Questions and answers on COVID-19: Basic facts
- What is SARS-CoV-2? What is COVID-19?
Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is the name given to the 2019 novel coronavirus. COVID-19 is the name given to the disease associated with the virus. SARS-CoV-2 is a new strain of coronavirus that has not been previously identified in humans.
- Where do coronaviruses come from?
Coronaviruses are viruses that circulate among animals, with some infecting humans.
Bats are considered natural hosts of these viruses, and several other species of animals are also known to act as sources. For instance, Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is transmitted to humans from camels, while Severe Acute Respiratory Syndrome Coronavirus-1 (SARS-CoV-1) is transmitted to humans from civet cats.
Latest evidence on COVID-19
- Is this virus comparable with SARS or with the seasonal flu?
The novel coronavirus detected in China in 2019 is closely related genetically to the SARS-CoV-1 virus. SARS emerged in late 2002 in China, and caused more than 8 000 cases in 33 countries over the course of eight months. Around one in 10 of people who developed SARS died.
In the first eight months of the COVID-19 pandemic (from 31 December 2019 to 31 August 2020), there were over 25 million cases worldwide and more than 840 000 deaths.
While the viruses that cause both COVID-19 and seasonal influenza are transmitted from person to person and may cause similar symptoms, the two viruses are different.
ECDC estimates that between 15 000 and 75 000 people die prematurely every year in the European Union (EU), the United Kingdom (UK), Norway, Iceland and Liechtenstein due to causes associated with seasonal influenza infection. This represents approximately one in every 1 000 people who are infected. Despite the relatively low mortality rate for seasonal influenza, many people die from the disease due to the large number of people who contract it each year. Unlike influenza, there is not yet a vaccine for COVID-19, and only limited treatment options are currently available for the disease. It also appears to be more transmissible than seasonal influenza, although it has a milder clinical course in young children. As it is a new virus, nobody has prior immunity to it, which means that the entire human population is potentially susceptible to SARS-CoV-2 infection.
- How does the virus spread?
SARS-CoV2 spreads from person to person (human-to-human transmission) through direct contact. It is currently estimated that, in the absence of physical distancing and other preventive measures, one infected person will on average infect between two and three other people.
The virus is transmitted mainly via respiratory droplets and aerosols when sneezing, coughing, or interacting with others in close proximity (usually less than two metres. These droplets can be inhaled or can land on surfaces that others come into contact with and are then infected when they touch their nose, mouth or eyes. The virus can survive on surfaces from between several hours (copper, cardboard) up to a few days (plastic and stainless steel). However, the amount of viable virus declines over time and may not always be present in a sufficient amount to cause infection.
The incubation period for COVID-19 (i.e. the time between exposure to the virus and the onset of symptoms) is currently estimated to be between one and 14 days.
We know that the virus can be transmitted when people who are infected show symptoms such as coughing. A person who is infected can also transmit the virus up to two days before they show symptoms; the extent to which such asymptomatic infections contribute to the overall transmission is not currently clear.
- When is a person infectious?
The infectious period may begin up to two days before symptoms appear, but people are most infectious during the symptomatic period, even if symptoms are mild and non-specific. The infectious period is estimated to last for eight to 10 days in moderate cases, and up to two weeks on average in severe cases.
- How severe is COVID-19 infection?
Data from the EU/European Economic Area (from the countries with available data) show that around 20–30% of diagnosed COVID-19 cases are hospitalised, and 2% of those have severe illness. It is important to note, however, that people with more severe symptoms are more likely to be tested than those with less severe symptoms. The real proportion of people requiring hospital admission from the overall number of infected individuals is therefore lower than these figures suggest. Hospitalisation rates are higher for those aged 60 years and above, and for those with underlying health conditions.
Questions and answers on COVID-19: Medical information
- What are the symptoms of COVID-19 infection
Symptoms of COVID-19 vary in severity from having no symptoms at all (being asymptomatic) to having fever, cough, sore throat, general weakness, fatigue and muscular pain. The most severe cases can develop severe pneumonia, acute respiratory distress syndrome and other complications, all potentially leading to death. Reports show that clinical deterioration can occur rapidly, often during the second week of disease.
Anosmia – loss of the sense of smell – (and in some cases the loss of the sense of taste) have been recognised as symptoms of a COVID-19 infection.
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- Are some people more at risk than others?
People older than 60 years and those with underlying health conditions (e.g. hypertension, diabetes, cardiovascular disease, chronic respiratory disease and immune suppression) are considered to be more at risk of developing severe symptoms. Men in these groups also appear to be at a slightly higher risk than females.
- Are children also at risk of infection and what is their potential role in transmission?
Children make up a small proportion of reported COVID-19 cases in the reported data. According to data from The European Surveillance System (TESSy), children aged under 10 years and 10-19 years represent 1 and 1.5%of cases, respectively. Children appear as likely to be infected with COVID-19 as adults with increased transmissibility in children older than 12 years of age. However, children tend to have a much lower risk than adults of developing symptoms or severe disease. Vomiting, diarrhoea and gastrointestinal symptoms in general are more common in children. There is still some uncertainty about the role children play in the spread of COVID-19. ECDC continues to monitor the science regarding the role of children in ongoing transmission.
