COVID-19

Coronavirus disease 2019 (COVID-19) is a contagious disease caused by the SARS-CoV-2 virus that spread worldwide, resulting in the COVID-19 pandemic. Symptoms include fever, fatigue, cough, breathing difficulties, and loss of smell or taste, with varying severity ranging from mild to severe.

Transmission and Prevention

The transmission occurs through airborne particles, contact with contaminated surfaces, or touching one’s eyes, nose, or mouth after touching a surface. People remain contagious for up to 20 days. Preventive measures include physical distancing, quarantine, ventilation of indoor spaces, use of face masks or coverings, hand washing, and keeping unwashed hands away from the face.

Vaccines and Treatment

Vaccines have been approved, and treatment primarily involves symptomatic management with supportive care and isolation. The first case was identified in Wuhan, China, in December 2019, and scientists believe SARS-CoV-2 entered human populations through natural zoonosis.

Impact on the Body

The many thousands of SARS-CoV-2 variants are grouped into clades or lineages. The WHO has established nomenclature systems for naming and tracking SARS-CoV-2 genetic lineages. Notable variants include Alpha (B. 1. 1. 7), Beta, Gamma, Delta, and Epsilon, with the Alpha variant being dominant globally as of December 2021.

Following COVID-19 infection, children may develop paediatric multisystem inflammatory syndrome, Kawasaki disease-like symptoms can be fatal. Pregnant women are at increased risk of becoming seriously ill with COVID-19, leading to respiratory and obstetric complications. Fungal infections such as aspergillosis and mucormycosis have been recorded in people recovering from COVID-19.

Effects on the Body

The virus affects both central and peripheral nervous systems, causing neurological issues in many people. Research suggests COVID-19 may cause brain damage, with different variants killing varying types of brain cells. It is unknown if such damage is temporary or permanent.

Up to 30% of people hospitalized with COVID-19 have experienced some injury to their kidneys, including those with no previous kidney problems. Systemic hyperinflammation is observed in people with severe COVID-19. Clinical laboratory findings suggest an underlying immunopathology involving elevated IL-2, IL-6, and other cytokines.

Long-term Effects

The severity of inflammation is attributed to the cytokine storm, with increased levels of interleukin 1B, interferon-gamma, and monocyte chemoattractant protein 1 associated with COVID-19 disease severity. Long-term effects of COVID-19 include cognitive deficits, dementia, and other neurological disorders persisting after infection.

Children’s lung function can take up to a year or more to return to previous levels after severe disease, while pulmonary fibrosis persists in approximately one-third of those investigated. Those with asymptomatic or mild disease had undetectable levels of neutralising antibody two months after infection. However, the lack of antibodies in the blood does not mean antibodies will not be rapidly produced upon reexposure to SARS-CoV-2.

Diagnosis and Outbreaks

Chest CT scans can show characteristic imaging features, including bilateral multilobar ground-glass opacities and consolidation. The WHO has assigned emergency ICD-10 disease codes for COVID-19-related deaths and pathologically confirmed findings at autopsy include pericarditis, lung consolidation, and pulmonary oedema.

Outbreaks occurred in prisons due to crowding and inability to enforce adequate social distancing. Surface cleaning is not the main driver of COVID-19 transmission. Self-isolation at home has been recommended for those diagnosed with COVID-19 and those who suspect they have been infected. Governments have mandated or recommended self-quarantine for entire populations, especially those in high-risk groups.

Preventive Measures

The first COVID-19 vaccine was granted regulatory approval on 2 December 2020. Prevention measures include face masks and respiratory hygiene, indoor ventilation and avoiding crowded indoor spaces, hand-washing and hygiene, social distancing. Methods include quarantines; travel restrictions; and closing schools, workplaces, stadiums, theatres, or shopping centres.

Restricting cross-border travel may help contain the spread of COVID-19, according to a 2021 Cochrane rapid review. The severity of COVID-19 varies, ranging from mild cases to severe or critical diseases. Symptoms can take two weeks to recover, while hospitalized patients may take three to six weeks to recover.

Conclusion

The impact of the SARS-CoV-2 virus on human health is profound and multifaceted, affecting not only the respiratory system but also the nervous, cardiovascular, and immune systems. As we continue to navigate this pandemic, understanding its complexities and implementing effective preventive measures remain crucial for mitigating its effects.