Coronavirus COVID-19

Coronavirus COVID-19: Facts and self-care

Please note: this page was created and maintained during an early phase of the pandemic as a source of reliable information. We are no longer updating this page, although many of the links remain useful.

Created 7 March 2020, last updated 5 April 2020. Written by OPIS team members Nell Watson, Manu Herrán and Jonathan Leighton. Please send suggestions or comments to


  • Summary
  • About the coronavirus that causes COVID-19
  • Symptoms
  • How to protect yourself and others from being infected
  • What to do if you become sick
  • Resources and current data



This page pools together what we believe is reliable, useful information about the new coronavirus, how to protect yourself and others, and what to do if you get infected. We also provide references with further information, and we are updating with new facts and advice.

We do not want people to panic - this virus is not the apocalypse (although in hard-hit places in northern Italy that is exactly how some people are describing it). Contrary to the views of sceptics who see constant media coverage and large-scale quarantining and event cancellations as fear-mongering – it does represent a serious, imminent threat to the lives and wellbeing of many people. It is having a devastating effect in Italy, with one doctor writing, "The war has literally exploded and battles are uninterrupted day and night." If the worst-case scenarios take place, this will mean a very large number of people suffering and dying globally. Older and more vulnerable people do not deserve this fate because those less vulnerable consider themselves relatively safe.

You can substantially reduce the risks to yourself and others by preparing and taking the precautions mentioned on this page, including self-isolation while the virus is still spreading. This detailed article describes the huge discrepancy between reported cases and true cases due to the lag in detection, and the urgency for governments to implement social distancing and lockdowns in regions affected by the coronavirus until the number of infections is brought under control. Although we may be stuck with this virus until a vaccine is available, we need to do whatever we can to ensure sufficient medical capacity to treat people with serious symptoms, including those who cannot breathe without medical assistance.

This blog post from 19 March gives a good overview of how we can tackle the virus intelligently without paralysing our societies. This article from 18 March explains "why Singapore’s coronavirus response worked – and what we can all learn."

The chart below from @Datagraver shows the progression of cases in some of the most-affected countries in Europe and North America, starting at 1 case per million as the first day, as of 19 March 2020. Most countries are showing a similar trend to Italy, with a lag of a few weeks, due to slowness in implementing aggressive, preventative measures.

About the coronavirus that causes COVID-19

The new coronavirus (officially SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), is not a flu virus. It is far more lethal than the seasonal flu virus, which has an overall mortality rate of about 0.1%. (ref) Current estimates suggest it is ca. 20x more lethal, though this number could drop as we get better data on the total number of people infected with mild cases. At a minimum it is 5-6x more lethal, assuming patients can get adequate medical care. As is the case for the flu, the risk goes up substantially with age (see bar chart below), and those with existing health conditions (e.g. cardiovascular, diabetes, respiratory) are more vulnerable to dying (see second bar chart below). But even relatively young, healthy adults are finding themselves hospitalised and in need of mechanical ventilation. Smokers are more vulnerable. Young children seem to be spared from the worst effects, though they might still transmit the virus, and there might be some unknown lingering or latent effects. Severe cases in all age groups need hospitalisation to reduce mortality.

We are still learning about the virus, and even reputable organisations and government agencies are sometimes providing conflicting information about transmissibility and safety measures. But we know that it is highly contagious and potent. It can potentially travel through the air for several meters and linger on objects for several days, though frequently it will not survive more than several hours. It appears to spread most easily from person to person when people are in close contact with one another (2 metres/6 feet) and through respiratory droplets produced when an infected person coughs or sneezes. (ref 1, ref 2) But there is evidence that it can stay in the air for 30 minutes and travel up to 4.5 metres, according to a Chinese study that examined infection of passengers in a bus. (ref) There is also evidence that it can be transmitted via contaminated surfaces, and probably also fecal matter.

Each person who gets it will likely infect 2-3 others, on average, without social distancing. The number of confirmed cases outside of China is currently (as of 14 March 2020) doubling every ca. 3 days in many countries with a significant number of cases, including Spain, France, Germany, Switzerland, US, UK, Norway; 5 days in Italy; and 13 and 14 days in South Korea and Singapore, respectively. (ref) Since the initial numbers were low, many people thought that the threat was being exaggerated, but within weeks the situation has changed dramatically. This is a feature of exponential growth (see this excellent explanatory video). Between 20-70% of the population of most countries could eventually become infected if rapid testing and social distancing measures fail to contain growth. We may need to manage the spread of the virus until a vaccine is developed and mass produced.

