COVID-19 SARS-CoV-2 spreads through close contact, primarily by respiratory droplets produced when an infected person coughs, sneezes, sings, exercises, or chats. Large respiratory droplets that can travel short distances and fall directly on mucosal surfaces or small respiratory particle aerosols that can linger in the air for several hours and travel greater distances (> 6 feet) before being inhaled are used to spread the disease. Contact with surfaces polluted (fomites) by respiratory secretions could possibly spread the virus if a person contacts a contaminated surface and subsequently touches a mucous membrane on the face (eyes, nose, mouth). It’s well recognized that both asymptomatic and symptomatic patients can spread the virus, making containment challenges.
A person is most contagious in the days leading up to and following the start of symptoms when the virus load in respiratory secretions is at its highest. The SARS-CoV-2 virus is rapidly transmitted from person to person. The amount of virus to which a person is exposed determines the risk of transmission. The higher the risk of virus dissemination, the closer and longer the interaction with an infected individual. Distance from an infected person, the number of infected people in the room, the amount of time spent with infected people, the size of the air space, aerosol-producing activity (such as singing, shouting, or exercising), ventilation, and the direction and speed of airflow can all contribute to this risk
Congregate living facilities (e.g., nursing homes, long-term care facilities, residential schools, prisons, and ships) as well as crowded, poorly ventilated environments (e.g., indoor religious services, gyms, bars, nightclubs, indoor restaurants, and meat-packing facilities) pose a high risk of transmission. High population density and difficulty in sustaining avoidance procedures are common in such scenarios. Nursing home residents are also at a higher risk of developing serious illnesses due to their age and underlying medical conditions.
Quarantine and Isolation
Quarantine and isolation procedures are being implemented in an attempt to contain the outbreak’s spread on a local, regional, and global scale.
Quarantine is designed to keep persons who have had “close contact” with a contagious person separated and restricted from infecting others.
Close contact is defined as being within 6 feet of a SARS-CoV-2 infected person for 15 minutes or more in a 24-hour period. If asymptomatic, an exposed person can start transmitting the illness two days before symptoms appear or before a positive test.
Close contact is defined as being within 3 feet of an infected individual for children in kindergarten through 12th grade in an indoor or outdoor classroom setting where masks were worn correctly and regularly.
Quarantine begins on the day of close contact, which is Day 0 of the quarantine period (counting days of quarantine starts on Day 1). People who have not been vaccinated against COVID-19 should stay in quarantine until Day 5 and wear a well-fitting mask until Day 10. If quarantine is not an option, the person should wear a well-fitting mask whenever they are with other people until Day 10.
- People who have had all of their COVID-19 immunizations.
- People who had COVID-19 infection within 90 days of exposure (confirmed by a positive SARS-CoV-2 virus test).
- An exposed person should get a SARS-CoV-2 virus test 5 to 7 days after exposure, even if asymptomatic and regardless of vaccination status.
If symptoms occur, the affected individual should separate until a negative test indicates that the symptoms are not caused by COVID-19.
People with confirmed or suspected COVID-19 are isolated from those who do not have COVID-19. People with COVID-19 symptoms and/or a positive SARS-CoV-2 viral test should be isolated, according to the CDC. Isolated people should either stay at home and away from others or wear a well-fitting mask when they need to be among other people in the house.
Isolation should begin on the day of the beginning of symptoms or a positive viral test, which is Day 0 (counting days of isolation begins on Day 1) and last at least until Day 5.
If people are asymptomatic or their symptoms are resolving (eg, afebrile for 24 hours without antipyretics; other symptoms improving), they can discontinue isolation on Day 6. When they’re with other people, they should wear a well-fitting mask until Day 10.
If an antigen test is available, it can be performed on or after Day 5 of the isolation period. Isolation should be continued through Day 10 if the test is positive. If the test is negative and the clinical requirements are met, isolation can be lifted, but a well-fitting mask should be worn among people at home and anywhere else until Day 10.
- People who were seriously unwell should stay in isolation for at least 10 days.
