COVID-19
General information about the new coronavirus epidemic
The virus which originated from Wuhan, China, in late 2019 is responsible for the pneumonia epidemic SARS-CoV2. The common name of the outbreak caused by the virus is COVID-19 (Corona Virus Disease 2019).
Coronaviruses can spread from animals to humans: the scientific term for this type of infectivity is zoonosis. Thus, coronaviruses can infect humans and many animal species, typically birds and certain mammals (e.g. cats, bats), as well. At the current stage of the epidemic, human-to-human transmission has become the dominant form. Currently, 7 types of coronaviruses are known to cause symptoms in humans. Four of these types cause mild symptoms, but MERS-CoV, SARS-CoV1 and SARS-Cov2 can result in a serious illness. The virus originating from Wuhan was a hitherto unknown coronavirus strain that showed genetically similar traits to SARS-CoV. Therefore, its final name was given on 12 February 2020 with the inclusion of the marking “2”. So far, there is no evidence that the disease has undergone mutations that could affect its characteristics.
Human-to-human transmission typically occurs through direct or indirect contact via aerogenic droplets and infected secretions. People who have the virus can also infect others during the incubation period (1-14 days). In case of illness, its infectivity (i.e. viral shedding) was estimated to average 8 days in mild cases and 3 weeks in cases requiring hospitalization.
According to the World Health Organization (WHO), the disease typically begins with the following symptoms:
- fever (90%)
- coughing (70%)
- fatigue (60%)
- loss of appetite (60%)
- shortness of breath (35%)
- and muscle pain (20%).
These may be accompanied by non-specific symptoms such as:
- sore throat
- nasal obstruction
- headache
- diarrhea, nausea or vomiting
- and based on the latest data, typically loss of taste and smell prior to the onset of respiratory symptoms.
The disease most commonly materializes in mild (40%) or moderate (40%) forms, where the clinical picture can range from mild respiratory infection to non-severe pneumonia. COVID-19 is serious in 15% of the cases and in about 5% of the patients, the critical condition leads to death.
Elderly people and those with chronic illnesses may have mild initial symptoms but the risk of developing a serious disease is higher in their case. If patients treated at home experience any worsening of their symptoms (e.g. dizziness, shortness of breath, chest pain, dehydration, etc.), they should contact their GP or call the central emergency line (112) immediately.
Mortality from the age of 60 rises sharply, but smoking and chronic conditions such as cardiovascular disease, diabetes, chronic lung disease, malignant illnesses and cerebrovascular disease are also among the risk factors. Information on the manifestation of the disease in pregnant women and newborns is limited. Most of the time, the disease typically occurs in a mild or asymptomatic form, but severe and fatal outcomes have been reported in some cases as well. Pregnant women’s symptoms are similar to the clinical symptoms of non-pregnant women of the same age. To the best of our knowledge, pregnancy and childbirth alone do not exacerbate the severity and outcome of the mother’s COVID-19-related pneumonia. The available information on intrauterine fetal infection is conflicting. There is no clear evidence of fetal infection occurring in the uterus, although the possibility cannot be ruled out.
Markers of protection after overcoming the COVID-19 disease have not yet been identified. The presence of SARS-CoV-2 antibodies in a cured patient does not imply immunity, i.e. there is no evidence that an individual that successfully recovered from COVID-19 will not be able to catch the disease again. It is currently too early to determine how long the protective immune response against SARS-CoV-2 will last, as this will require long-term serological testing to monitor patients’ immunity over a longer period of time.