An explosion of cases may overwhelm hospital systems and intensive care units. This has already been happening in Italy in early March 2020. This could mean that patients with a severe form of the disease – or indeed, any other acute, life-threatening condition – may not get the urgent medical treatment they need. This would likely lead to a dramatic increase in death rates, and also dramatically increased suffering, including from respiratory failure. This is a critical reason to try to slow the spread of the virus as much as possible. (See graph below.)

As the virus has a long incubation period, typically around 5 days but in some cases longer than 2 weeks, it is very difficult to contain. Although it initially appeared that people with symptoms are more likely to spread it to others – there were even doubts whether it can be spread before symptoms appear – it is now clear that asymptomatic transmission (when people still appear healthy and feel fine but are shedding the virus) is not only possible, but may well be a major factor in its spread. (ref) In fact, according to the referenced article,  Maria Van Kerkhove, head of the World Health Organization’s emerging diseases and zoonoses unit, said that preliminary data showed "patients shed more virus in the early stages of the disease, including when presymptomatic." This means that previous advice to avoid contact with others if you have symptoms such as a cough or fever is not only insufficient but counterproductive, as it gives a false sense of security to those who have no symptoms.

The overall case fatality rate (CFR) - the ratio of deaths to number of people diagnosed - may be anywhere in the range 0.5-5%, with major differences between locations, and changes in CFR over time, so there is no one single figure that applies. The percentage of infected people with mild symptoms who are not diagnosed can vary between countries and has a direct influence on the CFR. About 12-30% of people who get the virus will be in serious or critical condition requiring hospitalisation: ca. 8-10% will need ICU mechanical ventilation while the rest may need concentrated oxygen treatment for possibly several weeks. The duration from the beginning of the disease until recovery is 3-6 weeks. Those who don't need to be hospitalised will take 2 weeks to recover on average. The availability of appropriate medical care for serious and critical cases obviously has a major influence on the CFR.

The long-term effects for those who survive and recover are not clear. Permanent respiratory and mental complications might occur, as has been documented in SARS and MERS. We currently have little data on lingering effects of COVID-19, but some studies point towards potential lasting damage to the lungs, liver, nervous system, kidneys and testes, and brain. There is new evidence that recovered COVID-19 patients may have reduced lung function. There is also some evidence that the outbreak may lead to cases of schizophrenia.

There might be a possibility of becoming reinfected with the virus after recovery, with possibly worse consequences the second time, but this is unclear. What may be happening is that the virus reemerges after concealing itself in the neurons from immune recognition, and so complete clearance of the virus may not be guaranteed even if the patients have recovered. (ref) There are also reports of multiple strains infecting people concurrently.

There is no vaccine, and there may not be one for some time. Although some promising candidates are being tested, it is uncertain if they will be safe enough to be released. There is also no cross-immunity with the flu.



COVID-19 usually starts with a fever (~88% of cases) and a dry cough (~68% of cases). Patients also often have fatigue (~38% of cases), but not usually a runny nose (though this doesn't rule it out). Symptoms start on average 5-6 days after infection (range 1-14 days). (ref)

Most people will have a mild form of the disease and get better without needing any special care. (ref)

In serious cases (ca. 12-30% of cases), the disease progresses to pneumonia within about a week, with symptoms including shortness of breath, rapid, shallow breathing, and a sharp or stabbing chest pain that gets worse with deep breathing or coughing. (ref)


How to protect yourself and others from being infected

Reducing physical contact

As of late March 2020, many countries are in lockdown, and measures that might have seemed extreme just a few weeks ago are now regarded as crucial. But as a general rule, protecting yourself means avoiding contact with people who are infected, and avoiding infecting yourself after touching contaminated surfaces. The degree of risk is dependent on the number of people infected in your region, and the number of people you have contact with. As infection rates have been climbing, it has become more urgent to take precautions, including avoiding travelling long distances if not essential, and avoiding large crowds. It is safest to avoid physical contact with most other people, even if they do not appear sick, and not to shake hands or kiss. At any gatherings, ensure that everyone washes their hands or uses hand disinfectant at the entrance, and people should keep a distance from one another.

The safest way to avoid infection is to isolate yourself in one place, if feasible. If you are older or with a condition that makes you more vulnerable, and especially if there are cases near you, taking this precaution may be necessary to avoid putting your life at risk. This means stocking up with at least several weeks’ worth of extra food and supplies so that you can comfortably stay at home for an extended period if you need to, until the danger has lessened (e.g. drugs become available or effective measures taken make infections much less prevalent). Supplies should include non-perishable food, medicine (anything you regularly take, paracetamol, other flu remedies), vitamins (especially vitamin D for long periods indoors), soap, toilet paper, alcohol to disinfect, hand cream. Also include items that will make your stay indoors more pleasant, including your favourite food items.

