COVID-19 is a viral infection caused by the SARS-CoV-2 coronavirus, a virus that normally affects animals but can also be transmitted to humans. It was first detected in the city of Wuhan (China) in December 2019.
Transmission between people occurs mainly through respiratory droplets expelled when talking, coughing or sneezing; also through direct contact with infected secretions from the nose, mouth or eyes, or by touching contaminated surfaces and then touching the face.
Symptoms and progression
The disease can present with a sore throat, cough, fatigue, fever and loss of smell or taste. In severe cases, it can cause breathing difficulties and pneumonia, especially in older people or those with heart disease, lung disease, diabetes or immune system disorders. Some people may experience persistent symptoms for weeks or months after infection (long COVID).
Omicron variant (B.1.1.529)
First detected in November 2021, the Omicron variant is characterised by a higher transmission capacity than previous variants, although it tends to cause milder symptoms. These mainly include a dry cough, sore throat, fatigue and fever. Loss of smell or taste is less common, but some cases are accompanied by night sweats. Severe cases continue to be more common in unvaccinated individuals or those with chronic conditions.
Diagnosis
Diagnosis is clinical and based on antigen testing. Confirmation is performed using molecular techniques (RT-PCR) and, where necessary, genetic sequencing of the virus to identify variants such as Omicron.
Treatment
Treatment is mainly based on symptom control and home isolation. Medical attention should be sought if shortness of breath, chest tightness, confusion or signs of severe infection appear.
Prevention and vaccines
Safe and effective vaccines have been developed that reduce the risk of infection and, in the event of infection, make the symptoms less severe. Vaccines may be based on attenuated viruses, viral proteins, or genetic sequences of SARS-CoV-2.
People who have been fully vaccinated can still contract post-vaccination infections and transmit the virus, but the risk of severe illness and hospitalisation is much lower. Recent studies show that those who are not vaccinated and have already had COVID-19 are more likely to be reinfected than those who have completed all recommended doses.
Links of interest:
World Health Organisation: WHO
Centres for Disease Control and Prevention: CDC
Ministry of Health, Consumer Affairs and Social Welfare: MSCBS
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