What is COVID-19 ?
- Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2).
- Common symptoms include fever, cough, fatigue, shortness of breath or breathing difficulties, and loss of smell and taste. While most people have mild symptoms, some people develop acute respiratory distress syndrome (ARDS) possibly precipitated by cytokine storm, multi-organ failure, septic shock, and blood clots. The incubation period may range from one to fourteen days.
- The disease spreads most often when people are physically close. It spreads very easily and sustainably through the air, primarily via small droplets and sometimes in aerosols, as an infected person breathes, coughs, sneezes, talks, or sings.It may also be transmitted via contaminated surfaces, although this has not been conclusively demonstrated. It can spread from an infected person for up to two days prior to symptom onset and from people who are asymptomatic.People remain infectious for seven to twelve days in moderate cases and up to two weeks in severe cases.
Sign and Symptoms
- Symptoms of COVID-19 are variable, but usually include fever and a cough. People with the same infection may have different symptoms, and their symptoms may change over time. For example, one person may have a high fever, a cough, and fatigue, and another person may have a low fever at the start of the disease and develop difficulty breathing a week later. All of the symptoms of COVID-19 are non-specific, which means that they are also seen in some other diseases.
- Symptoms of COVID-19 can be relatively non-specific; the two most common symptoms are fever (88 %) and dry cough (68 %). Among those who develop symptoms, approximately one in five may become more seriously ill and have difficulty breathing. Emergency symptoms include difficulty breathing, persistent chest pain or pressure, sudden confusion, difficulty waking, and bluish face or lips; immediate medical attention is advised if these symptoms are present.Further development of the disease can lead to complications including pneumonia, acute respiratory distress syndrome, sepsis, septic shock, and kidney failure.
- As is common with infections, there is a delay, known as the incubation period, between the moment a person first becomes infected and the appearance of the first symptoms. The median incubation period for COVID-19 is four to five days. Most symptomatic people experience symptoms within two to seven days after exposure, and almost all symptomatic people will experience one or more symptoms before day twelve.
- COVID-19 is thought to spread mainly through respiratory droplets produced when an infected person coughs, sneezes, sings, talks or breathes. A new infection occurs when those droplets get into the mouth, nose or eyes of other people who are in close contact with the infected person.The respiratory droplets evaporate into aerosols, which remain suspended in the air for longer periods of time, causing airborne transmission particularly in crowded and inadequately ventilated indoor spaces, such as restaurants, nightclubs or choirs.It also can occur in the healthcare setting, with certain aerosol-generating medical procedures performed on COVID-19 patients.
- It may be possible that a person can get COVID-19 through indirect contact by touching a contaminated surface or object, and then touching their own mouth, nose, or possibly their eyes, though this is not thought to be the main way the virus spreads. and other forms of direct contact can easily transmit the virus and thus lead to COVID-19 in people exposed to such contact. There currently is no significant evidence of COVID-19 virus transmission through feces, urine, breast milk, food, wastewater, drinking water, animal disease vectors, or from mother to baby during pregnancy, although research is ongoing and caution is advised.
- Social distancing and the wearing of cloth face masks, surgical masks, respirators, or other face coverings are controls for droplet transmission. Transmission may be decreased indoors with well maintained heating and ventilation systems to maintain good air circulation and increase the use of outdoor air.
- Face masks
The World Health Organization (WHO) and most government health agencies (such as the US Centers for Disease Control and Prevention (CDC), the UK National Health Service (NHS), or the New Zealand Ministry of Health) recommend individuals wear non-medical face coverings in public settings where there is an increased risk of transmission and where social distancing measures are difficult to maintain.This recommendation is meant to reduce the spread of the disease by asymptomatic and pre-symptomatic individuals and is complementary to established preventive measures such as social distancing. Face coverings limit the volume and travel distance of expiratory droplets dispersed when talking, breathing, and coughing.Many countries and local jurisdictions encourage or mandate the use of face masks or cloth face coverings by members of the public to limit the spread of the virus.
Masks are also strongly recommended for those who may have been infected and those taking care of someone who may have the disease.
- Social distancing
Social distancing strategies aim to reduce contact of infected persons with large groups by closing schools and workplaces, restricting travel, and cancelling large public gatherings. Distancing guidelines also include that people stay at least 2 metres (6.6 ft) apart. After the implementation of social distancing and stay-at-home orders, many regions have been able to sustain an effective transmission rate (“Rt“) of less than one, meaning the disease is in remission in those areas.
- Hand-washing and hygiene
When not wearing a mask, the CDC, WHO, and NHS recommends covering the mouth and nose with a tissue when coughing or sneezing and recommends using the inside of the elbow if no tissue is available. Proper hand hygiene after any cough or sneeze is encouraged.The WHO also recommends that individuals wash hands often with soap and water for at least 20 seconds, especially after going to the toilet or when hands are visibly dirty, before eating and after blowing one’s nose. The CDC recommends using an alcohol-based hand sanitiser with at least 60% alcohol, but only when soap and water are not readily available.For areas where commercial hand sanitisers are not readily available, the WHO provides two formulations for local production. In these formulations, the antimicrobial activity arises from ethanol or isopropanol. Hydrogen peroxide is used to help eliminate bacterial spores in the alcohol; it is “not an active substance for hand antisepsis”. Glycerol is added as a humectant.
Sanitizing of frequently touched surfaces is also recommended or required by regulation for businesses and public facilities; the United States Environmental Protection Agency maintains a list of products expected to be effective.