If you live in an apartment building, an additional precaution you could consider taking to prevent airflow that may be contaminated – a factor in the  spread of SARS in 2013 – is to seal vents and drains. More information in this slideshow.

The more we keep our distance, and the earlier we choose to do this, the more lives can be saved and the less suffering will be endured by the sick.


Washing hands and disinfecting surfaces

Very important, especially if you are not isolating yourself: wash your hands often, and do it carefully for at least 20 seconds. Hand sanitizer can help if you can’t find water and soap nearby, but it's not as effective. Disposable gloves are even better, but they need to be changed frequently.

Very important: avoid touching your face, especially your mouth, nose and eyes, without washing your hands first. Facial orifices are how the virus gets into the body - not through unbroken skin on your hands. Wearing gloves is useless if you touch your face with them. It’s not easy: a 2015 study found that participants touched their faces 23 times an hour. Some tips from NYT and HuffPost articles: 1. Use tissues, 2. Identify triggers and habits (nervousness, dry eyes) so you can stop them mentally or physically (e.g. keep eyes lubricated, wear glasses instead of contact lenses), 3. Keep your hands busy, touch something else (e.g. a stress ball), 4. Put up reminders, 5. Chill, practice meditation, mindfulness, intentional breathing.

Mobile phones are like a third hand that we hardly ever wash. Keep your phone disinfected by cleaning several times a day! There are a few options:

  1. Wash it with soap and water if it is waterproof (IP67 or IP68).
  2. Use wet-wipes, screen cleaning wipes (so long as they are wet with alcohol and haven't dried out), or apply isopropyl alcohol or regular alcohol (ethanol) at a concentration of at least 70%.
  3. Use a UV lamp to sterilize it.
  4. Keep your phone in a ziplock bag if you need to use it in a contaminated environment (safely dispose of the bag afterwards).

Clean surfaces with a solution of either 70% isopropyl alcohol/ethanol or 0.5% hydrogen peroxide or 0.1% sodium hypochlorite bleach. For example: work surfaces, door handles, light switches, water faucets.


Face masks

There is now a clearer understanding of the effectiveness of surgical face masks and even simple face masks made of cloth in reducing transmission through droplets produced by coughing, sneezing and even talking, thereby protecting both the wearer and others. They are most effective in preventing an infected person transmitting to others, but they also reduce exposure to the wearer, and  they can also help keep you from touching your face with your hands.  Cloth masks can be disinfected and reused. This video  by data scientist Jeremy Howard, explaining the usefulness of simple face masks, is highly recommended. See also these related links:

Some key points worth noting:

  • Blocking transmission doesn't need to be perfect to steadily reduce the number of new cases and eventually cause the pandemic to fizzle out.
  • Infection isn't all or nothing: dose matters, and the body is better able to mount an immune response in time when exposed to less virus.
  • Large institutions like the WHO and others can be slow in updating their recommendations, including on the use of face masks, in response to new data.
  • Mask-wearing after lockdowns are relaxed may be the difference between "normal" life and repeated isolation/economic disruption.

See this piece by molecular and cell biologist Sui Huang of the Institute for Systems Biology, that makes a strong argument for the use of homemade masks, as well as this Twitter thread from Yale economics professor Jason Abaluck.

More sophisticated and effective respirators masks such as  N95 (FFP2) and N100 (FFP3) create a seal around the mouth and nose. However, they are uncomfortable to wear for long periods. More importantly, highest priority must be given to healthcare workers, and as there are ongoing supply shortages, it is strongly recommended not to purchase them for personal use. More lives can be saved by far by ensuring that healthcare workers have the personal protection they need.


Maintaining a strong immune system

Getting enough sleep is important for keeping your body’s immune system in shape.

Deficiencies in some nutrients may have a negative effect on the immune system. A daily multi-vitamin or supplementation with individual nutrients can protect against this. In particular:

  • Many people have low selenium intake due to low quantities in the local soil. There is evidence that selenium deficiency can affect the immune system, and that supplementation can improve immune function. (ref) In this case, it is recommended to either take a multi-vitamin or a daily selenium supplement or 2 Brazil nuts a day.
  • There is evidence that vitamin D deficiency can affect the immune system and that supplementation can protect against respiratory tract infections. There is no evidence that high doses provide any additional protection (ref 1, ref 2), though there is evidence that there are other beneficial effects unrelated to the coronavirus. 
  • There is not yet conclusive evidence that high doses of vitamin C can help protect against viral infections, though trials are underway. It is still important to maintain adequate intake to keep the immune system healthy. (ref)
  • Zinc lozenges taken several times daily might have a prophylactic effect in addition to reducing symptoms - see section below. There is no conclusive evidence, though.


