COVID-19
Key facts about Coronavirus Disease 2019
BRIEF HISTORY OF THE PANDEMIC
On 31 December 2019, the World Health Organization (WHO) became aware of a cluster of pneumonia of unknown etiology reported in Wuhan, People’s Republic of China. On 30 January, WHO declared a Public Health Emergency of International Concern.
The virus was initially named “2019 novel coronavirus” (2019-nCoV). However, on 11 February 2020, the new coronavirus was given the official name “severe acute respiratory syndrome coronavirus 2” (SARS-CoV-2), and the disease caused by the virus was named “coronavirus disease 2019” (COVID-19). SARS-CoV-2 spread rapidly around the world and on 11 March 2020, it was characterized as a pandemic by WHO.
VIRAL TRANSMISSION
COVID-19 is believed to transmit mainly through close contact between people who are physically near each other. The SARS-CoV-2 virus appears to spread even more efficiently than the influenza virus. People that are infected but do not show symptoms (asymptomatic) can also transmit the virus to others.
Symptoms and complications
People diagnosed with COVID-19 have reported a wide range of symptoms – from none to mild symptoms to severe illness and death. To date, mortality rates have differed by country. Symptoms may appear 2-14 days after exposure to the virus and most commonly include:
- Fever
- Cough
- Headache
- Fatigue
- Muscle aches
- Loss of taste or smell
- Sore throat
- Nausea
- Diarrhea
*If an individual experiences trouble breathing, chest pain, or difficulty in staying awake – they should seek immediate medical care.
Protection and Prevention
Stay safe by taking some simple precautions such as avoiding crowds, physical distancing more than 6 feet apart, wearing a mask, cleaning your hands, keeping rooms well ventilated, coughing into your bent elbow – and getting vaccinated when available.
Download the latest COVID-19 guides and advice from the World Health Organization.
VARIANTS OF INTEREST AND CONCERN
Viruses constantly change through mutation. A variant has undergone one or more mutations that differentiate it from other variants in circulation. Multiple variants of SARS-CoV-2 have been documented globally throughout this pandemic. The variants of interest and concern are those that may cause, or are known to cause greater spread and/or more severe symptoms. The COVID-19 vaccines that are currently in development or have been approved are expected to provide at least some protection against new virus variants because these vaccines elicit a broad immune response involving a range of antibodies and cells. Therefore, changes or mutations in the virus should not render the vaccines completely ineffective. Furthermore, it will be possible to change or update the composition of the vaccines to protect against variants.
TESTING - THE CENTRAL ROLE IN THE RESPONSE
“Testing is part of the first line of defense against COVID-19, enabling early identification and isolation of cases to slow transmission, provision of targeted care to those affected, and protection of health system operations.” – World Health Organization
Viral tests
Viral tests are the recommended protocol to diagnose current COVID-19 infection. Authorized assays for viral testing include those that detect the presence of SARS-CoV-2 nucleic acid (nucleic acid tests), or SARS-CoV-2 antigens (antigen tests). These tests check for the presence of the SARS-CoV-2 virus in the respiratory system – usually by testing samples collected via nasal swab.
Nucleic acid RT-PCR laboratory tests for COVID-19 based on nucleic acid amplification techniques (NAAT) were developed in the early stage of the pandemic. This remains the gold standard for testing with regard to sensitivity – but RT-PCR tests typically require sophisticated laboratory infrastructure and skilled staff. The limited coverage of laboratory services and long turnaround times has meant that RT-PCR capacity has been insufficient to meet demand in many countries, particularly in low- and middle-income countries where these limitations have resulted in testing rates that are around 10 times lower than in high-income countries.
According to the World Health Organization (WHO)*, controlling COVID-19 requires testing services to be scaled up and access to testing to be improved in decentralized settings. They further note that timely COVID-19 testing and detailed surveillance data are vital to the COVID-19 public health response. In this regard, WHO expects that rapid diagnostic antigen tests will greatly expand access to testing – enabling the most accurate estimates of disease burden, and targeting of control measures and treatments.
“It is essential to have real-time, accurate data on the testing of suspected cases, the nature and isolation status of all confirmed cases, the number of contacts per case and completeness of tracing, and the dynamic capacity of health systems to deal with COVID-19 cases” – World Health Organization
*SARS-CoV-2 antigen-detecting rapid diagnostic tests: an implementation guide. Geneva: World Health Organization; 2020. License: CC BY-NC-SA 3.0 IGO.
Antigen testing was seen as the resultant breakthrough innovation to test for the presence of SARS-CoV-2 antigens at the point-of-care without the need for any additional equipment while returning results in 15 minutes at a significantly lower cost than the Nucleic acid RT-PCR laboratory tests. More recently, these tests are now being approved for self-testing in a home-use setting. Rapid diagnostic antigen tests can therefore be used to quickly identify those who are likely to be contagious without the need for them to leave their homes – thereby fulfilling the WHO guidelines for timely testing in managing the spread of COVID-19.
WHO recommends that persons meeting the suspected COVID-19 case definition be tested immediately in order to confirm or rule out infection with SARS-CoV-2. The most recent guidelines form the United States Centers for Disease Control and Prevention (CDC) recommend that the following groups of people should get tested for current COVID-19 infection:
- Everyone with any signs or symptoms of COVID-19, regardless of vaccination status or prior infection.
- Anyone who has had close contact (within 6 feet for a total of 15 minutes or more over a 24-hour period) with someone with confirmed COVID-19 – except those that are fully vaccinated with no COVID-19 symptoms; and those that tested positive for COVID-19 within the past 3 months and recovered and have not developed new symptoms.
- Anyone that has participated in activities that put them at higher risk for COVID-19 because they cannot physically distance as needed to avoid exposure – such as travel, attending large social or mass gatherings, or being in crowded or poorly-ventilated indoor settings.
- Anyone who has been asked or referred to get tested by their healthcare provider or health authority.
It is important to note that viral tests only determine if a person is currently infected. They cannot determine if a person was previously infected.
Antibody tests
COVID-19 antibody tests, also known as serology tests, detect the presence of antibodies to the SARS-CoV-2 virus that typically start developing after 7 days in response to an infection or vaccination. Antibody tests can be valuable in understanding the transmission dynamic of the virus in the general population – especially in previously asymptomatic cases, identifying groups at higher risk for infection, and determining the effectiveness of vaccines. Antibody tests are most effective in detecting antibodies around 15−21 days post infection or vaccination and should therefore not be used to diagnose a current COVID-19 infection.
It is important to note that the presence of antibodies resulting from either prior infection or vaccination does not guarantee immunity to the virus – there are known cases of both COVID-19 reinfection and infection despite being vaccinated. In this regard, the clinical significance of a positive antibody test is still under investigation with regard to protective immunity.
