The disease appears to have originated from a Wuhan seafood market where wild animals, including marmots, birds, rabbits, bats and snakes, are traded illegally. Coronaviruses are known to jump from animals to humans, so it’s thought that the first people infected with the disease – a group primarily made up of stallholders from the seafood market – contracted it from contact with animals.
Although an initial analysis of the virus that causes Covid-19 suggested it was similar to viruses seen in snakes, the hunt for the animal source of Covid-19 is still on. A team of virologists at the Wuhan Institute for Virology released a detailed paper showing that the new coronaviruses’ genetic makeup is 96 per cent identical to that of a coronavirus found in bats, while an as-yet unpublished study argues that genetic sequences of coronavirus in pangolins are 99 per cent similar to the human virus. Some early cases of Covid-19, however, appear to have inflicted people with no link to the Wuhan market at all, suggesting that the initial route of human infection may pre-date the market cases.
The Wuhan market was shut down for inspection and cleaning on January 1, but by then it appears that Covid-19 was already starting to spread beyond the market itself. On January 21, the WHO Western Pacific office said the disease was also being transmitted between humans – evidence of which is apparent after medical staff became infected with the virus. Since then, evidence of widespread human-to-human transmission outside of China has been well established, making chances of containing the virus much harder.
What exactly is Covid-19?
Coronaviruses are a large group of viruses that are known to infect both humans and animals, and in humans cause respiratory illness that range from common colds to much more serious infections. The most well-known case of a coronavirus epidemic was Severe Acute Respiratory Syndrome (Sars), which, after first being detected in southern China in 2002, went on to affect 26 countries and resulted in more than 8,000 cases and 774 deaths. The number of people infected with Covid-19 has now well surpassed those hit with Sars.
While the cause of the current outbreak was initially unknown, on January 7 Chinese health authorities identified that it was caused by to a strain of coronavirus that hadn’t been encountered in humans before. Five days later the Chinese government shared the genetic sequence of the virus so that other countries could develop their own diagnostic kits. That virus is now called Sars-CoV-2.
Although symptoms of coronaviruses are often mild – the most common symptoms are a fever and dry cough – in some cases they lead to more serious respiratory tract illness including pneumonia and bronchitis. These can be particularly dangerous in older patients, or people who have existing health conditions, and this appears to be the case with Covid-19. A study of 44,415 early Chinese Covid-19 patients found that 81 per cent of people with confirmed infections experienced only mild symptoms. Of the remaining cases, 14 per cent were in a severe condition while five per cent of people were critical cases, suffering from respiratory failure, septic shock or multiple organ failure. In the Chinese study, 2.3 per cent of all confirmed cases died, although the actual death rate is probably much lower as many more people will have been infected with the virus than tested positive.
How far has it spread?
China has borne the brunt of Covid-19 infections (so far). As of March 11, Chinese health authorities had acknowledged over 81,250 cases and 3,253 deaths – most of them within the province of Hubei. On March 17, China recorded just 39 new cases of the virus – a remarkable slowdown for a country which, at the peak of its outbreak in mid-February, saw more than 5,000 cases in a single day.
But while things were slowing down in China, the outbreak started picking up in the rest of the world. There are now confirmed cases in at least 150 countries and territories. Outside of China, Italy has seen the highest number of cases, with 47,035 confirmed infections, mostly in the north of the country, and 4,032 deaths – more than in China. The entire country is now on lockdown after the quarantine covering the north of the country was extended on March 9.
Spain is also in the grip of a significant outbreak. The country has 20,410 confirmed infections and 1,043 deaths – the second-highest number within Europe. There, citizens are under lockdown, with the government shutting all schools, bars, restaurants and non-essential supermarkets down. People are only allowed to leave their homes to buy food or to go to work. Germany has 19,711 cases and 53 deaths, with the state of Bavaria implementing a full lockdown.
Iran, too, is seeing a surge in cases. The country has confirmed at least 1,433 deaths and 19,664 cases. In the US, there have been more than 14,631 cases and 210 deaths – 74 of them in Washington State, which has become the epicentre of the US outbreak.
While the number of new cases continues to rise sharply, people are also recovering from the infection. Globally, 84,960 people have recovered from Covid-19 – about 32 per cent of all of the people who had confirmed infections, although the true number of coronavirus cases will be much higher.
What’s the latest in the UK?