COVID-19 Symptoms and Signs
In persons with COVID-19, the degree and pattern of symptoms vary. Some people have few to no symptoms, while others become very sick and die. Among the signs and symptoms are:
- Sore throat
- Congestion or runny nose
- Shortness of breath or difficulty breathing
- Chills or repeated shaking with chills
- New loss of smell or taste
- Muscle pain
- Nausea or vomiting
The incubation period (the time from exposure to symptom start) for the Omicron variant ranges from 2 to 14 days, with a median estimate of only 2 to 4 days. Many infected people (up to 80%) experience no or minor symptoms; however, this varies according to the variation. COVID-19 cases have a higher risk of serious disease and death as they get older, if they smoke, or if they have other serious medical conditions like cancer, heart, lung, kidney, or liver disease, diabetes, immunocompromising conditions, sickle cell disease, or obesity. Vaccination reduces the risk of serious illness in people of all ages, and decreased vaccination rates in younger people have shifted the age demography of hospitalized patients (see CDC: COVID Data Tracker). Dyspnea, hypoxia, and significant lung involvement on imaging are all signs of severe illness. Respiratory failure, which necessitates mechanical ventilation, shock, multiorgan failure, and death are all possible outcomes.
Symptoms usually go away in about a week for the majority of individuals. However, after a week, some patients’ clinical condition deteriorates, leading to severe diseases, such as ARDS. Even individuals with a minor illness may experience symptoms such as dyspnea, cough, and malaise that linger for weeks or months. In patients with severe disease, longer sickness appears to be more likely. Regardless of symptoms, viral PCR tests in patients can be positive for up to three months. Even individuals with persistent symptoms are rarely if ever, deemed infectious because the virus can only be cultivated from the upper respiratory tract of patients after 10 days of sickness.
COVID-19 has also been linked to long-term consequences after an acute illness (4), with symptoms lasting months. Long COVID, long-haul COVID, and post-acute COVID-19 syndrome or condition are all terms used to describe this syndrome or condition, which is believed to affect 25 to 50 percent of all patients in various US surveys. Fatigue, weakness, discomfort, myalgias, dyspnea, and cognitive impairment are all prevalent complaints. More severe illness presentation, older age, female sex, and pre-existing lung disease are all risk factors for long-term consequences. To aid in the diagnosis and further exploration of this illness, an international case definition was recently established.
Upper and lower respiratory secretions are tested using a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) or another nucleic acid amplification test (NAAT).
Upper respiratory secretion antigen testing
COVID-19 testing should be done on the following people:
- While waiting for test results, people who have indications or symptoms of COVID-19 should separate themselves.
- People who have had close contact with a COVID-19-infected person are tested 5 days after the last interaction and are quarantined if they are not up-to-date on COVID-19 immunizations.
- People who have not had their COVID-19 vaccines are given priority for COVID-19 community screening.
- People who have been asked to take a test because of education, job, health care, or government responsibilities.
Treatment of Covid 19
COVID-19 treatment is determined by the severity of the illness and the possibility of the patient developing severe disease. This is a fast-changing field, with new research being published on a regular basis. ( see National Institutes of Health (NIH) Covid-19 Treatment Guidelines.
- Assistive care
- Sometimes, for mild to moderate illness with a high risk of severe disease: nirmatrelvir in combination with ritonavir; molnupiravir; neutralizing monoclonal antibodies; remdesivir (short course).
- Remdesivir, dexamethasone, and immunomodulators are used to treat severe sicknesses.
Patients with mild to moderate COVID-19 who are at high risk of developing severe illness should receive treatment.
These medications are for COVID-19 patients who are ambulatory or hospitalized for reasons other than COVID-19; therapeutic options (other than remdesivir) have not been investigated in COVID-19 patients who are hospitalized for COVID-19.
Because there are no data on combination therapy with currently available medications, only one drug should be used. Due to supply and administration constraints, practitioners may be forced to prioritize patients who are most likely to benefit. Patients who are contaminated rather than infected and are unvaccinated, inadequately vaccinated, or vaccinated but not estimated to generate an appropriate immune response due to immunocompromising factors fall into this category.