- What is the risk of infection in pregnant women and newborn babies?
Existing data indicate that pregnant women experience similar illness and symptoms as non-pregnant women who have contracted SARS-CoV-2. Pregnant women who have diabetes and/or are obese may experience more severe disease.
The current evidence is not conclusive regarding in utero transmission of SARS-CoV-2. A limited number of cases have been reported with good overall outcomes and no severe illness for the newborn. ECDC will continue to monitor the emerging scientific literature on this question, and suggests that all pregnant women follow the same general precautions for the prevention of COVID-19, including regular handwashing, avoiding individuals who are sick and self-isolating in case of any symptoms, while consulting a healthcare provider by telephone for advice.
- Is there any treatment for COVID-19 disease?
Healthcare providers provide supportive care (e.g. oxygen therapy, management of fluids) to hospitalised patients, mostly using a symptomatic approach, meaning they treat the symptoms rather than target the virus. This which can be highly effective.
In severe and critically ill patients, several drugs are being tested to target the virus as part of randomised controlled trials. From those trials, we currently have evidence that the antiviral drug remdesivir can help patients with severe disease by shortening their recovery time and improving outcomes. Dexamethasone, a corticosteroid, is also beneficial for severe disease (i.e. patients who require oxygen). Finally, the use of plasma from persons who have recovered from COVID-19 (convalescent plasma) has also shown modest benefits.
The evidence suggests that the antimalarial drug hydroxychloroquine does not provide additional benefit to the treatment of COVID-19 patients, and some patients also exhibit side effects. Several other drugs and antibody preparations are under assessment.
- When and where should I be tested for COVID-19?
Current advice for testing depends on the stage of the outbreak in the country or area where you live. Testing approaches will be adapted to the situation at national and local level. National authorities may decide to test only subgroups of suspected cases based on the level of community transmission of COVID-19, or other criteria. Contact your local authorities to inquire about whether and where you should be tested.
- Do persons suffering from pollen allergy or allergies in general have a higher risk of developing COVID-19 more severely?
A large proportion of the population (up to 20%) reports seasonal allergic symptoms related to pollen, the most common of which include itchy eyes, nasal congestion, runny nose and sometimes wheezing and skin rashes. All these symptoms are usually referred to as hay fever, pollen allergy or allergic rhinitis. Allergic rhinitis is commonly associated with allergic asthma in children and adults.
Allergies, including mild allergic asthma, have not been identified as a major risk factor for SARS-CoV-2 infection or for a more unfavourable outcome in studies so far. Moderate to severe asthma, however, for which patients need daily treatment, is included in the chronic lung conditions that predispose to severe disease.
Children and adults on maintenance medication for allergies (e.g. leukotriene inhibitors, inhaled corticosteroids and/or bronchodilators) need to continue their treatment as prescribed by their doctor and should not discontinue their medication due to fears of COVID-19. If they develop symptoms compatible with COVID-19, they will need to self-isolate, inform their doctor and monitor their health as everyone else. If progressive difficulty in breathing develops, they should seek prompt medical assistance.
- How can we differentiate between hay fever/pollen allergy related respiratory symptoms and COVID-19 infection?
COVID-19 symptoms are usually mild and flu-like. These are rather common symptoms and need to be distinguished from similar symptoms caused by common cold viruses and from allergic symptoms during springtime. The only way to definitively determine whether someone has COVID-19 is by taking a RT-PCR test. However, the following table presents a comparison of the most common symptoms of the common cold, hay fever and COVID-19.
Table: comparison of common symptoms between common cold, hay fever and COVID-19
| Illness | Common cold | Hay fever (pollen allergy) | COVID-19 |
| Fever | ± Sometimes usually <38.5°C | No | ++ Yes, (maybe high grade) |
| Cough | + Sometimes | ± Sometimes | +++ Yes, persistent dry cough |
| Runny/stuffy nose | ++ Yes | +++ Yes | ± Sometimes |
| Sneezing | ++ Yes | +++ Yes | ± Sometimes |
| Headache | + Yes | + Yes | +++ Yes |
| Myalgia | No | No | +++ Yes |
| Anosmia (loss of smell) | ± Sometimes | ± Sometimes | ± Sometimes, suddenly and a specific symptom |
| Conjunctivitis | ± Sometimes, depends on the virus | +++ Yes | ++ Yes |
| Skin rash | No | ++ Yes | ++ Yes, involving fingers and toes |
| Fatigue | ± Sometimes | ± Sometimes | +++ Yes |
| Difficulty breathing | No | ± Sometimes, esp. if allergic asthma | ++ Yes, in moderate to severe cases accounting for about 20% of infected |
| Nausea, Vomiting, Diarrhea | No | No | ± Sometimes, particularly in children |
| Symptoms relieved by antihistamines | + Antihistamines are included in OTC cold medications to relieve runny nose | +++ Yes | No |
- Should people who suffer from pollen allergy self-isolate if they develop typical hay fever symptoms?
No. There is no more reason for people suffering from a known pollen allergy to self-isolate if they develop their typical hay fever symptoms than for anyone else. They should continue following the general guidance for physical distancing, wear a face mask as recommended, and seek medical advice if their symptoms get worse, if they develop fever or if they have progressive difficulty breathing.