As of March 18, the UK has reported 3,983 confirmed Covid-19 infections and 177 deaths. On March 16, prime minister Boris Johnson led the first daily coronavirus press conference, saying that the government now advised all UK residents to avoid non-essential social contact and travel where possible. On Friday March 20 this was extended to include a shutdown of all bars, pubs, cafes and restaurants in the UK. From the same day all schools in England, Scotland and Wales were shut until further notice. Only vulnerable children, or those who are the sons and daughters of employees in the NHS or other key industries, will be permitted to remain at school.
People who currently live alone are recommended to self-isolate for seven days if they develop a fever or persistent dry cough – the two most common symptoms of coronavirus. For families and other people who live together, the advice is that the entire household should self-isolate if any member develops either of those symptoms. This strategy is part of the government’s ‘delay phase‘ plan to flatten the peak of the virus and reduce the burden on the NHS.
A key part of this plan is shielding those who are most vulnerable to Covid-19: people older than 70, or those who have underlying health conditions. The prime minister said that this shielding may last as long as 12 weeks in order to ensure that the peak of the outbreak has passed, although modelling from Imperial College London suggests that these measures may have to be in place for as long as 18 months. Despite these measures, some have been critical that the government’s stance doesn’t go far enough. Italy and Spain have both in place widespread lockdowns, while South Korea has rolled-out extremely comprehensive testing for many of its population.
The outbreak has also had a serious impact on the UK’s stock market. On March 9 the FTSE 100 fell by more than eight per cent, knocking billions off the value of major UK companies. Cinema changes Odeon, Cineworld and Vue closed their doors while Euro 2020 was also delayed until 2021, which is an added blow to broadcasters, particularly ITV.
What are the symptoms of Covid-19?
Covid-19 shares many of its symptoms with the flu or common cold, although there are certain symptoms common to flu and colds that are not usually seen in Covid-19. People with confirmed cases of Covid-19 rarely suffer from a runny nose, for instance.
The most common Covid-19 symptoms are a fever and a dry cough. Of 55,924 early Chinese cases of the disease, nearly 90 per cent of patients experienced a fever and just over two-thirds suffered with a dry cough. That’s why the UK government is advising anyone with a high temperature or a new, continuous cough to stay at home for seven days or, if they live with other people, for the entire household to isolate for 14 days from the first onset of symptoms.
Other Covid-19 symptoms are less common. Just under 40 per cent of people with the disease experience fatigue, while a third of people cough up sputum – a thick mucus from within the lungs. Other rarer symptoms include shortness of breath, muscle pain, sore throats, headaches or chills. According to the WHO, symptoms tend to appear between five and six days after infection.
What’s happening with a vaccine?
A vaccine for Covid-19 isn’t around the corner. Bringing vaccines to the market is a notoriously slow process and any potential vaccine will have to pass multiple stages of testing for safety and effectiveness. And once we know a vaccine is safe, we will also need to manufacture it at a scale high enough to use across the world. It’s likely that any vaccine is around 18 months away.
That said, there is lots of work being done to develop a vaccine for Covid-19. The pharmaceutical firm Sanofi is trying to build on its already-approved flu vaccine and turn it into something suitable to treat Covid-19. Other approaches – such as one being trialled by the University of Oxford – are focusing on the external spike proteins on the Covid-19 virus as a way to target vaccines.
But accelerating these efforts will require funding. The Coalition for Epidemic Preparedness Innovations (CEPI) has called for $2 billion in funding to support the development of new coronavirus vaccines.
What’s going to happen next?
WHO chief Tedros Adhanom Ghebreyesus has warned that the window of opportunity to contain Covid-19 is “narrowing”. Recent outbreaks in Italy and Iran, which so far have no clear link to China, pose a significant challenge to health authorities trying to stop the spread of the virus.
After initially delaying the decision, on March 11, the WHO declared the Covid-19 outbreak a pandemic. The agency cited the rapid growth of cases outside of China and the global spread of the disease as reasons behind the designation. In January, it also declared the outbreak a “public health emergency of international concern” – the highest category of warning for an infectious disease outbreak.
Since 2009 there have only been five declarations of international public health emergencies: the swine flu pandemic in 2009, a polio outbreak in 2014, the Western Africa Ebola outbreak in 2014, the Zika virus outbreak in 2015 and another Ebola outbreak in the Democratic Republic of the Congo in 2019.
Matt Reynolds is WIRED’s science editor. He tweets from @mattsreynolds1
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