What to do if you become sick

If you suspect that you may have COVID-19, contact a healthcare professional. If you are tested positive for COVID-19 or suspect that you have it but have only mild symptoms (mild fever, cough) you should self-quarantine. If you have more serious symptoms (high fever, weakness, lethargy or shortness of breath) you should seek medical care. (ref) The most serious cases require immediate hospitalisation and mechanical ventilation.

If a person near you is experiencing respiratory distress, it is important while helping them to protect yourself and others nearby from being accidentally infected. Avoid “close contact”, which for healthcare exposures is defined as: a) being within approximately 2 metres of a person with COVID-19 for a prolonged period of time (such as caring for or visiting the patient, or sitting within 2 meters of the patient in a healthcare waiting area or room); or b) having unprotected direct contact with infectious secretions or excretions of the patient (e.g. being coughed on, touching used tissues with a bare hand). If you do not have adequate PPE (personal protective equipment), then if possible, you should remain a few meters away and call for medical help (and warn the first responders it is a potential coronavirus incident so they are adequately protected before approaching the person in need).

Treatments that may reduce symptoms and speed recovery, and that might make a critical difference if medical facilities are unable to care for all patients:

  • Chloroquine: There is good in vitro evidence (ref) and some evidence from new clinical trials that chloroquine and its close derivative hydroxychloroquine may be helpful in treating the infection. (ref) Chinese clinical trials (data not yet available as of 13 March) reported that patients treated showed better indicators on "abatement of fever, improvement of CT images of lungs, the percentage of patients who became negative in viral nucleic acid tests and the time they need to do so." (ref 1, ref 2ref 3) A report from a French clinical trial that has received a lot of attention (but which has also been criticised for its methodology) stated, "Despite its small sample size our survey shows that hydroxychloroquine treatment is significantly associated with viral load reduction/disappearance in COVID-19 patients and its effect is reinforced by azithromycin." (ref) Clinical trials are currently underway to better determine the effectiveness of these drugs. A study from China reported on 31 March that hydroxychloroquine helped to speed the recovery of a small number of patients who were mildly ill from the coronavirus, and the illness only turned severe in patients in the control group. (ref)

The two forms of chloroquine being used in trials are chloroquine phosphate (most common brand name Aralen) and hydroxychloroquine sulfate (most common brand name Plaquenil). The Chinese expert recommendation is a dosage of 2 x 500mg of chloroquine phosphate per day for 10 days. In the French trial mentioned above, all patients were proposed oral hydroxychloroquine sulfate 3 x 200 mg per day for 10 days. In South Korea, there are unconfirmed reports that they are significantly reducing the lethality of the coronavirus by prescribing 500 mg per day of chloroquine + zinc for 10 days (ref 1, ref 2).

These drugs are considered relatively safe. However, they can have toxic effects at levels not much higher than the therapeutic range, and there are rare cases of death when accidentally ingested by children or taken in large amounts by adults. Although they are not specifically approved for treatment of the coronavirus, doctors have been prescribing them off-label, and the FDA issued an emergency-use authorization. It is advisable that these drugs be taken under medical supervision, especially to rule out contraindications such as heart conditions, unless an emergency situation makes medical care unavailable. They are known to have potential serious side effects when used long term, but in the Chinese trials, short-term usage for treatment of coronavirus had no serious adverse effects in over 100 patients. Hydroxychloroquine has been found to be less toxic than chloroquine.

  • Antiviral drugs: Tamiflu (oseltamivir phosphate) and some other medications (e.g. remdesivir (ref) and Kaletra, a combination of the HIV drugs lopinavir and ritonavir) might also be helpful if available.
  • Zinc lozenges: Zinc inhibits the replication of many viruses, including coronaviruses, and seems to have an effect on some viral symptoms, including reducing the duration of cold symptoms at daily doses >75 mg. It is possible that taking a zinc lozenge (20 mg) several times a day might be helpful. (ref 1, ref 2, ref 3)
  • Ivermectin: A new study shows that ivermectin, a safe, cheap medicine used since decades to treat parasitic infections, could stop the SARS-CoV-2 virus growing in cell culture. Clinical studies will be needed to demonstrate effectiveness in humans, but there are reasons for optimism.


Resources and current data

Protection and care



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