.08.2016
[This article is written by Adelaida Sarukhan (ISGlobal) and Jose Muñoz (ISGlobal-Hospital Clínic) and it has been published in Spanish...Zika, Emerging Viruses 01.06.2016
The Ebola epidemic in West Africa was declared a public health emergency of international concern by the WHO in August 2014. Since then ,...Ebola, Emerging Viruses 21.03.2016
The recent declaration of the zika virus as a “global emergency” by the WHO as a consequence of the epidemic in Latin America...Epidemiology, Emerging Viruses 09.02.2016