The signs and symptoms present at illness onset of COVID-19 vary, but over the course of the disease, most patients with confirmed COVID-19 have developed an influenza-like illness with fever and lower respiratory tract symptoms. Atypical presentations often occur and older adults and person with medical co-morbidities may have delayed presentation of fever and respiratory symptoms. Asymptomatic infections have been well documented as well.
Symptoms commonly reported among adults with COVID-19 include:
Various other symptoms have been associated with COVID-19, see CDC Interim Clinical Guidance for Management of Patients with Confirmed Coronavirus Disease for a more detailed discussion of COVID-19 presentations in adults. Signs and symptoms of COVID-19 in children vary by age of the child, and are usually milder compared to adults. For more information on the clinical presentation and course among children, see Information for Pediatric Healthcare Providers.NOTE: Clinical presentation among reported cases of COVID-19 varies in severity from asymptomatic infection to mild illness to severe or fatal illness. Some reports suggest the potential for clinical deterioration during the second week of illness.
In the absence of a more likely diagnosis:
Nasal and pharyngeal secretions.
There are three principal ways in which infectious exposures to respiratory fluids carrying SARS-CoV-2 occur:
Inhalation plays a larger role than previously believed, as aerosolized particles can remain in the air for minutes to hours. This is more likely in enclosed spaces with poor ventilation, especially if an infectious person spends an extended period in that space or if they are participating in activities that increase exhalation of respiratory fluids, such as vigorous exercise, singing, or shouting.
Read CDC's Scientific Brief: SARS-CoV-2 Transmission.
For CDC patient-friendly information, see How COVID-19 Spreads.
Asymptomatic persons with laboratory confirmed COVID-19 are considered infectious from 2 days before the date of their first positive molecular test (e.g. PCR) until at least 10 days* after the initial positive PCR test, barring the development of symptoms.
*For patients with severe to critical illness, the CDC recommends extending the duration of isolation or precautions from 10 days to up to 20 days from illness onset.
Severely immunocompromised patients (e.g., currently receiving chemotherapy for cancer, uncontrolled HIV infection with current CD4 <200, prednisone treatment >20mg/kg for more than 14 days) may produce replication-competent virus beyond 20 days and require additional testing and consultation with infectious diseases specialists and infection control experts.
Note: for certain populations where there is an especially low tolerance for post-recovery viral shedding and/or increased risk of infection such as skilled nursing facilities the transmission-based precautions/patient isolation is continued for 15-20 days post initial symptoms/date of test collection).
A close contact is a person with exposure to a confirmed or suspected case of COVID-19 during the period of infectiousness of the case (see Communicability/Period of Infectiousness above). This is from 2 days before symptom onset (or date of first positive lab test for asymptomatic persons) until the case meets criteria for discontinuing isolation/transmission-based precautions.
Exposures are generally defined as:
A person is still considered exposed even if the case or the contact was wearing a face covering.
Exception: Cal-OSHA’s Emergency Temporary Standards (ETS) state that employees have not had a close contact if they were wearing a respirator required by the employer and used in compliance with section 5144 of the ETS when they were within six feet of a case during the high-risk exposure period.
See site specific B73 for more specific guidance on determining close contacts. For more information see CDC Public Health Guidance for Community-Related Exposure.
Supportive care (e.g., rest, antipyretics, fluids, etc.). Patients with a mild clinical presentation may not initially require hospitalization. However, clinical signs and symptoms may worsen with progression to lower respiratory tract disease; all patients should be monitored closely.
The National Institutes of Health have published interim guidelines for the medical management of COVID-19 prepared by the COVID-19 Treatment Guidelines Panel. Providers should make treatment decisions based on currently available evidence.
Natural immunity: The duration and robustness of immunity to SARS-CoV-2 remains under investigation. Among other human coronaviruses, reinfection appears to occur variably over time after onset of infection. SARS-CoV-2 reinfection appears to be uncommon during the initial 90 days after symptom onset of the preceding infection. The likelihood of re-infection is expected to increase over time because of waning immunity and the possibility of exposure to virus variants. See CDC Interim Guidance on Ending Isolation and Precautions for Adults with COVID-19.
Vaccine-induced immunity: Currently authorized vaccines in the United States are highly effective at protecting vaccinated people against symptomatic and severe COVID-19. Fully vaccinated people are less likely to become infected and, if infected, to develop symptoms of COVID-19. Per the CDC, there is preliminary evidence that suggests that fully vaccinated people who do become infected with the Delta variant can be infectious and can spread the virus to others.
Clinical and epidemiologic histories are required to aid in diagnosis. Direct viral detection methods with sensitive molecular tests (e.g. RT-PCR) are recommended for diagnosing current infection with SARS-CoV-2. Antigen tests can also be used to diagnose acute infection but they are less accurate than PCR tests.
When using lower sensitivity assays (e.g. antigen tests and some molecular tests), negative results are considered presumptive and confirmation with RT-PCR is recommended, especially if important for clinical management or infection control.
Serological testing is not a standard part of outbreak investigation.
See LAC DPH Currently Available SARS-CoV-2 Tests for an overview of test types.
Facilities are encouraged to test through a commercial lab. Facilities should follow the specimen collection and pick-up instructions as per the facility’s designated commercial clinical laboratory. They should work directly with the clinical laboratory for all questions regarding specimen collection and transport.
See Laboratories Providing Diagnostic Testing for resources to support organizations identify a laboratory provider that best fits their needs.
PHL SARS CoV-2 PCR Specimen Collection
Upper Respiratory Specimen--for initial diagnostic testing, collect at least one upper respiratory specimen.
Any of the following specimens are acceptable:
Swabs: Acceptable swab types include synthetic fiber swabs (flocked or spun polyester) with plastic or wire shafts. Do not use calcium alginate swabs or cotton swabs with wooden shafts. Place swab in a minimum of 1-3 mL viral transport media, liquid Amies, or saline.
Aspirates and washes: collect 1.5-3.0 mL in a sterile, leak-proof container.
Lower respiratory tract specimens--may be required for patients presenting with severe disease or fatal cases. Acceptable lower respiratory tract specimens include sputum, bronchoalveolar lavage, tracheal aspirate, pleural fluid, lung swab, or lung biopsy. Collect lower respiratory tract specimens in a sterile, leak-proof container. Lung swab should be submitted in viral transport media. A minimum of 2-3 mL is needed for sputum, lavage and aspirates.
Storage: Refrigerate specimens at 2-8°C and transport on cold pack. If specimen storage exceeds 3 days, freeze specimen at ≤ -70°C and ship on dry ice.
For more information see:
A person is considered fully vaccinated ≥2 weeks following the receipt of:
* This guidance can also be applied to COVID-19 vaccines that have been listed for emergency use by the World Health Organization (e.g., AstraZeneca/Oxford). See CDC Clinical Considerations People vaccinated outside the Unites States footnote 2 for current WHO list.
Fully vaccinated persons who are a close contact to a confirmed COVID-19 case:
Individuals who have recovered from laboratory-confirmed* COVID-19, for 90 days after the onset of the initial COVID-19 illness (or date of first positive viral test if they never had symptoms):